China Institute of Sport Science
National Key R&D Program of China (2017YFC0803802)
目的 刀器砍击案件中，上肢是人体最主要的主动防御部位。本文旨在定量探究刀器锋利程度对前臂损伤的影响。方法 以人体CT图像和砍刀原型为基础，建立锐利、钝口和宽口3种锋利程度的刀器和上臂有限元模型，分别仿真刀器以4 m/s的速度、0.01 s的持续时间砍击前臂的过程，分析接触力、砍创尺寸和能量的变化。结果 锐利、钝口和宽口刀器在砍击过程中分别于65 ms、85 ms和95 ms接触尺骨，砍击力峰值分别为846 N、1064 N和1865 N，砍创长度为135.64 mm、105.47 mm和99.23 mm，深度为38.77 mm、27.81 mm和18.74 mm。与钝口和宽口刀器相比，锐利刀器砍击时模型系统总能量明显较大，内能也较高，但所产生的系统动能却较小。结论 本文建立了定量评估刀器砍击上臂创口形成过程的方法。随着刀器锋利程度降低，创口形成速度减慢、长度和深度减小，砍击力增加。
Objective The upper arms are main defensive parts in knife slash injuries. This work was to explore the effluence of knife sharpness on forearm wounds in slash injuries in quantity. Methods Finite element models of an upper arm and knifes with 3 sharpness (A, B, and C, from the sharpest to bluntest) were developed based on human CT images and a prototype of a slash knife. Computer simulations were performed to analyze contact forces, wound dimensions and energy changes during slashing with velocity of 4 m/s and 0.01 s duration on the forearm using the 3 kinds of knife. Results The blades reached the ulna at about 65 ms, 85 ms, and 95 ms for A, B and C respectively. Moreover this, the corresponding slash forces were 846 N, 1064 N, and 1865 N; the wound lengths were 135.64 mm, 105.47 mm and 99.23 mm; and the wound depths were 38.77 mm, 27.81 mm, and 18.74 mm. Compared to B or C, the total energy and inner energy of the model system for A were obviously greater, but kinetic energy for A was less. Conclusions A novel method based on finite element analysis has been developed for quantitatively assessing wounds formation in knife slash upon upper arms. The wound formation is slowed, depth decreased and slash force increased while the knife is blunted.