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Plewa J, Płońska M, Junak G. Studies of Auxetic Structures Assembled from Rotating Rectangles. Materials (Basel) 2024; 17:731. [PMID: 38592007 PMCID: PMC10856801 DOI: 10.3390/ma17030731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 04/10/2024]
Abstract
The subject of the work is analysis, which presents a renowned auxetic structure based on so-called rotating polygons, which has been subject to modification. This modification entails introducing pivot points on unit cell surfaces near rectangle corners. This innovative system reveals previously unexplored correlations between Poisson's ratio, the ratio of rectangle side lengths, pivot point placement, and structural opening. Formulas have been derived using geometric relationships to compute the structure's linear dimensions and Poisson's ratio. The obtained findings suggest that Poisson's ratio is intricately tied to the structure's opening degree, varying as the structure undergoes stretching. Notably, there are critical parameter limits beyond which Poisson's ratio turns positive, leading to the loss of auxetic properties. For elongated rectangles, extremely high negative Poisson's ratio values are obtained, but only for small opening angles, while with further stretching, the structure loses its auxetic properties. This observed trend is consistent across a broad category of structures comprised of rotating rectangles.
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Affiliation(s)
- Julian Plewa
- Faculty of Science and Technology, Institute of Materials Engineering, University of Silesia in Katowice, 75 Pułku Piechoty Str. 1a, 41-500 Chorzów, Poland;
| | - Małgorzata Płońska
- Faculty of Science and Technology, Institute of Materials Engineering, University of Silesia in Katowice, 75 Pułku Piechoty Str. 1a, 41-500 Chorzów, Poland;
| | - Grzegorz Junak
- Faculty of Materials Engineering, Silesian University of Technology, 44-100 Gliwice, Poland;
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2
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Kornfellner E, Königshofer M, Krainz L, Krause A, Unger E, Moscato F. Measured and simulated mechanical properties of additively manufactured matrix-inclusion multimaterials fabricated by material jetting. 3D Print Med 2024; 10:4. [PMID: 38305928 PMCID: PMC10835942 DOI: 10.1186/s41205-023-00201-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 12/12/2023] [Indexed: 02/03/2024] Open
Abstract
Modern additive manufacturing enables the simultaneous processing of different materials during the printing process. While multimaterial 3D printing allows greater freedom in part design, the prediction of the mix-material properties becomes challenging. One type of multimaterials are matrix-inclusion composites, where one material contains inclusions of another material. Aim of this study was to develop a method to predict the uniaxial Young's modulus and Poisson's ratio of material jetted matrix-inclusion composites by a combination of simulations and experimental data.Fifty samples from commercially available materials in their pure and matrix-inclusion mixed forms, with cubic inclusions, have been fabricated using material jetting and mechanically characterized by uniaxial tensile tests. Multiple simulation approaches have been assessed and compared to the measurement results in order to find and validate a method to predict the multimaterials' properties. Optical coherence tomography and microscopy was used to characterize the size and structure of the multimaterials, compared to the design.The materials exhibited Young's moduli in the range of 1.4 GPa to 2.5 GPa. The multimaterial mixtures were never as stiff as the weighted volume average of the primary materials (up to [Formula: see text] softer for 45% RGD8530-DM inclusions in VeroClear matrix). Experimental data could be predicted by finite element simulations by considering a non-ideal contact stiffness between matrix and inclusion ([Formula: see text] for RGD8530-DM, [Formula: see text] for RGD8430-DM), and geometries of the printed inclusions that deviated from the design (rounded edge radii of [Formula: see text]m). Not considering this would lead to a difference of the estimation result of up to [Formula: see text]MPa (44%), simulating an inclusion volume fraction of 45% RGD8530-DM.Prediction of matrix-inclusion composites fabricated by multimaterial jetting printing, is possible, however, requires a priori knowledge or additional measurements to characterize non-ideal contact stiffness between the components and effective printed geometries, precluding therefore a simple multimaterial modelling.
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Affiliation(s)
- Erik Kornfellner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
| | - Markus Königshofer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Lisa Krainz
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Arno Krause
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Ewald Unger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Francesco Moscato
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Vienna, Austria
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3
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Kojima S. Poisson's Ratio of Glasses, Ceramics, and Crystals. Materials (Basel) 2024; 17:300. [PMID: 38255468 PMCID: PMC10817342 DOI: 10.3390/ma17020300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/04/2024] [Accepted: 01/04/2024] [Indexed: 01/24/2024]
Abstract
Poisson's ratio is the fundamental metric used to discuss the performance of any material when strained elastically. However, the methods of the determination of Poisson's ratio are not yet discussed well. The first purpose of this paper is to introduce the five kinds of typical experimental methods to measure Poisson's ratio of glasses, ceramics, and crystals. The second purpose is to discuss the experimental results on the variation of Poisson's ratio by composition, temperature, and pressure reviewed for various glasses, ceramics, and crystals, which are not yet reviewed. For example, in oxide glasses, the number of bridging oxygen atoms per glass-forming cation provides a straightforward estimation of network crosslinking using Poisson's ratio. In the structural-phase transition of crystals, Poisson's ratio shows remarkable temperature-dependence in the vicinity of a phase-transition temperature. The mechanism of these variations is discussed from physical and chemical points of view. The first-principles calculation of Poisson's ratio in the newly hypothesized compounds is also described, and its pressure-induced ductile-brittle transition is discussed.
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Affiliation(s)
- Seiji Kojima
- Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
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4
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Rich MJ, Burnash S, Krishnan RR, Chubinskaya S, Loeser RF, Polacheck WJ, Diekman BO. Use of a novel magnetically actuated compression system to study the temporal dynamics of axial and lateral strain in human osteochondral plugs. J Biomech 2024; 162:111887. [PMID: 38128469 PMCID: PMC10872462 DOI: 10.1016/j.jbiomech.2023.111887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 10/23/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023]
Abstract
The high water content of articular cartilage allows this biphasic tissue to withstand large compressive loads through fluid pressurization. The system presented here, termed the "MagnaSquish", provides new capabilities for quantifying the effect of rehydration on cartilage behavior during cyclic loading. An imbalanced rate of fluid exudation during load and fluid re-entry during recovery can lead to the accumulation of strain during successive loading cycles - a phenomenon known as ratcheting. Typical experimental systems for cartilage biomechanics use continuous contact between the platen and sample, which may affect tissue rehydration by compressing the top layer of cartilage and slowing fluid re-entry. To address this limitation, we developed a magnetically actuated device that provides full lift-off of the platen in between loading cycles. We investigated strain accumulation in cadaveric human osteochondral plugs during 750 loading cycles, with two dimensional profiles of the cartilage captured at 30 frames per second throughout loading and 10 min of additional free swelling recovery. Axial and lateral strain measurements were extracted from the tissue profiles using a UNet-based deep learning algorithm to circumvent manual tracing. We observed increased axial strain accumulation with shorter inter-cycle recovery, with static loading serving as the extreme case of zero recovery. The loading waveform during the 750 cycles dictated the pace of the recovery during the extended free swelling period, as shorter inter-cycle recovery led to more persistent axial strain accumulation for up to five minutes. This work showcases the importance of fluid re-entry in resisting strain accumulation during cyclical compression.
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Affiliation(s)
- Matthew J Rich
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill (UNC), Chapel Hill, NC, United States; Joint Department of Biomedical Engineering, UNC and North Carolina State University, Raleigh, NC, United States
| | - Sarah Burnash
- Joint Department of Biomedical Engineering, UNC and North Carolina State University, Raleigh, NC, United States
| | - Rohan R Krishnan
- Joint Department of Biomedical Engineering, UNC and North Carolina State University, Raleigh, NC, United States
| | - Susan Chubinskaya
- Department of Pediatrics, Rush University Medical Center, Chicago, IL, United States
| | - Richard F Loeser
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill (UNC), Chapel Hill, NC, United States; Department of Cell Biology and Physiology, UNC, United States; Division of Rheumatology, Allergy, and Immunology, UNC, United States
| | - William J Polacheck
- Joint Department of Biomedical Engineering, UNC and North Carolina State University, Raleigh, NC, United States; Department of Cell Biology and Physiology, UNC, United States; McAllister Heart Institute, UNC, United States
| | - Brian O Diekman
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill (UNC), Chapel Hill, NC, United States; Joint Department of Biomedical Engineering, UNC and North Carolina State University, Raleigh, NC, United States; Department of Cell Biology and Physiology, UNC, United States.
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5
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Ye X, Li Y, Ma X, Gan L, Huang J. Enhancing Output Signals of Sport Monitors Based on Triboelectric Porous PVDF Nanogenerators via Concaving Cells and Cell-Packing Structures. ACS Appl Bio Mater 2023; 6:4168-4177. [PMID: 37683283 DOI: 10.1021/acsabm.3c00377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/10/2023]
Abstract
Porous triboelectric polymer materials are widely used in portable sensors due to their lightweight and suitable mechanical performance, but their triboelectric properties need to be improved. Here, we propose a two-step strategy to concave the cell and cell-packing structure of triboelectric materials based on porous poly(vinylidene fluoride) (PVDF). The first step is to prepare triboelectric nanogenerators (TENGs) of PVDF with a concave cell-packing structure via oriented phase inversion. The second step is to concave the cells by radial and axial compression. The results reveal that the concavities in the cell structure at the radial direction and in the cell-packing structure at the axial direction improve the output signals of the porous PVDF TENG by ca. 150 and 110%, respectively. By contrast, the concaving in cell structure at the radial direction exerts a positive effect on triboelectric performance only when the radial compression strain is not bigger than 17.5%, especially when the cell wall is thin (ca. 0.85 μm). Meanwhile, the concavity-based strategy eliminates the irreversible deformation behavior of the porous PVDF material, enhancing its elasticity. The stability test shows that the sensor based on those materials is stable under 12,500 cycles, and the variance in the square derivation of output voltage is less than 1% during the cycle friction. Such stable and triboelectric-improved materials are assembled into sports-monitoring devices, providing an idea for the application of TENG in smart sensing.
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Affiliation(s)
- Xian Ye
- School of Chemistry and Chemical Engineering, and Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing, Southwest University, Chongqing 400715, China
- Sichuan Lutianhua Co., Ltd., Chengdu, Sichuan 646300, China
| | - Yanan Li
- School of Chemistry and Chemical Engineering, and Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing, Southwest University, Chongqing 400715, China
| | - Xiaoshuang Ma
- School of Chemistry and Chemical Engineering, and Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing, Southwest University, Chongqing 400715, China
| | - Lin Gan
- School of Chemistry and Chemical Engineering, and Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing, Southwest University, Chongqing 400715, China
| | - Jin Huang
- School of Chemistry and Chemical Engineering, and Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing, Southwest University, Chongqing 400715, China
- School of Chemistry and Chemical Engineering, and Engineering Research Center of Materials-Oriented Chemical Engineering of Xinjiang Bintuan, Shihezi University, Shihezi 832003, China
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6
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Fernandes JV, Pereira AFG, Antunes JM, Chaparro BM, Sakharova NA. Numerical Simulation Study of the Mechanical Behaviour of 1D and 2D Germanium Carbide and Tin Carbide Nanostructures. Materials (Basel) 2023; 16:5484. [PMID: 37570189 PMCID: PMC10419946 DOI: 10.3390/ma16155484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/21/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023]
Abstract
One-dimensional (nanotubes) and two-dimensional (nanosheets) germanium carbide (GeC) and tin carbide (SnC) structures have been predicted and studied only theoretically. Understanding their mechanical behaviour is crucial, considering forthcoming prospects, especially in batteries and fuel cells. Within this framework, the present study aims at the numerical evaluation of the elastic properties, surface Young's and shear moduli and Poisson's ratio, of GeC and SnC nanosheets and nanotubes, using a nanoscale continuum modelling approach. A robust methodology to assess the elastic constants of the GeC and SnC nanotubes without of the need for numerical simulation is proposed. The surface Young's and shear moduli of the GeC and SnC nanotubes and nanosheets are compared with those of their three-dimensional counterparts, to take full advantage of 1D and 2D germanium carbide and tin carbide in novel devices. The obtained outcomes establish a solid basis for future explorations of the mechanical behaviour of 1D and 2D GeC and SnC nanostructures, where the scarcity of studies is evident.
