关键词: 间隙量, 防护性能, 虚拟试衣, 应变能, 有限元分析, 防弹衣

Abstract:

Objective Although body armor can block bullet penetration, the wearer can still suffer severe blunt trauma (BATA). There are gaps between the human body and the body armor, which may significantly affect the protective performance of the body armor and reduce the injury to the wearer. This study aims to investigate the impact of gap size on the protective performance of body armor using finite element analysis. This research is crucial for optimizing body armor design, enhancing wearer safety, and providing insights for future developments in protective clothing.

Method This study obtained human upper torso data through 3-D human body scanning to construct a geometric model of the human chest, ribcage, and external soft tissues. Virtual fitting software was used to accurately design body armor, build multi-layer body armor models of different sizes, perform accuracy analysis on the model, and verify the model's accuracy. Finite element analysis was performed using Abaqus/Explicit software. The mesh density at the impact location was adjusted, and impact simulation was performed according to the NIJ 0101.06 standard.

Results Finite element simulations showed significant differences in protective performance of body armor with different gap sizes. From the perspective of human body deformation, with the chest gap increased from 0 mm to 2.3 mm, the width and depth of human body deformation was decreasd by 1.27 times and 1.25 times, respectively, significantly reducing human body deformation. This change was more evident at the waist. Specifically, when the gap at the waist impact increased from 0 mm to 7.1 mm, the width and depth of the human body deformation were decreased by 2.06 times and 3.14 times, respectively. The human body deformation results show that increasing the gap size reduced the degree of human body deformation and the risk of blunt injury. The energy absorption capacity of the body armor and the human body's impact response time showd that when the gap at the chest impact area increases from 0 mm to 2.3 mm, the maximum strain energy absorbed by the body armor was increased by 1.51 times, the human body's impact response time was extended by 6 μs, and the kinetic energy of the bullet at the moment of contact was reduced by 24.3%. When the gap at the waist impact point increased from 0 mm to 7.1 mm, the maximum strain energy absorption of the body armor was increased by 2.69 times, the human body's response time was extended by 29 μs, and the bullet's kinetic energy at the moment of contact was reduced by 78.4%. These results indicate that increasing the gap size could significantly improve the protective performance of body armor and reduce the risk of human injury.

Conclusion The research results show that the air gap between the human body and the body armor provides additional buffer space, allowing the body armor to have more space and time to absorb energy when faced with bullet impact. The bulletproof material can absorb and disperse the impact force more effectively, greatly improving the protective effect of the body armor and reducing the kinetic energy transferred to the human body, thereby reducing the risk of blunt injury. Therefore, the larger the gap, the higher the strain energy absorbed by the body armor, the longer the peak occurs, and the smaller the damage to the human body. It is recommended to consider adding appropriate gaps in the design of body armor to improve practical protection effects. This study also provides a better perspective and scientific basis for designing other protective equipment. Further studies could explore varied materials and real-world testing to validate simulation results and refine protective clothing design.

Key words: air gap, protective performance, virtual fitting, strain energy, finite element analysis, body armor