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Fischer VKS, Rothschild MA, Kneubuehl BP, Kamphausen T. Skin simulants for wound ballistic investigation - an experimental study. Int J Legal Med 2024:10.1007/s00414-024-03223-1. [PMID: 38570340 DOI: 10.1007/s00414-024-03223-1] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 03/22/2024] [Indexed: 04/05/2024]
Abstract
Gunshot wound analysis is an important part of medicolegal practice, in both autopsies and examinations of living persons. Well-established and studied simulants exist that exhibit both physical and biomechanical properties of soft-tissues and bones. Current research literature on ballistic wounds focuses on the biomechanical properties of skin simulants. In our extensive experimental study, we tested numerous synthetic and natural materials, regarding their macromorphological bullet impact characteristics, and compared these data with those from real bullet injuries gathered from medicolegal practice. Over thirty varieties of potential skin simulants were shot perpendicularly, and at 45°, at a distance of 10 m and 0.3 m, using full metal jacket (FMJ) projectiles (9 × 19 mm Luger). Simulants included ballistic gelatine at various concentrations, dental silicones with several degrees of hardness, alginates, latex, chamois leather, suture trainers for medical training purposes and various material compound models. In addition to complying to the general requirements for a synthetic simulant, results obtained from dental silicones shore hardness 70 (backed with 20 % by mass gelatine), were especially highly comparable to gunshot entry wounds in skin from real cases. Based on these results, particularly focusing on the macroscopically detectable criteria, we can strongly recommend dental silicone shore hardness 70 as a skin simulant for wound ballistics examinations.
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Affiliation(s)
- Victoria K S Fischer
- Institute of Legal Medicine, Faculty of Medicine, University of Cologne, Melatenguertel 60/62, 50823, Cologne, Germany.
| | - Markus A Rothschild
- Institute of Legal Medicine, Faculty of Medicine, University of Cologne, Melatenguertel 60/62, 50823, Cologne, Germany
| | | | - Thomas Kamphausen
- Institute of Legal Medicine, Faculty of Medicine, University of Cologne, Melatenguertel 60/62, 50823, Cologne, Germany
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Chattrairat A, Kandare E, Aimmanee S, Tran P, Das R. Development and characterisation of hybrid composite skin simulants based on short polyethylene fibre and bioactive glass particle-reinforced silicone. J Mech Behav Biomed Mater 2022; 136:105424. [PMID: 36283299 DOI: 10.1016/j.jmbbm.2022.105424] [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] [Received: 07/14/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 11/30/2022]
Abstract
Silicone elastomers are widely recognised as artificial skins for medical prosthesis and cranial injury assessment. Since silicone is not an ideal skin simulant due to the lack of mechanical stiffness and a fibrous structure, the present study aimed to tailor the mechanical and structural characteristics of silicone by integrating biocompatible reinforcements (namely, short polyethylene fibres and bioglass particles) to develop suitable bio-integrative skin simulant candidates. The influences of short polyethylene fibres and bioglass particles in the selected platinum silicone on the mechanical properties of silicone-based composite skin simulants were investigated with various factors, including filler concentration, KMnO4 surface treatment of the polyethylene fibre, and particle size. A comprehensive assessment of the tensile, compressive, and hardness properties of the examined composites was conducted, and they were compared with the properties of human biological skin. The results exhibited that the elastic moduli and the hardness of all composites increased with the concentration of both reinforcements. While integrating only the bioglass particles had the advantage of an insignificant effect on the hardness change of the silicone matrix, the composite with polyethylene fibres possessed superior tensile elastic modulus and tensile strength compared to those of the bioglass reinforced composite. The composites with 5% untreated polyethylene fibres, KMnO4 surface-treated fibres, and bioglass reinforcements enhanced the tensile elastic moduli from the pure silicone up to 32%, 44%, and 22%, respectively. It reflected that the surface treatment of the fibres promotes better interfacial adhesion between the silicone matrix and the fibres. Moreover, the smaller bioglass particle had a greater mechanical contribution than the larger glass particle. Systematically characterised for the first time, the developed composite skin simulants demonstrated essential mechanical properties within the range of the human skin and constituted better skin alternatives than pure silicone for various biomedical applications.
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Affiliation(s)
- Akanae Chattrairat
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia.
| | - Everson Kandare
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
| | - Sontipee Aimmanee
- Advanced Materials and Structures Laboratory, Department of Mechanical Engineering, Faculty of Engineering, King Mongkut's University of Technology, Thonburi, Thailand
| | - Phuong Tran
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
| | - Raj Das
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
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Kerkhoff W, Visser M, Mattijssen EJAT, Hermsen R, Alberink IB. A combined cowhide/gelatine soft tissue simulant for ballistic studies. Forensic Sci Int 2022; 338:111392. [PMID: 35872541 DOI: 10.1016/j.forsciint.2022.111392] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 07/14/2022] [Accepted: 07/15/2022] [Indexed: 11/26/2022]
Abstract
The ballistic resistance of a combined soft tissue simulant was studied, consisting of gelatine as a simulant for human muscle tissue and tanned cowhide (leather) as a simulant for human skin. The simulant was manufactured by applying cowhide to liquid ballistic gelatine, as the gelatine solidified in its mould. Combining a skin and muscle tissue simulant in this adhered way opens the possibility to produce purpose-built proxies for human body parts in ballistic studies or for forensic shooting incident reconstructions. Ballistic resistance of adhered cowhide - (bonded) to solidifying ballistic gelatine - was compared to that of the same material applied on gelatine blocks in loose condition. Ballistic resistance of tanned cowhide was found to be more consistent in adhered condition. This enhanced consistency is a benefit, increasing reproducibility of results in ballistic studies. Additionally, two ways to assess ballistic resistance of a skin simulant were described and compared. Logistic regression, from a number of measured velocities and associated (non)perforations is recommended for testing ballistic resistance.