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Affiliation(s)
- José V. Fernandes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.V.F.); (A.F.G.P.); (J.M.A.)
| | - André F. G. Pereira
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.V.F.); (A.F.G.P.); (J.M.A.)
| | - Jorge M. Antunes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.V.F.); (A.F.G.P.); (J.M.A.)
- Abrantes High School of Technology, Polytechnic Institute of Tomar, Quinta do Contador, Estrada da Serra, 2300-313 Tomar, Portugal;
| | - Bruno M. Chaparro
- Abrantes High School of Technology, Polytechnic Institute of Tomar, Quinta do Contador, Estrada da Serra, 2300-313 Tomar, Portugal;
| | - Nataliya A. Sakharova
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.V.F.); (A.F.G.P.); (J.M.A.)
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7
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Yarali E, Zadpoor AA, Staufer U, Accardo A, Mirzaali MJ. Auxeticity as a Mechanobiological Tool to Create Meta-Biomaterials. ACS Appl Bio Mater 2023; 6:2562-2575. [PMID: 37319268 PMCID: PMC10354748 DOI: 10.1021/acsabm.3c00145] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/17/2023] [Indexed: 06/17/2023]
Abstract
Mechanical and morphological design parameters, such as stiffness or porosity, play important roles in creating orthopedic implants and bone substitutes. However, we have only a limited understanding of how the microarchitecture of porous scaffolds contributes to bone regeneration. Meta-biomaterials are increasingly used to precisely engineer the internal geometry of porous scaffolds and independently tailor their mechanical properties (e.g., stiffness and Poisson's ratio). This is motivated by the rare or unprecedented properties of meta-biomaterials, such as negative Poisson's ratios (i.e., auxeticity). It is, however, not clear how these unusual properties can modulate the interactions of meta-biomaterials with living cells and whether they can facilitate bone tissue engineering under static and dynamic cell culture and mechanical loading conditions. Here, we review the recent studies investigating the effects of the Poisson's ratio on the performance of meta-biomaterials with an emphasis on the relevant mechanobiological aspects. We also highlight the state-of-the-art additive manufacturing techniques employed to create meta-biomaterials, particularly at the micrometer scale. Finally, we provide future perspectives, particularly for the design of the next generation of meta-biomaterials featuring dynamic properties (e.g., those made through 4D printing).
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Affiliation(s)
- Ebrahim Yarali
- Department
of Biomechanical Engineering, Faculty of Mechanical Maritime and Materials
Engineering, Delft University of Technology
(TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands
- Department
of Precision and Microsystems Engineering, Faculty of Mechanical Maritime
and Materials Engineering, Delft University
of Technology (TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Amir A. Zadpoor
- Department
of Biomechanical Engineering, Faculty of Mechanical Maritime and Materials
Engineering, Delft University of Technology
(TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Urs Staufer
- Department
of Precision and Microsystems Engineering, Faculty of Mechanical Maritime
and Materials Engineering, Delft University
of Technology (TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Angelo Accardo
- Department
of Precision and Microsystems Engineering, Faculty of Mechanical Maritime
and Materials Engineering, Delft University
of Technology (TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Mohammad J. Mirzaali
- Department
of Biomechanical Engineering, Faculty of Mechanical Maritime and Materials
Engineering, Delft University of Technology
(TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands
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8
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Bertoldo C, Pereira GA, Gonçalves R. Effect of Reducing the Size and Number of Faces of Polyhedral Specimen on Wood Characterization by Ultrasound. Materials (Basel) 2023; 16:4870. [PMID: 37445185 DOI: 10.3390/ma16134870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/26/2023] [Accepted: 07/04/2023] [Indexed: 07/15/2023]
Abstract
The complete characterization of wood, with the determination of the 12 elastic constants that represent its orthotropy, is greatly relevant in applications employing structural calculation software programs. Ultrasound allows for such characterization with relative simplicity when compared to other methods. The polyhedron is considered the most appropriate specimen format for allowing the 12 constants to be calculated with a single specimen, and the traditionally used one is the 26-sided polyhedron, which, to be produced manually with more precision in directing the main directions of the wood, needs larger faces. The accuracy of this technique tends to be reduced when increasing the growth rings' inclination since the waves deviate from the main directions of orthotropy. This research aimed to verify whether it is possible to reduce the polyhedra dimension without affecting the results of the elastic parameters obtained in wood characterization by ultrasound. The results indicate that the dimension of the polyhedron can be reduced without prejudice to the results of the elastic parameters obtained by the ultrasound test and that, in the manual production process of the specimen, the best way to make this reduction is to eliminate the faces unused in the test, changing the polyhedron to 18 faces instead of 26. Reducing the number of faces simplifies the manufacturing process and thus increases the possibility of producing specimens with straighter growth rings and better-directed symmetry axes.
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Affiliation(s)
- Cinthya Bertoldo
- Laboratory of Nondestructive Testing-LabEND, School of Agricultural Engineering-FEAGRI, University of Campinas-UNICAMP, Av. Cândido Rondon, 501-Barão Geraldo, Campinas 13083-875, Brazil
| | - Geise Aparecida Pereira
- Laboratory of Nondestructive Testing-LabEND, School of Agricultural Engineering-FEAGRI, University of Campinas-UNICAMP, Av. Cândido Rondon, 501-Barão Geraldo, Campinas 13083-875, Brazil
| | - Raquel Gonçalves
- Laboratory of Nondestructive Testing-LabEND, School of Agricultural Engineering-FEAGRI, University of Campinas-UNICAMP, Av. Cândido Rondon, 501-Barão Geraldo, Campinas 13083-875, Brazil
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9
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Száva DT, Száva I, Vlase S, Száva A. Experimental Investigations of the Dental Filling Materials: Establishing Elastic Moduli and Poisson's Ratios. Materials (Basel) 2023; 16:ma16093456. [PMID: 37176337 PMCID: PMC10180408 DOI: 10.3390/ma16093456] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/15/2023]
Abstract
The mechanical properties of the dental filling material (DFMs) strongly influence the lifetime and durability of the tooth reparation performed. Among the most significant mechanical characteristics, one has to mention the Poisson's ratio and the elastic modulus (Young's modulus). They, during the cyclic mastication load, can prevent or aid in the prevention of secondary dental decays by provoking micro-cracks, the de-bonding of the filling material from the natural dental tissue, as well as fatigue at the level of their interface. The authors performed a scoping analysis of the nowadays-involved experimental methods, together with a critical review, putting in evidence of their advantages and limits. Based on the developments, they propose a new approach in this sense by involving the electronic speckle pattern interferometry (ESPI)/shearography high-accuracy optical method. They illustrate the advantages of this method in establishment of the elastic modulus, but they also propose a high-accuracy methodology in the estimation of Poisson's ratio. Based on the briefly-illustrated experimental results, one can conclude that ESPI/shearography can become a very useful tool for research, even though it is not a common (nowadays widely applied) method, such as three-point bending or strain gauge methods.
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Affiliation(s)
- Dániel Tamás Száva
- Faculty of Dental Medicine, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, 540142 Targu Mures, Romania
| | - Ioan Száva
- Department of Mechanical Engineering, Transilvania University of Brasov, 500036 Brasov, Romania
| | - Sorin Vlase
- Department of Mechanical Engineering, Transilvania University of Brasov, 500036 Brasov, Romania
- Romanian Academy of Technical Sciences, 030167 Bucharest, Romania
| | - Andrea Száva
- Faculty of Dental Medicine, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, 540142 Targu Mures, Romania
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10
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Sands M, Kim J. A low-cost and open-source measurement system to determine the Young's and shear moduli and Poisson's ratio of soft materials using a Raspberry Pi camera module and 3D printed parts. HardwareX 2023; 13:e00386. [PMID: 36582477 PMCID: PMC9793308 DOI: 10.1016/j.ohx.2022.e00386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/20/2022] [Accepted: 12/08/2022] [Indexed: 06/17/2023]
Abstract
Advances in biomedical and engineering fields have greatly increased the need for understanding of soft structures. Soft materials such as gelatin and gelatin-based hydrogels have grown in popularity for use in a wide variety of applications including tissue engineering, biofabrication, and organ transplantation. With hydrogel structures being used in such demanding applications, it is crucial to properly characterize the dynamic behavior of these soft structures. Although there have been major improvements in measurement technology for determining the mechanical properties of soft, translucent materials, it remains quite challenging to reliably measure the Young's and shear moduli of these materials in a way that remains straightforward, low-cost, and non-contact. This research aims to address the weaknesses in modern measurement methods and develop a system suitable for characterizing the elastic moduli of soft materials that requires only four, inexpensive, off-the-shelf components. Utilizing a Raspberry Pi, stepping motor, and an inexpensive camera, the Young's and shear moduli of a gelatin column is measured five times. The standard deviation between measurement was observed to be less than 0.15% with high accuracy having an error of less than 4.6% when compared to relatively expensive, conventional measurement techniques.
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11
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Zhao G, Fu T. A Unit Compound Structure Design: Poisson's Ratio Is Autonomously Adjustable from Negative to Positive. Materials (Basel) 2023; 16:ma16051808. [PMID: 36902923 PMCID: PMC10004161 DOI: 10.3390/ma16051808] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 02/13/2023] [Accepted: 02/20/2023] [Indexed: 05/27/2023]
Abstract
The shape memory polymer (SMP) is a new type of smart material that can produce a shape memory effect through the stimulation of the external environment. In this article, the viscoelastic constitutive theory of the shape memory polymer and the mechanism of the bidirectional memory effect of the shape memory polymer are described. A chiral poly cellular circular concave auxetic structure based on a shape memory polymer made of epoxy resin is designed. Two structural parameters, α and β, are defined, and the change rule of Poisson's ratio under different structural parameters is verified by ABAQUS. Then, two elastic scaffolds are designed to assist a new type of cellular structure made of a shape memory polymer to autonomously adjust bidirectional memory under the stimulation of the external temperature, and two processes of bidirectional memory are simulated using ABAQUS. Finally, when a shape memory polymer structure implements the bidirectional deformation programming process, a conclusion is drawn that changing the ratio β of oblique ligament and ring radius has a better effect than changing the angle α of oblique ligament and horizontal in achieving the autonomously adjustable bidirectional memory effect of the composite structure. In summary, through the combination of the new cell and the bidirectional deformation principle, the autonomous bidirectional deformation of the new cell is achieved. The research can be used in reconfigurable structures, tuning symmetry, and chirality. The adjusted Poisson's ratio achieved by the stimulation of the external environment can be used in active acoustic metamaterials, deployable devices, and biomedical devices. Meanwhile, this work provides a very meaningful reference for the potential application value of metamaterials.
