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Clauß F, Epple N, Ahrens MA, Niederleithinger E, Mark P. Correlation of Load-Bearing Behavior of Reinforced Concrete Members and Velocity Changes of Coda Waves. MATERIALS 2022; 15:ma15030738. [PMID: 35160683 PMCID: PMC8837117 DOI: 10.3390/ma15030738] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/10/2022] [Accepted: 01/17/2022] [Indexed: 11/16/2022]
Abstract
The integral collection of information such as strains, cracks, or temperatures by ultrasound offers the best prerequisites to monitor structures during their lifetime. In this paper, a novel approach is proposed which uses the collected information in the coda of ultrasonic signals to infer the condition of a structure. This approach is derived from component tests on a reinforced concrete beam subjected to four-point bending in the lab at Ruhr University Bochum. In addition to ultrasonic measurements, strain of the reinforcement is measured with fiber optic sensors. Approached by the methods of moment-curvature relations, the steel strains serve as a reference for velocity changes of the coda waves. In particular, a correlation between the relative velocity change and the average steel strain in the reinforcement is derived that covers 90 % of the total bearing capacity. The purely empirical model yields a linear function with a high level of accuracy (R2=0.99, RMSE≈90μstrain).
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Affiliation(s)
- Felix Clauß
- Institute of Concrete Structures, Faculty of Civil and Environmental Engineering, Ruhr University Bochum, Universitätstraße 150, 44801 Bochum, Germany; (M.A.A.); (P.M.)
- Correspondence:
| | - Niklas Epple
- Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin, Germany; (N.E.); (E.N.)
| | - Mark Alexander Ahrens
- Institute of Concrete Structures, Faculty of Civil and Environmental Engineering, Ruhr University Bochum, Universitätstraße 150, 44801 Bochum, Germany; (M.A.A.); (P.M.)
| | - Ernst Niederleithinger
- Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin, Germany; (N.E.); (E.N.)
| | - Peter Mark
- Institute of Concrete Structures, Faculty of Civil and Environmental Engineering, Ruhr University Bochum, Universitätstraße 150, 44801 Bochum, Germany; (M.A.A.); (P.M.)
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Global Wave Velocity Change Measurement of Rock Material by Full-Waveform Correlation. SENSORS 2021; 21:s21227429. [PMID: 34833505 PMCID: PMC8621158 DOI: 10.3390/s21227429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/03/2021] [Accepted: 11/05/2021] [Indexed: 11/25/2022]
Abstract
Measuring accurate wave velocity change is a crucial step in damage assessment of building materials such as rock and concrete. The anisotropy caused by the generation of cracks in the damage process and the uncertainty of the damage level of these building materials make it difficult to obtain accurate wave velocity change. We propose a new method to measure the wave velocity change of anisotropic media at any damage level by full-waveform correlation. In this method, the anisotropy caused by the generation of cracks in the damage process is considered. The accuracy of the improved method is verified by numerical simulation and compared with the existing methods. Finally, the proposed method is applied to measure the wave velocity change in the damage process of rock under uniaxial compression. We monitor the failure process of rock by acoustic emission (AE) monitoring system. Compared with the AE ringing count, the result of damage evaluation obtained by the proposed method is more accurate than the other two methods in the stage of increasing rock heterogeneity. These results show that the proposed method is feasible in damage assessment of building materials such as rock and concrete.
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Grabke S, Clauß F, Bletzinger KU, Ahrens MA, Mark P, Wüchner R. Damage Detection at a Reinforced Concrete Specimen with Coda Wave Interferometry. MATERIALS 2021; 14:ma14175013. [PMID: 34501101 PMCID: PMC8433964 DOI: 10.3390/ma14175013] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 08/26/2021] [Accepted: 08/29/2021] [Indexed: 11/16/2022]
Abstract
Reinforced concrete is a widely used construction material in the building industry. With the increasing age of structures and higher loads there is an immense demand for structural health monitoring of built infrastructure. Coda wave interferometry is a possible candidate for damage detection in concrete whose applicability is demonstrated in this study. The technology is based on a correlation evaluation of two ultrasonic signals. In this study, two ways of processing the correlation data for damage detection are compared. The coda wave measurement data are obtained from a four-point bending test at a reinforced concrete specimen that is also instrumented with fibre optic strain measurements. The used ultrasonic signals have a central frequency of 60 kHz which is a significant difference to previous studies. The experiment shows that the coda wave interferometry has a high sensitivity for developing cracks and by solving an inverse problem even multiple cracks can be distinguished. A further specialty of this study is the use of finite elements for solving a diffusion problem which is needed to state the previously mentioned inverse problem for damage localization.