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Affiliation(s)
- W Kerkhoff
- Netherlands Forensic Institute (NFI), PO Box 24044, 2490 AA The Hague, the Netherlands.
| | - M Visser
- Amsterdam University of Applied Sciences (AUAS), Forensic Science Group, PO Box 1209, 1000 BE Amsterdam, the Netherlands
| | - E J A T Mattijssen
- Netherlands Forensic Institute (NFI), PO Box 24044, 2490 AA The Hague, the Netherlands
| | - R Hermsen
- Netherlands Forensic Institute (NFI), PO Box 24044, 2490 AA The Hague, the Netherlands
| | - I B Alberink
- Netherlands Forensic Institute (NFI), PO Box 24044, 2490 AA The Hague, the Netherlands
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Kerkhoff W, Bolck A, Alberink I, Mattijssen EJAT, Hermsen R, Riva F. Pistol bullet deflection through soft tissue simulants. Forensic Sci Int 2018; 289:270-276. [PMID: 29913362 DOI: 10.1016/j.forsciint.2018.05.052] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 05/24/2018] [Accepted: 05/29/2018] [Indexed: 10/14/2022]
Abstract
Trajectory deflections of pistol bullets from four different firearms, fired through soft tissue simulants under two different incidence and exit angles were studied. The data from this study can be used in reconstructions of shooting incidents where human soft tissues (not bones) were perforated with pistol bullets and assumptions must be made about bullet deflection in order to correctly reconstruct trajectories. The results demonstrate that deflection was influenced by the length of the "wound channel" through the simulants. In short, deflection was small to virtually absent with 5 and 10cm channel lengths. With channel lengths of 15, 20 and 25cm, there was a clear increase in deflection and/or a more erratic deflection behaviour with most shots. The data also suggest an influence of the angle of incidence and/or exit on both the direction and the magnitude of the deflection.
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Affiliation(s)
- W Kerkhoff
- Netherlands Forensic Institute (NFI), PO Box 24044, 2490 AA The Hague, The Netherlands.
| | - A Bolck
- Netherlands Forensic Institute (NFI), PO Box 24044, 2490 AA The Hague, The Netherlands
| | - I Alberink
- Netherlands Forensic Institute (NFI), PO Box 24044, 2490 AA The Hague, The Netherlands
| | - E J A T Mattijssen
- Netherlands Forensic Institute (NFI), PO Box 24044, 2490 AA The Hague, The Netherlands
| | - R Hermsen
- Netherlands Forensic Institute (NFI), PO Box 24044, 2490 AA The Hague, The Netherlands
| | - F Riva
- Institut für Rechtsmedizin (IRM) Bern, Bühlstrasse 20, 3012 Bern, Switzerland
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Falland-Cheung L, Pittar N, Tong D, Waddell JN. Investigation of dental materials as skin simulants for forensic skin/skull/brain model impact testing. Forensic Sci Med Pathol 2015; 11:552-7. [PMID: 26434652 DOI: 10.1007/s12024-015-9718-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE The purpose of this study was to measure the tear strength and hardness of four different dental silicones in comparison to that of porcine skin. METHODS Specimens were prepared (n = 20/group) according to ASTM D624-00, using three hydrophilic vinyl polysiloxane impression materials, one duplication silicone, and fresh porcine skin. A universal testing machine was used to strain each test specimen until complete rupture and calculate its tear strength (kNm(-1)). Failure analysis was then conducted using a stereoscopic zoom light microscope, as well as a scanning electron microscope (SEM). A shore A-type durometer was used to measure the hardness of all specimens. RESULTS The tear strength for the silicones ranged from 1.75 to 9.58 kNm(-1) and the pigskin from 3.65 to 56.40 kNm(-1). The mean shore hardness for the silicones ranged from 16.275 to 62.65DU and the pigskin had a mean shore hardness of 22.65DU, with p values <0.0125 (0.05/4). Failure analysis of the silicone materials showed the origin of failure being in the tension side of the specimens and typical failure patterns were observed. Examining the materials under a SEM revealed that materials with higher viscosity presented with a larger amount of filler particle content than silicones with low viscosity, with the duplication silicone having no filler content. CONCLUSION Dental silicones are a good alternative for skin in studies that require a skin simulant.
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Affiliation(s)
- Lisa Falland-Cheung
- Sir John Walsh Research Institute, University of Otago, 310 Great King Street, Dunedin, 9016, New Zealand.
| | - Nicholas Pittar
- Sir John Walsh Research Institute, University of Otago, 310 Great King Street, Dunedin, 9016, New Zealand
| | - Darryl Tong
- Sir John Walsh Research Institute, University of Otago, 310 Great King Street, Dunedin, 9016, New Zealand
| | - J Neil Waddell
- Sir John Walsh Research Institute, University of Otago, 310 Great King Street, Dunedin, 9016, New Zealand
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