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Affiliation(s)
| | - Tao Fu
- Correspondence: ; Tel.: +86-18108701527
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12
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Yang Q, Xiang Z, Liu T, Deng C, Zhang H. Study on the Mechanical Properties of Cast-In-Situ Phosphogypsum as Building Material for Structural Walls. Materials (Basel) 2023; 16:1481. [PMID: 36837111 PMCID: PMC9964400 DOI: 10.3390/ma16041481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
The application of cast-in-situ phosphogypsum as the wall material of building structures can greatly reduce the environmental pollution caused by phosphogypsum. Through the uniaxial compression test of cast-in-situ phosphogypsum specimens, the compressive strength of cast-in-situ phosphogypsum is determined, the constitutive relationship of the material is drawn up, and the elastic modulus and Poisson's ratio of the material are determined. The results show that when the strain of the specimen is close to the peak strain, the cast-in-situ phosphogypsum has brittle properties and rapidly fails, where the failure state is mainly splitting failure. The retarder has a great influence on the peak stress. When the content of the retarder is about 0.3%, the peak stress is 8.6 MPa and the ultimate strain is 2.54 × 10-3, while the peak stress is 2.8 MPa and the ultimate strain is 2.01 × 10-3. The three segment constitutive fitted equations reflect all the characteristics of the compression specimen. When the strength of the cast-in-situ phosphogypsum is high, the elastic modulus is also high. When the content of the retarder is about 0.3%, the elastic modulus is 5300 MPa, and when the content of retarder is far greater than 0.3%, the elastic modulus is 2000 MPa. The Poisson's ratio of material is recommended as 0.19.
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Affiliation(s)
- Qizhu Yang
- College of Civil Engineering and Architectural, Shaoyang University, Shaoyang 422000, China
| | - Ze Xiang
- College of Civil Engineering and Architectural, Shaoyang University, Shaoyang 422000, China
| | - Taoyong Liu
- College of Civil Engineering and Architectural, Shaoyang University, Shaoyang 422000, China
| | - Changqing Deng
- College of Civil Engineering and Architectural, Shaoyang University, Shaoyang 422000, China
| | - Huagang Zhang
- Space Structures Research Center, Guizhou University, Guiyang 550025, China
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13
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Hufert J, Grebhardt A, Schneider Y, Bonten C, Schmauder S. Deformation Behavior of 3D Printed Auxetic Structures of Thermoplastic Polymers: PLA, PBAT, and Blends. Polymers (Basel) 2023; 15:389. [PMID: 36679269 DOI: 10.3390/polym15020389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 01/15/2023] Open
Abstract
Auxetic structures have a negative Poisson's ratio and therefore expand transversely to the direction of loading instead of tapering. This unique behavior is not caused by the materials used, but by the structure, and thus offers completely new functionalities and design possibilities. As a rule, auxetic structures have a very complex geometry, which makes cost-effective production possible only by means of additive manufacturing processes. Due to the high design freedom of the strand deposition method, it makes sense to manufacture auxetic structures using this process. Therefore, in this project, polylactide acid (PLA), polybutylene adipate terephthalate (PBAT), and blends of the two polymers were produced and characterized. Filaments of the two polymers and a blend were extruded, processed into auxetic structures by strand deposition process (SDP), and investigated for their properties, primarily their Poisson's ratio. The Poisson's ratio was determined and the influence of the material on it was identified. A specific number of 5 × 5 unit cells has been found to be ideal for investigation. Dual printed specimens showed a similar auxetic behavior as the specimens made of pure PBAT. Likewise, multiple loading and unloading of the structure is possible. Furthermore, in-situ computed tomography revealed the detailed characterization of the initial state, including the warpage of the structures, damage, and traced auxetic behavior in detail.
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14
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Liu S, Du Z. Study on the Tensile Behavior of Helical Auxetic Yarns with Finite Element Method. Materials (Basel) 2022; 16:122. [PMID: 36614460 PMCID: PMC9821531 DOI: 10.3390/ma16010122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/28/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Complex yarns with helical wrapping structure show auxetic effect under axial tension and a wide perspective application. Experimental results suggested that initial helical angle was one of the most important structural parameters. However, the experimental method was limited and could not effectively explain the deformation behavior or auxetic mechanism. A finite element model of the helical auxetic yarn was built and used to analyze the interactive relationship between the two components and the stress distribution mode. The effectiveness and accuracy of the model was first verified by comparing with the experimental results. The simulation results showed that the complex yarn with initial helical angle of 14.5° presented the maximum negative Poisson's ratio of -2.5 under 5.0% axial strain. Both the contact property between the two components and the radial deformability of the elastic core filament were key factors of the auxetic property. When the contact surfaces were completely smooth and the friction coefficient μ was set to 0, the complex yarn presented non-auxetic behavior. When the Poisson's ratio of the core filament was 0, the complex yarn showed greater auxetic effect. During the axial stretching, the tensile stress was mainly distributed in the wrap filament, which led to structural deformation and auxetic behavior. A pair of auxetic yarns showed pore effect and high expansion under axial strain. Thus, it may be necessary to consider new weaving structures and preparation methods to obtain the desired auxetic property and application of auxetic yarns.
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Affiliation(s)
- Sai Liu
- College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Zhaoqun Du
- Engineering Research Center of Technical Textiles, Ministry of Education, Donghua University, Shanghai 201620, China
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15
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Zhang HN, Fan Y, Shen HS. Chirality-Dependent and Intrinsic Auxeticity for Single-Walled Carbon Nanotubes. Materials (Basel) 2022; 15:8720. [PMID: 36556525 PMCID: PMC9785320 DOI: 10.3390/ma15248720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/04/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
Single-walled carbon nanotubes (SWCNTs) have superior mechanical properties which originate from a strong C-C covalent bond and unique nanostructure. Chirality, one of the helical structural parameters of SWCNTs, leads to differences in mechanical performance. In this work, molecular dynamics (MD) simulation was performed to analyze engineering Poisson's ratio (EPR) and incremental Poisson's ratio (IPR) of SWCNTs with different chiral angles, respectively, under tensile and compressive load, as well as the chiral effect on rigidity. We reported the minimum EPR for (4, 1) SWCNT and obtained the distribution and trend of EPR which is dependent on chiral index m. In addition, a new observation showed two exactly opposite trends of EPR existing not only in tension and compression but also in the longitudinal and radial directions. Furthermore, we found that the critical strain, over which SWCNT would be auxetic, ranged from 6% to 18% and was also chirality-dependent. Three representative SWCNTs with chiral angle of 0° (zigzag), 10.89° (chiral), and 30° (armchair) were selected for the mechanism study of auxeticity. Finally, a method of the contribution to radial strain for two main deformation modes proposed in this paper could well explain the negative IPR phenomenon.
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16
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Berladir K, Zhyhylii D, Brejcha J, Pozovnyi O, Krmela J, Krmelová V, Artyukhov A. Computer Simulation of Composite Materials Behavior under Pressing. Polymers (Basel) 2022; 14. [PMID: 36501680 DOI: 10.3390/polym14235288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/28/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
Composite materials have a wide range of functional properties, which is ensured by using various technological methods of obtaining both the matrix or fillers and the composition as a whole. A special place belongs to the composition formation technology, which ensures the necessary structure and properties of the composite. In this work, a computer simulation was carried out to identify the main dependencies of the behavior of composite materials in the process of the main technological operations of their production: pressing and subsequent sintering. A polymer matrix randomly reinforced with two types of fillers: spherical and short cylindrical inclusions, was used to construct the finite element models of the structure of composites. The ANSYS Workbench package was used as a calculation simulation platform. The true stress-strain curves for tension, Poisson's ratios, and ultimate stresses for composite materials were obtained using the finite element method based on the micromechanical approach at the first stage. These values were calculated based on the stretching diagrams of the matrix and fillers and the condition of the ideality of their joint operation. At the second stage, the processes of mechanical pressing of composite materials were modelled based on their elastic-plastic characteristics from the first stage. The result is an assessment of the accumulation of residual strains at the stage before sintering. The degree of increase in total strain capability of composite materials after sintering was shown.
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17
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Zhou C, Zhang H, Yuan X, Song K, Liu D. Applicability of Pre-Plastic Deformation Method for Improving Mechanical Properties of Bulk Metallic Glasses. Materials (Basel) 2022; 15:7574. [PMID: 36363165 PMCID: PMC9654271 DOI: 10.3390/ma15217574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 10/19/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Pre-plastic deformation (PPD) treatments on bulk metallic glasses (BMGs) have previously been shown to be helpful in producing multiple shear bands. In this work, the applicability of the PPD approach on BMGs with different Poisson's ratios was validated based on experimental and simulation observations. It was found that for BMGs with high Poisson's ratios (HBMGs, e.g., Zr56Co28Al16 and Zr46Cu46Al8), the PPD treatment can easily trigger a pair of large plastic deformation zones consisting of multiple shear bands. These PPD-treated HBMGs clearly display improved strength and compressive plasticity. On the other hand, the mechanical properties of BMGs with low Poisson's ratios (LBMG, e.g., Fe48Cr15Mo14Y2C15B6) become worse due to a few shear bands and micro-cracks in extremely small plastic deformation zones. Additionally, for the PPD-treated HBMGs with similar high Poisson's ratios, the Zr56Co28Al16 BMG exhibits much larger plasticity than the Zr46Cu46Al8 BMG. This phenomenon is mainly due to more defective icosahedral clusters in the Zr56Co28Al16 BMG, which can serve as nucleation sites for shear transformation zones (STZs) during subsequent deformation. The present study may provide a basis for understanding the plastic deformation mechanism of BMGs.
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Affiliation(s)
- Changshan Zhou
- Shenzhen Research Institute of Shandong University, Shenzhen 518057, China
- School of Mechanical, Electrical and Information Engineering, Shandong University, Weihai 264209, China
| | - Hezhi Zhang
- Shenzhen Research Institute of Shandong University, Shenzhen 518057, China
- School of Mechanical, Electrical and Information Engineering, Shandong University, Weihai 264209, China
| | - Xudong Yuan
- Shenzhen Research Institute of Shandong University, Shenzhen 518057, China
- Department of Materials Science, University of Leoben, A-8700 Leoben, Austria
| | - Kaikai Song
- Shenzhen Research Institute of Shandong University, Shenzhen 518057, China
- School of Mechanical, Electrical and Information Engineering, Shandong University, Weihai 264209, China
| | - Dan Liu
- Weihai Wanfeng Magnesium Industry Science and Technology Development Co., Ltd., Weihai 264209, China
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18
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Wang L, Chen Y, Miura H, Suzuki K, Wang C. Penta-graphene and phagraphene: thermal expansion, linear compressibility, and Poisson's ratio. J Phys Condens Matter 2022; 34:505301. [PMID: 36265479 DOI: 10.1088/1361-648x/ac9c3e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
Nonplanar penta-graphene and planar phagraphene, which are connected by carbon pentagons and penta-hexa-hepta carbon rings, respectively, are two allotropes of graphene. Graphene as a star material in two-dimensional materials has been widely studied. However, the studies around penta-graphene and phagraphene are still insufficient. We are interested in both materials' response to temperature, hydrostatic pressure, and stress. In this work, the thermal expansion, linear compressibility, and Poisson's ratio of penta-graphene and phagraphene have been investigated systematically. It is found that both materials can exhibit abnormal negative thermal expansion behavior, while their linear compressibility behavior is normal. The negative Poisson's ratio behavior only occurs in penta-graphene, which is consistent with other work. Through an analysis of the lattice vibrations and associated mode Grüneisen parameters, it is found that there are anomalies in the phonon spectra of both penta-graphene and phagraphene. It is noted that acoustic phonons contribute most to their respective anomalies, especially the transverse acoustic mode. The librational motion of the lowest-frequency optical phonon of both materials is identified and also associated with their novel properties. In general, the unique topological arrangement of carbon atoms can play a decisive role in determining the performances of penta-graphene and phagraphene.
