The Influence of Knife Sharpness on Forearm Wounds in Knife Slash Cases
10.16156/j.1004-7220.2020.05.05
- VernacularTitle:砍击案件中刀器锋利程度对前臂损伤的影响
- Author:
Weiya HAO
1
;
Songjunjie SHAN
1
,
2
;
Yi SHI
3
;
Chaopeng YANG
3
;
Chengliang WU
1
;
Wei HE
1
;
Zhenfang XIN
4
;
Jian WANG
3
;
Mingzhi WANG
3
Author Information
1. China Institute of Sport Science, General Administration of Sport of China
2. College of Science, China Agricultural University
3. Institute of Forensic Science, Ministry of Public Security,
4. Beijing Institute of Machinery and Equipmen
- Publication Type:Journal Article
- Keywords:
sharp injury;
upper limb;
forensic biomechanics;
finite element method
- From:
Journal of Medical Biomechanics
2020;35(5):E546-E552
- CountryChina
- Language:Chinese
-
Abstract:
Objective To quantitatively explore the influence of knife sharpness on forearm wounds in knife slash cases. Methods The finite element models of the upper limb and knives with 3 degrees of sharpness (with sharp blade, blunt blade, wide blade) were developed based on human CT images and prototype of slash knife. The slash by 3 kinds of knives on the forearm at velocity of 4 m/s and duration of 10 ms was simulated, so as to analyze changes in contact forces, wound dimensions and energy. Results During the slash by knives with sharp, blunt, wide blade, the blades reached the ulna at about 65, 85, 95 ms, respectively. The corresponding slash forces were 846, 1 064 and 1 865 N; the wound lengths were 135.64, 105.47 and 99.23 mm; the wound depths were 38.77, 27.81 and 18.74 mm. With the sharpness of blade decreasing, the wound formation was slowed, the length and depth decreased and the slash force increased. The model system for slash knife with sharp blade had obviously greater total energy and inner energy, but smaller kinetic energy, compared with slash knife with blunt blade and wide blade. Conclusions The method for quantitatively assessing wound formation in knife slash upon the forearm was developed. The research findings deepen the understanding of biomechanical mechanism of wound formation by knife slash, and provide new scientific means for forensic investigation and court trial of knife slash cases.