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Affiliation(s)
- Stefan Grabke
- Chair of Structural Analysis, TU München, Arcisstraße 21, 80333 München, Germany; (K.-U.B.); (R.W.)
- Correspondence:
| | - Felix Clauß
- Chair of Concrete Structures, Ruhr-Universität Bochum, Universitaätstraße 150, 44801 Bochum, Germany; (F.C.); (M.A.A.); (P.M.)
| | - Kai-Uwe Bletzinger
- Chair of Structural Analysis, TU München, Arcisstraße 21, 80333 München, Germany; (K.-U.B.); (R.W.)
| | - Mark Alexander Ahrens
- Chair of Concrete Structures, Ruhr-Universität Bochum, Universitaätstraße 150, 44801 Bochum, Germany; (F.C.); (M.A.A.); (P.M.)
| | - Peter Mark
- Chair of Concrete Structures, Ruhr-Universität Bochum, Universitaätstraße 150, 44801 Bochum, Germany; (F.C.); (M.A.A.); (P.M.)
| | - Roland Wüchner
- Chair of Structural Analysis, TU München, Arcisstraße 21, 80333 München, Germany; (K.-U.B.); (R.W.)
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Finger C, Saydak L, Vu G, Timothy JJ, Meschke G, Saenger EH. Sensitivity of Ultrasonic Coda Wave Interferometry to Material Damage-Observations from a Virtual Concrete Lab. MATERIALS (BASEL, SWITZERLAND) 2021; 14:4033. [PMID: 34300952 PMCID: PMC8307069 DOI: 10.3390/ma14144033] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/12/2021] [Accepted: 07/15/2021] [Indexed: 11/24/2022]
Abstract
Ultrasonic measurements are used in civil engineering for structural health monitoring of concrete infrastructures. The late portion of the ultrasonic wavefield, the coda, is sensitive to small changes in the elastic moduli of the material. Coda Wave Interferometry (CWI) correlates these small changes in the coda with the wavefield recorded in intact, or unperturbed, concrete specimen to reveal the amount of velocity change that occurred. CWI has the potential to detect localized damages and global velocity reductions alike. In this study, the sensitivity of CWI to different types of concrete mesostructures and their damage levels is investigated numerically. Realistic numerical concrete models of concrete specimen are generated, and damage evolution is simulated using the discrete element method. In the virtual concrete lab, the simulated ultrasonic wavefield is propagated from one transducer using a realistic source signal and recorded at a second transducer. Different damage scenarios reveal a different slope in the decorrelation of waveforms with the observed reduction in velocities in the material. Finally, the impact and possible generalizations of the findings are discussed, and recommendations are given for a potential application of CWI in concrete at structural scale.
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Affiliation(s)
- Claudia Finger
- Fraunhofer IEG, Fraunhofer Research Institution for Energy Infrastructures and Geothermal Systems, Am Hochschulcampus 1, 44801 Bochum, Germany;
- Institute for Geology, Mineralogy and Geophysics, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum, Germany;
| | - Leslie Saydak
- Institute for Geology, Mineralogy and Geophysics, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum, Germany;
- Reservoir Engineering and Rock Physics, Bochum University of Applied Sciences, Am Hochschulcampus 1, 44801 Bochum, Germany
| | - Giao Vu
- Institute for Structural Mechanics, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum, Germany; (G.V.); (J.J.T.); (G.M.)
| | - Jithender J. Timothy
- Institute for Structural Mechanics, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum, Germany; (G.V.); (J.J.T.); (G.M.)
| | - Günther Meschke
- Institute for Structural Mechanics, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum, Germany; (G.V.); (J.J.T.); (G.M.)
| | - Erik H. Saenger
- Fraunhofer IEG, Fraunhofer Research Institution for Energy Infrastructures and Geothermal Systems, Am Hochschulcampus 1, 44801 Bochum, Germany;
- Institute for Geology, Mineralogy and Geophysics, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum, Germany;
- Reservoir Engineering and Rock Physics, Bochum University of Applied Sciences, Am Hochschulcampus 1, 44801 Bochum, Germany
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