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Affiliation(s)
- Lei Wang
- Department of Physics, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
| | - Ying Chen
- Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Hideo Miura
- Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Ken Suzuki
- Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Cong Wang
- School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
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19
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Han Z, Xiao X, Chen J, Wei K, Wang Z, Yang X, Fang D. Bifunctional Metamaterials Incorporating Unusual Geminations of Poisson's Ratio and Coefficient of Thermal Expansion. ACS Appl Mater Interfaces 2022; 14:50068-50078. [PMID: 36283006 DOI: 10.1021/acsami.2c11702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Natural materials overwhelmingly shrink laterally under stretching and expand upon heating. Through incorporating Poisson's ratio and coefficient of thermal expansion (PR and CTE) in unusual geminations, such as positive PR and negative CTE, negative PR and positive CTE, and even zero PR and zero CTE, bifunctional metamaterials would generate attractive shape control capacity. However, reported bifunctional metamaterials are only theoretically constructed by simple skeletal ribs, and the magnitudes of the bifunctions are still in quite narrow ranges. Here, we propose a methodology for generating novel bifunctional metamaterials consisting of engineering polymers. From concept to refinement, the topology and shape optimization are integrated for programmatically designing bifunctional metamaterials in various germinations of the PR and CTE. The underlying deformation mechanisms of the obtained bifunctions are distinctly revealed. All of the designs with complex architectures and material layouts are fabricated using the multimaterial additive manufacturing, and their effective properties are experimentally characterized. Good agreements of the design, simulation, and experiments are achieved. Especially, the accessible range of the bifunction, namely, PR and CTE, is remarkably enlarged nearly 4 times. These developed approaches open an avenue to explore the bifunctional metamaterials, which are the basis of myriad mechanical- and temperature-sensitive devices, e.g., morphing structures and high-precision components of the sensors/actuators in aerospace and electronical domains.
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Affiliation(s)
- Zhengtong Han
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan410082, People's Republic of China
| | - Xiaoyujie Xiao
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan410082, People's Republic of China
| | - Jiaxin Chen
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan410082, People's Republic of China
| | - Kai Wei
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan410082, People's Republic of China
- State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha, Hunan410083, People's Republic of China
| | - Zhonggang Wang
- State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha, Hunan410083, People's Republic of China
| | - Xujing Yang
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan410082, People's Republic of China
| | - Daining Fang
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing100081, People's Republic of China
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20
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Liu S, Chen H, Li Y, Du Z. Design, Manufacture, and Characterization of Auxetic Yarns with Multiple Core/Wrap Structure by Braiding Method. Materials (Basel) 2022; 15:6300. [PMID: 36143612 PMCID: PMC9505242 DOI: 10.3390/ma15186300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 09/05/2022] [Accepted: 09/07/2022] [Indexed: 06/16/2023]
Abstract
Auxetic textiles with a negative Poisson's ratio show significant energy absorption and synclastic curvature characteristics and potential application value in sportsmen protection material. The stability and reliability of the structure and properties of auxetic textiles is also an important factor to assess and promote the application. Thus, auxetic yarns with multiple core/wrap structure were prepared by a 16-spindle braiding machine. It mainly focused on the axial stretching behavior and the relationship between the structure and auxetic effect of yarn samples. The maximum Poisson's ratio of auxetic yarns was -3.26. The experimental results also showed that the complex yarns still presented an auxetic effect during 30 repeats of cycle stretching. According to the study about the repeatable stretchability and auxetic effect of complex yarns, it could be expected to provide more comfortable, safer, and smarter protective textiles.
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Affiliation(s)
- Sai Liu
- College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Haoyu Chen
- College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Yizhu Li
- College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Zhaoqun Du
- Engineering Research Center of Technical Textiles, Ministry of Education, Donghua University, Shanghai 201620, China
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21
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Yin Y, Liu G, Zhao T, Ma Q, Wang L, Zhang Y. Inversion Method of the Young's Modulus Field and Poisson's Ratio Field for Rock and Its Test Application. Materials (Basel) 2022; 15:5463. [PMID: 35955395 PMCID: PMC9369481 DOI: 10.3390/ma15155463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/05/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
As one typical heterogeneous material, the heterogeneity of rock micro parameters has an important effect on its macro mechanical behavior. The study of the heterogeneity of micro parameters is more important to reveal the root cause of deformation and failure. However, as a typical heterogeneous material, the current testing and inversion method is not suitable for micro parameters measurement for the rock. Aiming at obtaining the distribution of micro Young's modulus and micro Poisson's ratio of the rock, based on the digital image correlation method (DIC) and finite element method (FEM), this paper proposed a parameter field inversion method, namely the DF-PF inversion method. Its inversion accuracy is verified using numerical simulation and laboratory uniaxial compression test. Considering the influences of heterogeneity, stress state and dimension difference, the average inversion error of Young's modulus field and Poisson's ratio field are below 10%, and the proportion of elements with an error of less than 15% accounts for more than 86% in the whole specimen model. Compared with the conventional measuring method, the error of macro Young's modulus and macro Poisson's ratio calculated by the DF-PF inversion method is less than 2.8% and 9.07%, respectively. Based on the statistical analysis of Young's modulus field and Poisson's ratio field, the parameter homogeneity and quantitative function relation between the micro parameter and the principal strain can also be obtained in laboratory tests. The DF-PF inversion method provides a new effective method of testing Young's modulus field and Poisson's ratio field of the rocks under complex stress states.
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Affiliation(s)
- Yanchun Yin
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
- College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, China
| | - Guangyan Liu
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Tongbin Zhao
- College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, China
| | - Qinwei Ma
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Lu Wang
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yubao Zhang
- College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, China
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22
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Ali S. Elastic Properties and Hardness of Mixed Alkaline Earth Silicate Oxynitride Glasses. Materials (Basel) 2022; 15:ma15145022. [PMID: 35888488 PMCID: PMC9320866 DOI: 10.3390/ma15145022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/11/2022] [Accepted: 07/17/2022] [Indexed: 11/16/2022]
Abstract
The incorporation of nitrogen as a second anion species into oxide glasses offers unique opportunities for modifying glass properties via changes in glass polymerization and structure. In this work, the compositional dependence of elastic properties and the nanoindentation hardness of mixed alkaline-earth silicate oxynitride glasses containing a high amount of nitrogen (>15 at.%, c.a. 35 e/o) were investigated. Three series of silicon oxynitride glass compositions AE−Ca−Si−O−N glasses (where AE = Mg, Sr, and Ba) having varying amounts of modifiers were prepared using a new glass synthesis route, in which a precursor powder of metal hydrides was used. The obtained glasses contained high amounts of N (19 at.%, c.a. 43 e/o) and modifier cations (26 at.%, c.a. 39 e/o). Mg−Ca−Si−O−N glasses had high values of nanohardness (12−16 GPa), along with a reduced elastic modulus (130−153 GPa) and Young’s modulus (127−146 GPa), in comparison with the Sr−Ca- and Ba−Ca-bearing oxynitride glasses. Both the elastic modulus and the nanohardness of AE−Ca−Si−O−N glasses decreased with an increase in the atomic number of the AE element. These property changes followed a linear dependence on the effective cation field strength (ECFS) of the alkaline earth (AE) modifier, according to their valences and ionic radii. No mixed alkaline-earth effect was observed in the current investigation, indicating that the properties were more dictated by the nitrogen content.
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Affiliation(s)
- Sharafat Ali
- Department of Built Environment and Energy Technology, School of Engineering, Linnæus University, SE-351 95 Växjö, Sweden
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23
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Xia H, Meng J, Liu J, Ao X, Lin S, Yang Y. Evaluation of the Equivalent Mechanical Properties of Lattice Structures Based on the Finite Element Method. Materials (Basel) 2022; 15:2993. [PMID: 35591329 PMCID: PMC9104921 DOI: 10.3390/ma15092993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 12/31/2022]
Abstract
Lattice structures have excellent mechanical properties and can be designed by changing the cellular structure. However, the computing scale is extremely large to directly analyze a large-size structure containing a huge number of lattice cells. Evaluating the equivalent mechanical properties instead of the complex geometry of such lattice cells is a feasible way to deal with this problem. This paper aims to propose a series of formulas, including critical structural and material parameters, to fast evaluate the equivalent mechanical properties of lattice structures. A reduced-order model based on the finite element method and beam theory was developed and verified by comparing it with the corresponding full model. This model was then applied to evaluate the equivalent mechanical properties of 25 types of lattice cells. The effects of the material Young's modulus and Poisson's ratio, strut diameter, cell size, and cell number on those equivalent mechanical properties were investigated and discussed, and the linear relationship with the material parameters and the non-linear relationship with the structural parameters were found. Finally, a series of analytical-fitting formulas involving the structural and material parameters were obtained, which allows us to fast predict the equivalent mechanical properties of the lattice cells.
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Affiliation(s)
- Huanxiong Xia
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; (H.X.); (J.M.); (J.L.); (S.L.)
- Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314000, China
| | - Junfeng Meng
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; (H.X.); (J.M.); (J.L.); (S.L.)
| | - Jianhua Liu
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; (H.X.); (J.M.); (J.L.); (S.L.)
- Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314000, China
| | - Xiaohui Ao
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; (H.X.); (J.M.); (J.L.); (S.L.)
| | - Shengxiang Lin
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; (H.X.); (J.M.); (J.L.); (S.L.)
| | - Ye Yang
- School of Mechanical and Material Engineering, North China University of Technology, Beijing 100144, China;
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24
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Persson AMMR, Andreassen E. Cyclic Compression Testing of Three Elastomer Types-A Thermoplastic Vulcanizate Elastomer, a Liquid Silicone Rubber and Two Ethylene-Propylene-Diene Rubbers. Polymers (Basel) 2022; 14:polym14071316. [PMID: 35406192 PMCID: PMC9002981 DOI: 10.3390/polym14071316] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/17/2022] [Accepted: 03/21/2022] [Indexed: 02/04/2023] Open
Abstract
Thermoplastic elastomer vulcanizate (TPV) and liquid silicone rubber (LSR) are replacement candidates for ethylene-propylene-diene rubbers (EPDM), as they offer the possibility for two-component injection moulding. In this study, these material types were compared side by side in cyclic compression tests. The materials were also characterized to provide details on the formulations. Compared to the rubbers, the TPV had higher compression set (after a given cycle) and hysteresis loss, and a stronger Mullins effect. This is due to the thermoplastic matrix in the TPV. The LSR had lower compression set (after a given cycle) than the EPDM, but stronger Mullins effect and higher relative hysteresis loss. These differences between the LSR and the EPDM are likely due to differences in polymer network structure and type of filler. Methods for quantifying the Mullins effect are proposed, and correlations between a Mullins index and parameters such as compression set are discussed. The EPDMs showed a distinct trend in compression set, relative hysteresis loss and relaxed stress fraction vs. strain amplitude; these entities were almost independent of strain amplitude in the range 15-35%, while they increased in this range for the TPV and the LSR. The difference between the compression set values of the LSR and the EPDM decreased with increasing strain amplitude and increasing strain recovery time.
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Affiliation(s)
- Anna-Maria Märta Ruth Persson
- Dept. of Manufacturing and Civil Engineering, NTNU, P.O. Box 191, 2802 Gjøvik, Norway
- Polymer and Composite Materials Group, SINTEF Industry, P.O. Box 124 Blindern, 0314 Oslo, Norway
- Correspondence: (A.-M.M.R.P.); (E.A.)
| | - Erik Andreassen
- Polymer and Composite Materials Group, SINTEF Industry, P.O. Box 124 Blindern, 0314 Oslo, Norway
- Correspondence: (A.-M.M.R.P.); (E.A.)
