非致命动能弹钝性冲击假人胸部的数值模拟

为验证应用Hybrid III假人开展非致命动能弹钝性冲击损伤的有效性,揭示动能弹钝性冲击与汽车安全领域大质量低速冲击的不同,采用数值模拟的方法研究了非致命动能弹和大质量冲击物钝性冲击Hybrid III 50^th假人胸部的动态过程,并基于粘性标准对非致命动能弹胸部损伤风险进行了数值评估。结果表明:Hybrid III假人在非致命动能弹钝性冲击下的胸部压缩量和粘性指数最大值均在尸体实验的验证区间内,是一种有效的损伤评估替代物; 在同等初始能量下,非致命动能弹钝性冲击时程更短、冲击力峰值更大、能量衰减速度更快,会造成胸部局部动能和内能的快速转换,从而形成局部表面伤,创伤面大于弹体横截面,且在肋骨前侧拐角处首先出现应力集中,容易造成断裂; 而大质量低速冲击时的冲击物动能大部分转化为胸部内能,损伤伤情以胸内骨折和脏器损伤为主。质量为30 g的L5型棍弹速度超过74.6 m/s时,造成胸骨或两根以上肋骨骨折的概率超过50%。

Numerical Simulation of Non-lethal Kinetic ProjectilesBlunt Impact on Dummy Chest

To verify the effectiveness of applying hybrid III dummy to assess blunt impact injury of non-lethal kinetic projectiles(NLKPs)and reveal the difference between blunt impact of NLKPs and high-mass low-speed impact in the field of vehicle safety,the dynamic process of NLKPs and high-mass impactor impacting on Hybrid III 50^th dummy were analyzed by numerical simulation method. The risk of chest injury was evaluated numerically based on viscous criterion. The results show that the chest compression and the max of viscous criterion of hybrid III dummy under the blunt impact of NLKPs are within the validation corridors of Post Mortem Human Subjects(PMHS)experiments,which indicates that the simulation method is an effective substitute for injury assessment. Under the same initial kinetic energy,the impact process of NLKPs would be shorter,the peak impact force would be higher and the energy attenuation would be faster. There would be rapid conversion of the kinetic energy and the internal energy in part of the thorax under NLKPs impact which causes superficial injuries and the wound surface is larger than the cross-section area of the projectile. The stress which is first concentrated at the front corner of ribs which would cause fracture. By contrast,most of the kinetic energy of high-mass impactor is converted to the internal energy of the thorax resulting injury types are mainly intra-thoracic fracture and internal organs injuries. When the velocity of the L5 projectile at 30 g exceeds 74.6 m/s,the probability of observing 2 or more rib fractures or a sternum fracture would exceed 50%.