Impact and Armour Group, Department of Engineering and Applied Sciences, Cranfield University, Defence Academy of the United Kingdom, Shrivenham, Wiltshire SN6 8LA, UK.
Forensic Sci Int. 2011 Jul 15;210(1-3):42-6. doi: 10.1016/j.forsciint.2011.01.032. Epub 2011 Mar 2.
Forensic investigators commonly use simulants/backing materials to mount fabrics and/or garments on when recreating damage due to stab events. Such work may be conducted in support of an investigation to connect a particular knife to a stabbing event by comparing the severance morphology obtained in the laboratory to that observed in the incident. There does not appear to have been a comparison of the effect of simulant type on the morphology of severances in fabrics and simulants, nor on the variability of simulants. This work investigates three simulants (pork, gelatine, expanded polystyrene), two knife blades (carving, bread), and how severances in the simulants and an apparel fabric typically used to manufacture T-shirts (single jersey) were affected by (i) simulant type and (ii) blade type. Severances were formed using a laboratory impact apparatus to ensure a consistent impact velocity and hence impact energy independently of the other variables. The impact velocity was chosen so that the force measured was similar to that measured in human performance trials. Force-time and energy-time curves were analysed and severance morphology (y, z directions) investigated. Simulant type and knife type significantly affected the critical forensic measurements of severance length (y direction) in the fabric and 'skin' (Tuftane). The use of EPS resulted in the lowest variability in data, further the severances recorded in both the fabric and Tuftane more accurately reflected the dimensions of the impacting knives.
法医调查人员通常使用模拟物/衬垫材料来固定织物和/或衣物，以便在重现刺伤事件造成的损伤时使用。这种工作可能是为了支持一项调查而进行的，通过将实验室中获得的切断形态与事件中观察到的形态进行比较，从而将特定的刀与刺伤事件联系起来。似乎没有人比较过模拟物类型对织物和模拟物中切断形态的影响，也没有人比较过模拟物的可变性。这项工作研究了三种模拟物（猪肉、明胶、膨胀聚苯乙烯）、两种刀片（雕刻刀、面包刀），以及模拟物和通常用于制造 T 恤的服装面料（单卫衣）中的切断是如何受到（i）模拟物类型和（ii）刀片类型的影响的。使用实验室冲击装置形成切断，以确保在不考虑其他变量的情况下保持一致的冲击速度，从而保持一致的冲击能量。选择冲击速度是为了使测量的力与人体性能试验中测量的力相似。分析了力-时间和能量-时间曲线，并研究了切断形态（y、z 方向）。模拟物类型和刀片类型显著影响了织物和“皮肤”（Tuftane）中切断长度（y 方向）的关键法医测量值。使用 EPS 可最大程度地减少数据的可变性，此外，在织物和 Tuftane 中记录的切断更准确地反映了冲击刀具的尺寸。