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Bate B, Chen X, Chen C, Ma H, Zhu J, Cao J, Chen J, Khayat KH, Zhang S. Setting Times of Early-Age Mortars Determined from Evolution Curves of Poisson's Ratio. Materials (Basel) 2022; 15:853. [PMID: 35160797 DOI: 10.3390/ma15030853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/14/2021] [Accepted: 12/18/2021] [Indexed: 11/20/2022]
Abstract
Setting times, as the early-age properties of cement-based materials, are important properties to ensure the quality and long-term performance of engineering structures. To determine the initial and final setting times of cementitious materials, the compressive wave velocity and shear wave velocity of six early-age mortar samples were monitored. Their time evolution curves of Young’s modulus, shear modulus, bulk modulus, and Poisson’s ratio were then calculated and analyzed. The signature times of the derivatives of the Poisson’s ratio evolution curves correlate well with the initial and final setting times, and the remarkably high coefficient of determination values relative to the data from this study are higher than those presented in the current literature. The proposed derivative method on the Poisson’s ratio evolution curve is as good as the derivative methods from vs. evolution curves used by prior studies for the estimation of both the initial and final setting times of the early-age properties of cement-based materials. The formation and subsequent disappearance of ettringite of low Poisson’s ratio were postulated to cause the initial dip in the Poisson’s ratio evolution curves.
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Tevet O, Svetlizky D, Harel D, Barkay Z, Geva D, Eliaz N. Measurement of the Anisotropic Dynamic Elastic Constants of Additive Manufactured and Wrought Ti6Al4V Alloys. Materials (Basel) 2022; 15:ma15020638. [PMID: 35057356 PMCID: PMC8779917 DOI: 10.3390/ma15020638] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/11/2022] [Accepted: 01/11/2022] [Indexed: 02/04/2023]
Abstract
Additively manufactured (AM) materials and hot rolled materials are typically orthotropic, and exhibit anisotropic elastic properties. This paper elucidates the anisotropic elastic properties (Young's modulus, shear modulus, and Poisson's ratio) of Ti6Al4V alloy in four different conditions: three AM (by selective laser melting, SLM, electron beam melting, EBM, and directed energy deposition, DED, processes) and one wrought alloy (for comparison). A specially designed polygon sample allowed measurement of 12 sound wave velocities (SWVs), employing the dynamic pulse-echo ultrasonic technique. In conjunction with the measured density values, these SWVs enabled deriving of the tensor of elastic constants (Cij) and the three-dimensional (3D) Young's moduli maps. Electron backscatter diffraction (EBSD) and micro-computed tomography (μCT) were employed to characterize the grain size and orientation as well as porosity and other defects which could explain the difference in the measured elastic constants of the four materials. All three types of AM materials showed only minor anisotropy. The wrought (hot rolled) alloy exhibited the highest density, virtually pore-free μCT images, and the highest ultrasonic anisotropy and polarity behavior. EBSD analysis revealed that a thin β-phase layer that formed along the elongated grain boundaries caused the ultrasonic polarity behavior. The finding that the elastic properties depend on the manufacturing process and on the angle relative to either the rolling direction or the AM build direction should be taken into account in the design of products. The data reported herein is valuable for materials selection and finite element analyses in mechanical design. The pulse-echo measurement procedure employed in this study may be further adapted and used for quality control of AM materials and parts.
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Affiliation(s)
- Ofer Tevet
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel; (O.T.); (D.S.); (D.H.)
- Materials Department, Nuclear Research Center Negev (NRCN), Beer Sheva 84190, Israel
| | - David Svetlizky
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel; (O.T.); (D.S.); (D.H.)
| | - David Harel
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel; (O.T.); (D.S.); (D.H.)
| | - Zahava Barkay
- The Wolfson Applied Materials Research Centre, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel;
| | - Dolev Geva
- Israel Ministry of Defense, Hakirya, Tel Aviv 61909, Israel;
| | - Noam Eliaz
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel; (O.T.); (D.S.); (D.H.)
- Correspondence: ; Tel.: +972-3-640-7384
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Ferretti E, Moretti M, Chiusoli A, Naldoni L, De Fabritiis F, Visonà M. Mechanical Properties of a 3D-Printed Wall Segment Made with an Earthen Mixture. Materials (Basel) 2022; 15:438. [PMID: 35057156 PMCID: PMC8778666 DOI: 10.3390/ma15020438] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/02/2022] [Accepted: 01/05/2022] [Indexed: 12/02/2022]
Abstract
This study provides a contribution to the research field of 3D-printed earthen buildings, focusing, for the first time, on the load-bearing capacity of these structures. The study involves the entire production and testing process of the earthen elements, from the design, to the preparation of the mixture and the 3D printing, up to the uniaxial compression test on a wall segment. The results indicate that 3D-printed earthen elements have a compressive strength of 2.32 MPa, comparable to that of rammed earth structures. The experimental data also made it possible to draw conclusions on the action of the infill, which seems to have the function of stopping the propagation of cracks. This has a positive effect on the overall behavior of 3D-printed earthen elements, since it avoids the onset of dilative behavior in the final stages of the load test and maintains ultimate load values higher than 50% of the maximum load.
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Affiliation(s)
- Elena Ferretti
- Department of Civil, Environmental and Materials Engineering—DICAM, Alma Mater Studiorum Università di Bologna, Viale del Risorgimento 2, 40136 Bologna, Italy
| | - Massimo Moretti
- WASP s.r.l., Via Castelletto 104/106, 48024 Massa Lombarda, Italy; (M.M.); (A.C.); (L.N.); (F.D.F.); (M.V.)
| | - Alberto Chiusoli
- WASP s.r.l., Via Castelletto 104/106, 48024 Massa Lombarda, Italy; (M.M.); (A.C.); (L.N.); (F.D.F.); (M.V.)
| | - Lapo Naldoni
- WASP s.r.l., Via Castelletto 104/106, 48024 Massa Lombarda, Italy; (M.M.); (A.C.); (L.N.); (F.D.F.); (M.V.)
| | - Francesco De Fabritiis
- WASP s.r.l., Via Castelletto 104/106, 48024 Massa Lombarda, Italy; (M.M.); (A.C.); (L.N.); (F.D.F.); (M.V.)
| | - Massimo Visonà
- WASP s.r.l., Via Castelletto 104/106, 48024 Massa Lombarda, Italy; (M.M.); (A.C.); (L.N.); (F.D.F.); (M.V.)
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Carvajal L, Sosa M, Artigas A, Luco N, Monsalve A. Ultrasonic Assessment of the Influence of Cold Rolling and Recrystallization Annealing on the Elastic Constants in a TWIP Steel. Materials (Basel) 2021; 14:6559. [PMID: 34772081 DOI: 10.3390/ma14216559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/27/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022]
Abstract
The evolution of the elastic constants, C33, C44 and C55, Poisson’s ratio and acoustic birefringence of a Fe-0.5 wt% C-21.5 wt% Mn twinning-induced plasticity (TWIP) steel with reduction by cold rolling and recrystallization annealing was assessed from measurements of the times of flight of ultrasonic waves propagating along the thickness of the rolled plates. As the reduction increased, changes in the elastic constants resulted in a steadily increasing orthotropy, which was clearly shown by Poisson’s ratio and acoustic birefringence. Although optical metallography and hardness measurements showed that partial or full recrystallization is attained after annealing at 600 °C and 700 °C, the ultrasonic measurements revealed that a high level of orthotropy remains.
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Yan Q, Weng J, Shen S, Wang Y, Fang M, Zheng G, Yang Q, Yang G. Finite Element Analysis for Biodegradable Dissolving Microneedle Materials on Skin Puncture and Mechanical Performance Evaluation. Polymers (Basel) 2021; 13:polym13183043. [PMID: 34577944 PMCID: PMC8467965 DOI: 10.3390/polym13183043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/31/2021] [Accepted: 09/07/2021] [Indexed: 11/16/2022] Open
Abstract
In this study, a micro-molding technology was used to prepare the microneedles (MNs), while a texture analyzer was used to measure its Young’s modulus, Poisson’s ratio and compression breaking force, to evaluate whether the MNs can penetrate the skin. The effects of different materials were characterized by their ability to withstand stresses using the Structural Mechanics Module of COMSOL Multiphysics. Carboxymethylcellulose (CMC) was chosen as the needle formulation material with varying quantities of polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA) and hyaluronic acid (HA) to adjust the viscosity, brittleness, hardness and solubility of the material. The results of both the experimental tests and the predictions indicated that the hardest tip material had a solids content of 15% (w/w
) with a 1:2 (w/w) CMC: HA ratio. Furthermore, it was shown that a solid content of 10% (w/w) with a 1:5 (w/w) CMC: PVA ratio is suitable for making patches. The correlation between the mechanical properties and the different materials was found using the simulation analysis as well as the force required for different dissolving microneedles (DMNs) to penetrate the skin, which significantly promoted the research progress of microneedle transdermal drug delivery.
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Mina AL, Trezos KG, Petrou MF. Optimizing the Mechanical Properties of Ultra-High-Performance Fibre-Reinforced Concrete to Increase Its Resistance to Projectile Impact. Materials (Basel) 2021; 14:5098. [PMID: 34501188 PMCID: PMC8434575 DOI: 10.3390/ma14175098] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/28/2021] [Accepted: 08/31/2021] [Indexed: 11/16/2022]
Abstract
This study describes an extensive experimental investigation of various mechanical properties of Ultra-High-Performance Fibre-Reinforced Concrete (UHPFRC). The scope is to achieve high strength and ductile behaviour, hence providing optimal resistance to projectile impact. Eight different mixtures were produced and tested, three mixtures of Ultra-High-Performance Concrete (UHPC) and five mixtures of UHPFRC, by changing the amount and length of the steel fibres, the quantity of the superplasticizer, and the water to binder (w/b) ratio. Full stress-strain curves from compression, direct tension, and flexural tests were obtained from one batch of each mixture to examine the influence of the above parameters on the mechanical properties. The Poisson's ratio and modulus of elasticity in compression and direct tension were measured. Additionally, a factor was determined to convert the cubic strength to cylindrical. Based on the test results, the mixture with high volume (6%) and a combination of two lengths of steel fibres (3% each), water to binder ratio of 0.16% and 6.1% of superplasticizer to binder ratio exhibited the highest strength and presented great deformability in the plastic region. A numerical simulation developed using ABAQUS was capable of capturing very well the experimental three-point bending response of the UHPFRC best-performed mixture.
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Affiliation(s)
- Anna L. Mina
- Laboratory of Reinforced Concrete, School of Civil Engineering, National Technical University of Athens, 5 Iroon Polytechniou Street, 15773 Zografou, Greece;
- Department of Civil and Environmental Engineering, University of Cyprus, 75 Kallipoleos Avenue, P.O. Box 20537, Nicosia 1678, Cyprus;
| | - Konstantinos G. Trezos
- Laboratory of Reinforced Concrete, School of Civil Engineering, National Technical University of Athens, 5 Iroon Polytechniou Street, 15773 Zografou, Greece;
| | - Michael F. Petrou
- Department of Civil and Environmental Engineering, University of Cyprus, 75 Kallipoleos Avenue, P.O. Box 20537, Nicosia 1678, Cyprus;
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Xu YX, Juang JY. Measurement of Nonlinear Poisson's Ratio of Thermoplastic Polyurethanes under Cyclic Softening Using 2D Digital Image Correlation. Polymers (Basel) 2021; 13:1498. [PMID: 34066636 DOI: 10.3390/polym13091498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 04/29/2021] [Accepted: 05/04/2021] [Indexed: 02/07/2023] Open
Abstract
Thermoplastic polyurethanes (TPUs) and other elastomers are widely used in many applications for the advantages they provide in terms of high elasticity, lightness, resistance to breakage, and impact resistance. These materials exhibit strong hysteresis in the large strain stress-strain behavior, known as cyclic softening or the Mullins effect. Despite the extensive studies on this phenomenon and the importance of Poisson’s ratio, how the Poisson’s ratio of these materials changes during cyclic uniaxial tests is still unclear. Here, we measure the nonlinear Poisson’s ratio of TPU and investigate its correlation with cyclic softening using two-dimensional digital image correlation (2D-DIC) combined with the reference sample compensation (RSC) method. This accuracy-enhanced method can effectively eliminate the measurement errors induced by the unavoidable out-of-plane displacements and lens distortion. We find that the Poisson’s ratio of TPUs also exhibits large hysteresis in the first cycle and then approaches a steady state in subsequent cycles. Specifically, it starts from a relatively low value of 0.45 ± 0.005 in the first loading, then increases to 0.48 ± 0.005 in the first unloading, and remains largely constant afterward. Such a change in the Poisson’s ratio results in a slight volume increase (≈1%) at a maximum strain of 17.5%. Our findings are useful for those who use finite element method to analyze the mechanical behavior of TPU, and shed new light on understanding the physical origin of cyclic softening.
