Ballistic limits of tissue and clothing.
Annals of the New York Academy of Sciences (Impact Factor: 4.31). 11/1968; 152(1):163-7. DOI: 10.1111/j.1749-6632.1968.tb11973.x
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ABSTRACT: Explosively propelled fragments are the most common cause of injury to soldiers on current operations. Researchers desire models to predict their injurious effects so as to refine methods of potential protection. Well validated physical and numerical models based on the penetration of standardised fragment simulating projectiles (FSPs) through muscle exist but not for skin, thereby reducing the utility of such models. A systematic review of the literature was undertaken using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses methodology to identify all open source information quantifying the effects of postmortem human subject (PMHS) and animal skin on the retardation of metallic projectiles. Projectile sectional density (mass over presented cross-sectional area) was compared with the velocity required for skin perforation or penetration, with regard to skin origin (animal vs PMHS), projectile shape (sphere vs cylinder) and skin backing (isolated skin vs that backed by muscle). 17 original experimental studies were identified, predominantly using skin from the thigh. No statistical difference in the velocity required for skin perforation with regard to skin origin or projectile shape was found. A greater velocity was required to perforate intact skin on a whole limb than isolated skin alone (p<0.05). An empirical relationship describing the velocity required to perforate skin by metallic FSPs of a range of sectional densities was generated. Skin has a significant effect on the retardation of FSPs, necessitating its incorporation in future injury models. Perforation algorithms based on animal and PMHS skin can be used interchangeably as well as spheres and cylinders of matching sectional density. Future numerical simulations for skin perforation must match the velocity for penetration and also require experimental determination of mechanical skin properties, such as tensile strength, strain and elasticity at high strain rates.Journal of the Royal Army Medical Corps 06/2013; · 0.81 Impact Factor
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ABSTRACT: Ballistic gelatin is well validated in its ability to simulate the retardation of bullets into homogenous muscle. However the relationship is less clear for fragmentation projectiles and non-homogenous tissues as would truly be found in a human. 0.16 g, 1.10 g and 2.84 g NATO standardised cylindrical Fragment Simulating Projectiles (FSPs) were fired at a range of velocities (112-1652 m s(-1)) into four body areas (thigh, abdomen, thorax or neck) of six pig cadavers as well as 20% gelatin. Cadavers were imaged by Computed Tomography (CT) scanning and FSP Depth of Penetration (DoP) ascertained through radiology followed by dissection by a forensic pathologist. 106/149 (71%) FSPs were retained in tissues enabling DoP measurements and 43/149 (29%) exited the subjects. There was significantly less retardation of FSPs in the thorax and abdomen compared to gelatin but no difference in retardation in leg and neck tissue compared to gelatin. Although the gradient appeared identical for the 2.84 g FSP as well, there were insufficient FSPs retained in the neck and leg for meaningful analysis to be undertaken. Porcine leg and neck muscle was demonstrated to be comparable to 20% ballistic gelatin in terms of retardation, validating the use of projectile penetration algorithms derived from this tissue simulant. The effect of pig skin was significant for the 0.16 g FSP, especially at lower velocities, and we would therefore suggest that specific algorithms for any future numerical injury models be based directly from animal data or validated skin simulants for this smaller sized FSP. Reproducing the retardation effects of FSPs in the thorax and abdomen using tissue simulants alone will be problematic due to the anatomical complexity as well as multiple tissue-air interfaces and we would recommend further research in this area.Journal of Forensic and Legal Medicine 05/2013; 20(4):296-9. · 0.99 Impact Factor
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ABSTRACT: The fluting of Folsom points is an elegant technological solution to several problems faced by highly mobile hunters focused on bison procurement. The symmetrical, bifluted form allowed a split, facial-contact haft to extend nearly to the tip, thereby controlling both location and extent of fracture and allowing many cycles of point reworking. Extreme thinness achieved by fluting facilitated leading edge sharpness for enhanced penetration. The near-constant cross- section from tip to base meant no loss of leading edge acuteness upon resharpening and inter-changeability of broken segments. The high-friction, forwardly adjustable haft assured firm mounting even with shortened, reused point segments. This efficient design was critical for groups who spent weeks and maybe months away from raw material sources in pursuit of game. Short, exhausted Folsom points or “slugs” are what archaeologists most commonly find and study. In contrast, a quite long, fully fluted point made from a yet longer preform was the intended product of the Folsom knapper. The model presented here can be tested through study of preform length, finished point proportions, fracture patterns, haft element features, and use-wear analysis in archaeological specimens, as well as actualistic hunting experiments. The engine driving persistent use of snap blade, full fluted projectile technology was focused commitment to a single, highly mobile game species (bison). This specific technofunctional element in Folsom culture reveals a weapon system designed to mitigate against extreme risk regarding access to raw material. Continuing research should demonstrate that the appearance, geographic distribution, persistence, and disappearance of the Folsom fluted point relate closely to juxtapositions of climatic change, biotic change, and human population movements that occurred near the end of the Pleistocene.Journal of Archaeological Science - J ARCHAEOL SCI. 01/2000; 27(9):799-820.
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