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Tang A, Ji J, Li J, Liu W, Wang J, Sun Q, Li Q. Nanocellulose/PEGDA Aerogels with Tunable Poisson's Ratio Fabricated by Stereolithography for Mouse Bone Marrow Mesenchymal Stem Cell Culture. Nanomaterials (Basel) 2021; 11:603. [PMID: 33670932 DOI: 10.3390/nano11030603] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 02/20/2021] [Accepted: 02/23/2021] [Indexed: 12/24/2022]
Abstract
In this study, nanocellulose aerogels with a tunable Poisson's ratio were fabricated. Tissue engineering scaffolds with a tunable Poisson's ratio may be better able to simulate the mechanical behavior of natural tissues. A mixture of cellulose nanofibers (CNFs) and polyethylene glycol diacrylate (PEGDA) was used as the raw material to prepare CNF/PEGDA aerogels with a multiscale pore structure through a combination of stereolithography (SLA) and freeze-drying. The aerogels were fabricated with a regular macropore network structure and a random and homogeneous distribution of micropores. The macropore structure of the scaffolds could be customized through SLA, which resulted in scaffolds that exhibited one of three different mechanical behaviors: positive Poisson's ratio (PPR), negative Poisson's ratio (NPR) or zero Poisson's ratio (ZPR). Then, the hydrogel scaffolds were transformed into aerogel scaffolds through the freeze-drying method, which endowed the scaffolds with homogeneously distributed micropores. The material ratio and exposure were adjusted to obtain scaffolds with a clear pore structure. Then, the CNF/PEGDA scaffolds with different Poisson's ratios were subjected to mechanical tests, and their chondrogenic induction characteristics were determined. The NPR scaffold not only provided a good environment for cell growth but also affected mouse bone marrow mesenchymal stem cell (mBMSC) proliferation and chondrogenic induction. Thus, we provide a feasible scheme for the preparation of three-dimensional scaffolds with a multiscale pore structure and tunable Poisson's ratio, which contributes to cartilage repair in tissue engineering.
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Dudek KK, Gatt R, Dudek MR, Grima JN. Controllable Hierarchical Mechanical Metamaterials Guided by the Hinge Design. Materials (Basel) 2021; 14:758. [PMID: 33562783 PMCID: PMC7914626 DOI: 10.3390/ma14040758] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 01/27/2021] [Accepted: 02/02/2021] [Indexed: 11/17/2022]
Abstract
In this work, we use computer simulations (Molecular Dynamics) to analyse the behaviour of a specific auxetic hierarchical mechanical metamaterial composed of square-like elements. We show that, depending on the design of hinges connecting structural elements, the system can exhibit a controllable behaviour where different hierarchical levels can deform to the desired extent. We also show that the use of different hinges within the same structure can enhance the control over its deformation and mechanical properties, whose results can be applied to other mechanical metamaterials. In addition, we analyse the effect of the size of the system as well as the variation in the stiffness of its hinges on the range of the exhibited auxetic behaviour (negative Poisson's ratio). Finally, it is discussed that the concept presented in this work can be used amongst others in the design of highly efficient protective devices capable of adjusting their response to a specific application.
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Affiliation(s)
- Krzysztof K. Dudek
- Institute of Physics, University of Zielona Gora, ul. Szafrana 4a, 65-069 Zielona Gora, Poland;
| | - Ruben Gatt
- Metamaterials Unit, Faculty of Science, University of Malta, Msida, MSD 2080, Malta; (R.G.); (J.N.G.)
- Centre for Molecular Medicine and Biobanking, University of Malta, Msida, MSD 2080, Malta
| | - Miroslaw R. Dudek
- Institute of Physics, University of Zielona Gora, ul. Szafrana 4a, 65-069 Zielona Gora, Poland;
| | - Joseph N. Grima
- Metamaterials Unit, Faculty of Science, University of Malta, Msida, MSD 2080, Malta; (R.G.); (J.N.G.)
- Department of Chemistry, Faculty of Science, University of Malta, Msida, MSD 2080, Malta
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Eskandari F, Rahmani Z, Shafieian M. The effect of large deformation on Poisson's ratio of brain white matter: An experimental study. Proc Inst Mech Eng H 2020; 235:401-407. [PMID: 33357009 DOI: 10.1177/0954411920984027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A more Accurate description of the mechanical behavior of brain tissue could improve the results of computational models. While most studies have assumed brain tissue as an incompressible material with constant Poisson's ratio of almost 0.5 and constructed their modeling approach according to this assumption, the relationship between this ratio and levels of applied strains has not yet been studied. Since the mechanical response of the tissue is highly sensitive to the value of Poisson's ratio, this study was designed to investigate the characteristics of the Poisson's ratio of brain tissue at different levels of applied strains. Samples were extracted from bovine brain tissue and tested under unconfined compression at strain values of 5%, 10%, and 30%. Using an image processing method, the axial and transverse strains were measured over a 60-s period to calculate the Poisson's ratio for each sample. The results of this study showed that the Poisson's ratio of brain tissue at strain levels of 5% and 10% was close to 0.5, and assuming brain tissue as an incompressible material is a valid assumption at these levels of strain. For samples under 30% compression, this ratio was higher than 0.5, which could suggest that under strains higher than the brain injury threshold (approximately 18%), tissue integrity was impaired. Based on these observations, it could be concluded that for strain levels higher than the injury threshold, brain tissue could not be assumed as an incompressible material, and new material models need to be proposed to predict the material behavior of the tissue. In addition, the results showed that brain tissue under unconfined compression uniformly stretched in the transverse direction, and the bulging in the samples is negligible.
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Affiliation(s)
- Faezeh Eskandari
- Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
| | - Zahra Rahmani
- Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
| | - Mehdi Shafieian
- Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
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LI G, ZHANG Y, SCHINDEL GM, FIELD MS, GOLDSCHEIDER N. RAYLEIGH WAVE AND WELL HEAD RESPONSE TO CALCULATE POROSITY IN THE EDWARDS AQUIFER OF SOUTH-CENTRAL TEXAS, USA. Acta Carsologica 2020; 49:241-253. [PMID: 35548323 PMCID: PMC9088069 DOI: 10.3986/ac.v49i2-3.8849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We use the magnitude and centroid period of Rayleigh wave along with the amplitude of fluctuations of water level in a well to calculate effective porosity of a karst aquifer at the site scale. The radial and vertical displacements of Rayleigh wave are first related to the confining pressure of rock, which is then related to fluid pressure via the Gassmann equation. Three seismograms recorded at station 633A of the USARRAY and the induced responses of Well J-17 in the Edwards Aquifer (Texas) allow the calculation of an effective porosity between 17.0 and 24.4 percent, the average of which is close to the total porosity of core samples determined by geophysical well logs. This paper provides an innovative method to measure effective porosity in aquifers. Because of the long wavelengths of Rayleigh wave, the interdisciplinary approach is advantageous in that the resulting effective porosity is at the site scale which includes large conduits or voids.
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Affiliation(s)
- Guangquan LI
- Department of Geophysics, Chenggong Campus, Yunnan University, Kunming, Yunnan 650504 P. R. China
| | - Yunpeng ZHANG
- Institute of Geophysics, Earthquake Administration of China, Beijing, China 100081
| | | | - Malcolm S. FIELD
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment (8623R), 1200 Pennsylvania, Ave., N.W., Washington, D.C. 20460
| | - Nico GOLDSCHEIDER
- Karlsruhe Institute of Technology (KIT), Institute of Applied Geosciences, Division of Hydrogeology, D-76131 Karlsruhe, Germany
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Abstract
We consider disordered solids in which the microscopic elements can deform plastically in response to stresses on them. We show that by driving the system periodically, this plasticity can be exploited to train in desired elastic properties, both in the global moduli and in local "allosteric" interactions. Periodic driving can couple an applied "source" strain to a "target" strain over a path in the energy landscape. This coupling allows control of the system's response, even at large strains well into the nonlinear regime, where it can be difficult to achieve control simply by design.
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Wang H, Wang L, Li L, Cheng B, Zhang Y, Wei Y. The Study on the Whole Stress-Strain Curves of Coral Fly Ash-Slag Alkali-Activated Concrete under Uniaxial Compression. Materials (Basel) 2020; 13:ma13194291. [PMID: 32992951 PMCID: PMC7579447 DOI: 10.3390/ma13194291] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/18/2020] [Accepted: 09/23/2020] [Indexed: 11/16/2022]
Abstract
This study aimed to research the whole stress–strain curves of coral Fly Ash-Slag Alkali-Activated Concrete (CAAC) in different strength grades. Fly ash-slag alkali-activated concrete was used as cementing materials to produce coral aggregate concrete. A monotonic loading test was conducted on the prismatic specimens to obtain elastic modulus (Ec), Poisson’s ratio (μ) and the constitutive relationship of CAAC under uniaxial compression. When the strain of CAAC reached the maximum value, the specimen was split and damaged rapidly. As the strength grade increased, the ratio of residual stress (σri) to peak stress (σ0i) decreased in the range of 0.17–0.28. The Ec of CAAC increased gradually, and μ increased to the peak value and then decreased. According to the test results, the constitutive equation of CAAC can be expressed by piecewise expression, which can better reflect all the experimental characteristics. It was also found that CAAC has many similar characteristics with coral concrete and lightweight aggregate concrete. To improve the strength and toughness of CAAC, some fibers, such as organic fiber, can be added to expand the application of CAAC in engineering projects.
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Affiliation(s)
- Huailiang Wang
- College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China; (H.W.); (L.W.)
- Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education, Nanning 530004, China
| | - Lang Wang
- College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China; (H.W.); (L.W.)
| | - Lei Li
- School of civil engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China;
| | - Baoquan Cheng
- School of Civil Engineering, Central South University, Changsha 410083, China
- Correspondence:
| | - Yonggang Zhang
- Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China;
| | - Yuhu Wei
- College of Civil Engineering, Anhui Jianzhu University, Hefei 230000, China;
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Østergaard MB, Bødker MS, Smedskjaer MM. Structure Dependence of Poisson's Ratio in Cesium Silicate and Borate Glasses. Materials (Basel) 2020; 13:E2837. [PMID: 32599913 DOI: 10.3390/ma13122837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/12/2020] [Accepted: 06/22/2020] [Indexed: 12/22/2022]
Abstract
In glass materials, Poisson’s ratio (ν) has been proposed to be correlated with a variety of features, including atomic packing density (Cg), liquid fragility (m), and network connectivity. To further investigate these correlations in oxide glasses, here, we study cesium borate and cesium silicate glasses with varying modifier/former ratio given the difference in network former coordination and because cesium results in relatively high ν compared to the smaller alkali modifiers. Within the binary glass series, we find positive correlations between ν on one hand and m and Cg on the other hand. The network former is found to greatly influence the correlation between ν and the number of bridging oxygens (nBO), with a negative correlation for silicate glasses and positive correlation for borate glasses. An analysis based on topological constraint theory shows that this difference cannot be explained by the effect of superstructural units on the network connectivity in lithium borate glasses. Considering a wider range of oxide glasses from the literature, we find that ν generally decreases with increasing network connectivity, but with notable exceptions for heavy alkali borate glasses and calcium alumino tectosilicate glasses.
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Nguyen TT, Phan DH, Mai HH, Nguyen DL. Investigation on Compressive Characteristics of Steel-Slag Concrete. Materials (Basel) 2020; 13:E1928. [PMID: 32325853 DOI: 10.3390/ma13081928] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/12/2020] [Accepted: 04/15/2020] [Indexed: 11/16/2022]
Abstract
The compressive characteristics of the steel-slag concrete were investigated through an experimental test. The term “steel-slag concrete” in this research work was defined as a kind of concrete using steel-slag material as a coarse aggregate replacement. Three types of the steel-slag concretes were examined under compression as follows: XT01, XT02, XT03 with their cement/water ratios of 1.76, 2.00, 2.21, respectively. The coarse aggregate used in producing concrete was steel-slag material, while the fine aggregate was traditional river sand; the ratio of coarse aggregate to fine aggregate was kept constant at a value of 1.98. Firstly, the age-dependent compressive strength of the steel-slag concretes were investigated up to one year; it was clear that the concrete strength increased rapidly in 7 days, then more and more slowly after that. Secondly, the modulus of elasticity and Poisson’s ratio of the steel-slag concretes were explored at the 28-day age. Thirdly, there was an important size and shape effect on the compressive strength of the XT02, and its significance of brittleness in failure was analytically analyzed. Lastly, the effects of water amount added in the XT02 on its compressive strength and slump were evaluated at the 28-day age.
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Cappello J, d’Herbemont V, Lindner A, du Roure O. Microfluidic In-Situ Measurement of Poisson's Ratio of Hydrogels. Micromachines (Basel) 2020; 11:E318. [PMID: 32204340 PMCID: PMC7142615 DOI: 10.3390/mi11030318] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 01/02/2023]
Abstract
Being able to precisely characterize the mechanical properties of soft microparticles is essential for numerous situations, from the understanding of the flow of biological fluids to the development of soft micro-robots. Here, we present a simple measurement technique for determining Poisson's ratio of soft micron-sized hydrogels in the presence of a surrounding liquid. This method relies on the measurement of the deformation, in two orthogonal directions, of a rectangular hydrogel slab compressed uni-axially inside a microfluidic channel. Due to the in situ character of the method, the sample does not need to be dried, allowing for the measurement of the mechanical properties of swollen hydrogels. Using this method, we determined Poisson's ratio of hydrogel particles composed of polyethylene glycol (PEG) and varying solvents fabricated using a lithography technique. The results demonstrate, with high precision, the dependence of the hydrogel compressibility on the solvent fraction and character. The method is easy to implement and can be adapted for the measurement of a variety of soft and biological materials.
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Affiliation(s)
| | | | - Anke Lindner
- Laboratoire PMMH-ESPCI Paris, PSL Research University, Sorbonne Université, Université de Paris, 10, rue Vauquelin, F-75005 Paris, France; (J.C.); (V.d.); (O.d.R.)
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Cabras L, Brun M, Misseroni D. Micro-structured medium with large isotropic negative thermal expansion. Proc Math Phys Eng Sci 2019; 475:20190468. [PMID: 31892835 DOI: 10.1098/rspa.2019.0468] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 11/18/2019] [Indexed: 11/12/2022] Open
Abstract
A challenge in nano- and micro-mechanics is the realization of innovative materials exploiting auxetic behaviour to tailor thermal expansion properties. For this purpose, a new class of micro-structured media possessing an extremely wide range of tunable (positive, negative or even zero) thermal expansion is proposed and analytically and experimentally assessed. For this class of isotropic Mechanical-Auxetic Thermal-Shrinking media, the effective coefficient of thermal expansion is explicitly linked to two microstructural variables via a simple relation, allowing the design with desired values. The theoretical predictions for the negative thermal properties are fully validated by the experimental and numerical outcomes. The simplicity of the proposed structure makes the design useful for the production of a new generation of advanced media, with applications ranging from micromechanical devices to large civil and space structures.
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Affiliation(s)
- Luigi Cabras
- Dipartimento di Ingegneria Meccanica e Industriale, Universitá di Brescia, via Branze 38, Brescia, 25123, Italy
| | - Michele Brun
- Dipartimento di Ingegneria Meccanica, Chimica e dei Materiali, Universitá di Cagliari, via Marengo 2, Cagliari, 09123, Italy
| | - Diego Misseroni
- Dipartimento di Ingegneria Civile, Ambientale e Meccanica, Universitá di Trento, via Mesiano 77, 38123 Trento, Italy
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Ahmadi Moghaddam H, Mertiny P. Stochastic Finite Element Analysis Framework for Modelling Mechanical Properties of Particulate Modified Polymer Composites. Materials (Basel) 2019; 12:E2777. [PMID: 31470532 PMCID: PMC6747834 DOI: 10.3390/ma12172777] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/11/2019] [Accepted: 08/22/2019] [Indexed: 12/28/2022]
Abstract
Polymers have become indispensable in many engineering applications because of their attractive properties, including low volumetric mass density and excellent resistance to corrosion. However, polymers typically lack in mechanical, thermal, and electrical properties that may be required for certain engineering applications. Therefore, researchers have been seeking to improve properties by modifying polymers with particulate fillers. In the research presented herein, a numerical modeling framework was employed that is capable of predicting the properties of binary or higher order composites with randomly distributed fillers in a polymer matrix. Specifically, mechanical properties, i.e., elastic modulus, Poisson's ratio, and thermal expansion coefficient, were herein explored for the case of size-distributed spherical filler particles. The modeling framework, employing stochastic finite element analysis, reduces efforts for assessing material properties compared to experimental work, while increasing the level of accuracy compared to other available approaches, such as analytical methods. Results from the modeling framework are presented and contrasted with findings from experimental works available in the technical literature. Numerical predictions agree well with the non-linear trends observed in the experiments, i.e., elastic modulus predictions are within the experimental data scatter, while numerical data deviate from experimental Poisson's ratio data for filler volume fractions greater than 0.15. The latter may be the result of morphology changes in specimens at higher filler volume fractions that do not comply with modelling assumptions.
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Affiliation(s)
| | - Pierre Mertiny
- Department of Mechanical Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada.
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Dobnik Dubrovski P, Novak N, Borovinšek M, Vesenjak M, Ren Z. In-Plane Behavior of Auxetic Non-Woven Fabric Based on Rotating Square Unit Geometry under Tensile Load. Polymers (Basel) 2019; 11:polym11061040. [PMID: 31212820 PMCID: PMC6630407 DOI: 10.3390/polym11061040] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/03/2019] [Accepted: 06/10/2019] [Indexed: 11/27/2022] Open
Abstract
This paper reports the auxetic behavior of modified conventional non-woven fabric. The auxetic behavior of fabric was achieved by forming rotating square unit geometry with a highly ordered pattern of slits by laser cutting. Two commercial needle-punched non-woven fabric used as lining and the reinforcement fabric for the footwear industry were investigated. The influence of two rotating square unit sizes was analyzed for each fabric. The original and modified fabric samples were subjected to quasi-static tensile load by using the Tinius Olsen testing machine to observe the in-plane mechanical properties and deformation behavior of tested samples. The tests were recorded with a full high-definition (HD) digital camera and the video recognition technique was applied to determine the Poisson’s ratio evolution during testing. The results show that the modified samples exhibit a much lower breaking force due to induced slits, which in turn limits the application of such modified fabric to low tensile loads. The samples with smaller rotating cell sizes exhibit the highest negative Poisson’s ratio during tensile loading through the entire longitudinal strain range until rupture. Non-woven fabric with equal distribution and orientation of fibers in both directions offer better auxetic response with a smaller out-of-plane rotation of rotating unit cells. The out-of-plane rotation of unit cells in non-homogenous samples is higher in machine direction.
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Affiliation(s)
- Polona Dobnik Dubrovski
- Institute of Engineering Materials and Design, Faculty of Mechanical Engineering, University of Maribor, Maribor 2000, Slovenia.
| | - Nejc Novak
- Mechanical Engineering Research Institute, Faculty of Mechanical Engineering, University of Maribor, Maribor 2000, Slovenia.
| | - Matej Borovinšek
- Mechanical Engineering Research Institute, Faculty of Mechanical Engineering, University of Maribor, Maribor 2000, Slovenia.
| | - Matej Vesenjak
- Mechanical Engineering Research Institute, Faculty of Mechanical Engineering, University of Maribor, Maribor 2000, Slovenia.
| | - Zoran Ren
- Mechanical Engineering Research Institute, Faculty of Mechanical Engineering, University of Maribor, Maribor 2000, Slovenia.
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Choi BJ, Yoon S, Im YW, Lee JH, Jung HJ, Lee HH. Uniaxial/biaxial flexure strengths and elastic properties of resin-composite block materials for CAD/CAM. Dent Mater 2018; 35:389-401. [PMID: 30527587 DOI: 10.1016/j.dental.2018.11.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 11/18/2018] [Accepted: 11/28/2018] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Comparing strengths under different loading conditions provides useful information on the mechanical behaviour of restorative materials under multiaxial masticatory loading in the oral cavity. The aims of this study was to investigate the flexural strengths and the reliability of resin-composite blocks for CAD/CAM by uniaxial and biaxial flexure tests and to compare the elastic properties measured by different methods including digital image correlation (DIC). METHODS Four resin-composite blocks for CAD/CAM, namely, VE (Vita Enamic), LU (Lava Ultimate), MD (Mazic Duro), and CS (Cerasmart), were investigated. Beam specimens (4.0×1.4×18.0mm3) and disks (12-14mmϕ×1.5mm) were prepared to determine the uniaxial (three-point bending) and biaxial (ball-on-ring, BOR) flexural strengths and flexural moduli. A compression test (8×4×18mm3) with DIC analysis was utilized to measure the elastic modulus and Poisson's ratio. Data were analysed by a 2-parameter Weibull function and ANOVA with Scheffe's test. RESULTS The mean uniaxial and biaxial strengths and Weibull moduli of the specimen groups were as follows: uniaxial VE (140.1±7.0, 24.1), LU (159.1±6.3, 31.5), MD (144.9±13.3, 13.6), and CS (165.4±16.9, 11.2) and biaxial VE (153.6±10.4, 19.0), LU (231.0±29.3, 9.7), MD (148.9±23.8, 7.4), and CS (249.7±22.4, 13.8). Although the ranking of both sets of strength data remained unchanged, the strength reliability was significantly affected by the loading; the Weibull moduli of the specimens decreased when they were subjected to biaxial tests (except for that of CS). The elastic modulus values of the materials varied significantly under the different test loadings, although they were in the same order regardless of the test method: VE>>LU≈MD>CS. The DIC technique yielded elastic moduli that were in good agreement with those measured by the uniaxial flexure test. SIGNIFICANCE The flexural strength, reliability, and elastic modulus of resin-composite block materials differed with the uniaxial and biaxial flexural loading and the test method. The different behaviours under both loadings should be considered in the evaluation of the mechanical performance of those materials.
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Affiliation(s)
- Beom-Jin Choi
- Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 31116, South Korea
| | - Sungsik Yoon
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
| | - Yong-Woon Im
- Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 31116, South Korea; Department of Dental Laboratory, Kyungdong University, Wonju 26495, South Korea
| | - Jung-Hwan Lee
- Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 31116, South Korea; Institute of Tissue Regeneration Engineering, Dankook University, Cheonan 31116, South Korea
| | - Hyung-Jo Jung
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
| | - Hae-Hyoung Lee
- Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 31116, South Korea; Institute of Tissue Regeneration Engineering, Dankook University, Cheonan 31116, South Korea.
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Kováčik J, Marsavina L, Linul E. Poisson's Ratio of Closed-Cell Aluminium Foams. Materials (Basel) 2018; 11:ma11101904. [PMID: 30301257 PMCID: PMC6213076 DOI: 10.3390/ma11101904] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/01/2018] [Accepted: 10/03/2018] [Indexed: 11/16/2022]
Abstract
A nondestructive impulse excitation technique was used to investigate Poisson's ratio of powder metallurgical pure closed-cell aluminium foams according to ASTM E 1876 within the foam density range of 0.430⁻1.390 g·cm-3. Instead of a constant value of 0.34, as according to Gibson and Ashby's assumption for the Poisson's ratio of metallic foams, the decrease of the Poisson's ratio with decreasing foam density was observed. Observed Poisson's ratio data were in the range of 0.21⁻0.34. To check the validity of the results, the Young's modulus was calculated using Poisson's ratio and its dependence on relative density was successfully modelled using the usual power law function with characteristic exponent of 1.72 ± 0.1. This confirms that the obtained experimental results for Poisson's ratio are valid. Finally, rule of mixture and percolation theory were used to model the observed decrease of Poisson's ratio with increasing porosity.
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Affiliation(s)
- Jaroslav Kováčik
- Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Dúbravskácesta 9, 845 13 Bratislava, Slovak Republic.
| | - Liviu Marsavina
- Department of Mechanics and Strength of Materials, Politehnica University of Timisoara, 1 Mihai Viteazu Avenue, 300 222 Timisoara, Romania.
| | - Emanoil Linul
- Department of Mechanics and Strength of Materials, Politehnica University of Timisoara, 1 Mihai Viteazu Avenue, 300 222 Timisoara, Romania.
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Chen S, Guan C, Ke S, Zeng X, Huang C, Hu S, Yen F, Huang H, Lu Y, Chen L. Modulation of Abnormal Poisson's Ratios and Electronic Properties in Mixed-Valence Perovskite Manganite Films. ACS Appl Mater Interfaces 2018; 10:18029-18035. [PMID: 29745233 DOI: 10.1021/acsami.7b19580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Epitaxy and misfit strain imposed by underlying substrates have been intensively used to tailor the microstructure and electronic properties of oxide films, but this approach is largely restricted by commercially limited substrates. In contrast to the conventional epitaxial misfit strains with a positive Poisson's constant, we show here a tunable Poisson's ratio with anomalous values from negative, zero, to positive. This permits effective control over the out-of-plane lattice parameters that strongly correlate the magnetic and transport properties in perovskite mixed-valence La1- xSr xMnO3 thin films. Our results provide an unconventional approach to better modulation and understanding of elastic-mediated microstructures and physical properties of oxide films by engineering the Poisson's ratios.
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Affiliation(s)
- Shanquan Chen
- Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering , Shenzhen University , Nanshan District, Shenzhen , 518060 Guangdong , China
| | - Changxin Guan
- Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering , Shenzhen University , Nanshan District, Shenzhen , 518060 Guangdong , China
- Department of Physics , Southern University of Science and Technology , Nanshan District, Shenzhen , 518055 Guangdong , China
- Department of Materials Science and Engineering , Hubei University , Wuchang District, 430062 Hubei , China
| | - Shanming Ke
- Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering , Shenzhen University , Nanshan District, Shenzhen , 518060 Guangdong , China
| | - Xierong Zeng
- Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering , Shenzhen University , Nanshan District, Shenzhen , 518060 Guangdong , China
| | - Chuanwei Huang
- Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering , Shenzhen University , Nanshan District, Shenzhen , 518060 Guangdong , China
- Department of Physics , Southern University of Science and Technology , Nanshan District, Shenzhen , 518055 Guangdong , China
| | - Sixia Hu
- Department of Physics , Southern University of Science and Technology , Nanshan District, Shenzhen , 518055 Guangdong , China
| | - Fei Yen
- Department of Physics , Southern University of Science and Technology , Nanshan District, Shenzhen , 518055 Guangdong , China
| | - Haoliang Huang
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230026 , P. R. China
| | - Yalin Lu
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230026 , P. R. China
| | - Lang Chen
- Department of Physics , Southern University of Science and Technology , Nanshan District, Shenzhen , 518055 Guangdong , China
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Lührs L, Zandersons B, Huber N, Weissmüller J. Plastic Poisson's Ratio of Nanoporous Metals: A Macroscopic Signature of Tension-Compression Asymmetry at the Nanoscale. Nano Lett 2017; 17:6258-6266. [PMID: 28872883 DOI: 10.1021/acs.nanolett.7b02950] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The suggestion, based on atomistic simulation, of a surface-induced tension-compression asymmetry of the strength and flow stress of small metal bodies so far lacks experimental confirmation. Here, we present the missing experimental evidence. We study the transverse plastic flow of nanoporous gold under uniaxial compression. Performing mechanical tests in electrolyte affords control over the surface state. Specifically, the surface tension, γ, can be varied in situ during plastic flow. We find that decreasing γ leads to an increase of the effective macroscopic plastic Poisson ratio, νP. Finite element simulations of a network with surface tension confirm the notion that νP of nanoporous gold provides a signature for a local tension-compression asymmetry of the nanoscale struts that form the network. We show that γ promotes compression while impeding tensile elongation. Because the transverse strain is partly carried by the elongation of ligaments oriented normal to the load axis, the surface-induced tension-compression asymmetry acts to reduce νP. Our experiment confirms a decisive contribution of the surface tension to small-scale plasticity.
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Affiliation(s)
- Lukas Lührs
- Institute of Materials Physics and Technology, Hamburg University of Technology , 21073 Hamburg, Germany
| | - Birthe Zandersons
- Institute of Materials Physics and Technology, Hamburg University of Technology , 21073 Hamburg, Germany
| | - Norbert Huber
- Institute of Materials Physics and Technology, Hamburg University of Technology , 21073 Hamburg, Germany
- Institute of Materials Research, Materials Mechanics, Helmholtz-Zentrum Geesthacht , 21502 Geesthacht, Germany
| | - Jörg Weissmüller
- Institute of Materials Physics and Technology, Hamburg University of Technology , 21073 Hamburg, Germany
- Institute of Materials Research, Materials Mechanics, Helmholtz-Zentrum Geesthacht , 21502 Geesthacht, Germany
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Ramaiah BJ, Ramana GV. Study of stress-strain and volume change behavior of emplaced municipal solid waste using large-scale triaxial testing. Waste Manag 2017; 63:366-379. [PMID: 28139366 DOI: 10.1016/j.wasman.2017.01.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 01/16/2017] [Accepted: 01/17/2017] [Indexed: 06/06/2023]
Abstract
The article presents the stress-strain and volume change behavior, shear strength and stiffness parameters of landfilled municipal solid waste (MSW) collected from two dump sites located in Delhi, India. Over 30 drained triaxial compression (TXC) tests were conducted on reconstituted large-scale specimens of 150mm diameter to study the influence of fiber content, age, density and confining pressure on the shear strength of MSW. In addition, a few TXC tests were also conducted on 70mm diameter specimen to examine the effect of specimen size on the mobilized shear strength. It is observed that the fibrous materials such as textiles and plastics, and their percentage by weight have a significant effect on the stress-strain-volume change behavior, shear strength and stiffness of solid waste. The stress-strain-volume change behavior of MSW at Delhi is qualitatively in agreement with the behavior reported for MSW from different countries. Results of large-scale direct shear tests conducted on MSW with an identical composition used for TXC tests revealed the cross-anisotropic behavior as reported by previous researchers. Effective shear strength parameters of solid waste evaluated from this study is best characterized by ϕ'=39° and c'=0kPa for the limiting strain-based failure criteria of K0=0.3+5% axial strain and are in the range of the data reported for MSW from different countries. Data presented in this article is useful for the stress-deformation and stability analysis of the dump sites during their operation as well as closure plans.
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Affiliation(s)
- B J Ramaiah
- Civil Engineering Department, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
| | - G V Ramana
- Civil Engineering Department, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
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Yan Y, Li Y, Song L, Zeng C, Li Y. Pluripotent stem cell expansion and neural differentiation in 3-D scaffolds of tunable Poisson's ratio. Acta Biomater 2017; 49:192-203. [PMID: 27845272 DOI: 10.1016/j.actbio.2016.11.025] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 11/06/2016] [Accepted: 11/10/2016] [Indexed: 12/15/2022]
Abstract
Biophysical properties of the scaffolds such as the elastic modulus, have been recently shown to impact stem cell lineage commitment. On the other hand, the contribution of the Poisson's ratio, another important biophysical property, to the stem cell fate decision, has not been studied. Scaffolds with tunable Poisson's ratio (ν) (termed as auxetic scaffolds when Poisson's ratio is zero or negative) are anticipated to provide a spectrum of unique biophysical 3-D microenvironments to influence stem cell fate. To test this hypothesis, in the present work we fabricated auxetic polyurethane scaffolds (ν=0 to -0.45) and evaluated their effects on neural differentiation of mouse embryonic stem cells (ESCs) and human induced pluripotent stem cells (hiPSCs). Compared to the regular scaffolds (ν=+0.30) before auxetic conversion, the auxetic scaffolds supported smaller aggregate formation and higher expression of β-tubulin III upon neural differentiation. The influences of pore structure, Poisson's ratio, and elastic modulus on neural lineage commitment were further evaluated using a series of auxetic scaffolds. The results indicate that Poisson's ratio may confound the effects of elastic modulus, and auxetic scaffolds with proper pore structure and Poisson's ratio enhance neural differentiation. This study demonstrates that tuning the Poisson's ratio of the scaffolds together with elastic modulus and microstructure would enhance the capability to generate broader, more diversified ranges of biophysical 3-D microenvironments for the modulation of cellular differentiation. STATEMENT OF SIGNIFICANCE Biophysical signaling from the substrates and scaffolds plays a critical role in neural lineage commitment of pluripotent stem cells. While the contribution of elastic modulus has been well studied, the influence of Poisson's ratio along with microstructure of the scaffolds remains unknown largely due to the lack of technology to produce materials with tailorable Poisson's ratio. This study fabricated auxetic polyurethane scaffolds with different elastic modulus, Poisson's ratio and microstructure and evaluated neural differentiation of pluripotent stem cells. The findings add a novel angle to understand the impact of biophysical microenvironment on stem cell fate decisions.
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50
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Zhang X, Yang D. Mechanical Properties of Auxetic Cellular Material Consisting of Re-Entrant Hexagonal Honeycombs. Materials (Basel) 2016; 9:ma9110900. [PMID: 28774021 PMCID: PMC5457195 DOI: 10.3390/ma9110900] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 10/17/2016] [Accepted: 11/02/2016] [Indexed: 11/29/2022]
Abstract
A preliminary study of the mechanical properties of auxetic cellular material consisting of re-entrant hexagonal honeycombs is presented. For different scales of the honeycombs, the finite element method (FEM) and experimental models are used to perform a parametric analysis on the effects of the Poisson’s ratio (cell angle) and the relative density (cell thickness) of honeycombs on bearing capacity and dynamic performance of the auxetic material. The analysis demonstrates that the ultimate bearing capacity of the presented auxetic cellular material is scale-independent when the Poisson’s ratio and the relative density are kept constant. The relationship between the geometric parameters and vibration level difference of the honeycombs is also revealed, which can be divided into two converse parts around the Poisson’s ratio v=−1.5. When v is smaller than −1.5, increasing the cell thickness leads to an increase in the vibration level difference of the honeycombs. Moreover, the dynamic performance of thin-walled honeycombs is greatly influenced by the scale of the honeycombs, especially for the ones with small Poisson’s ratio. These conclusions are verified by a frequency response test and a good agreement between the numerical results and experimental data is achieved.
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Affiliation(s)
- Xiangwen Zhang
- State Key Laboratory of Ocean Engineering, Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Deqing Yang
- State Key Laboratory of Ocean Engineering, Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
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