高速投射物对软防护下人体胸廓靶标钝击机理研究

The high-speed projectile impacts but does not perforate the body armor, will still produce blunt trauma to the human body behind body armor. At present, the quantitative relationship between the blunt trauma effect and the projectile factors are not fully clear, the injury mechanism of blunt trauma remains to be elucidated. This project intends to adopt the dynamic mechanical experiment, ballistic impact experiment and numerical simulation to study the blunt trauma mechanism between the high-speed projectile and soft armor covered thoracic cage target. The dynamic material parameters of UHMWPE unidirectional sheet and ballistic gelatin will be measured using split Hopkinson bar apparatus, and their dynamic constitutive model will be set up respectively. The multi-parameter synchronous measurement technology will be adopted to study the quantitative influence law of the projectile impact velocity, angle of incidence and geometry shape on blunt trauma effect. Then, the blunt trauma numerical model of human thoracic cage will be constructed and computed using open-source computational biomechanical software FEBio, and comparison with the experimental results to verify and improve the numerical model. Based on experimental and numerical results, the energy transfer law, contours of stress and strain in target, and bone indirect damage mechanism are analyzed in depth. This study not only can provide scientific basis for improving killing power and effectiveness evaluation of small arms, but also provide references for body armor optimization and blunt trauma prevention.

高速投射物击中而未穿透防弹衣的情况下，仍会对防弹衣后的人体产生钝击伤害。目前对钝击过程中各种物理现象与投射物物理因素之间的定量关系尚未完全明晰，钝击效应的致伤机理还有待进一步阐明。本项目拟采用材料动态力学实验、弹道冲击实验和数值计算相结合的方法研究高速投射物对软防护下人体胸廓靶标的钝击机理。采用霍普金森杆装置测量UHMWPE无纬布和弹道明胶动态力学特性，并分别构建其动态本构模型；采用多参数同步测量技术对投射物撞击速度、入射角度和几何形状等对钝击效应的定量影响规律进行实验研究；建立人体胸廓靶标钝击效应数值计算模型并在开源计算生物力学软件FEBio中进行求解，通过与实验结果对比来验证和完善数值模型。深入分析撞击过程中的能量传递规律、靶标内应力场、应变场随时间空间变化规律及骨骼间接损伤机制。该研究不但可以为轻武器杀伤威力提高和杀伤效能评估提供科学依据，而且也将为防弹衣改进及钝性损伤预防提供参考。

本项目拟采用材料动态力学实验、弹道冲击实验和数值计算相结合的方法研究高速投射物对软防护下人体胸廓靶标的钝击机理。采用霍普金森杆装置测量了UHMWPE复合材料的动态力学特性，研究了试件形状对测量结果的影响规律。采用万能材料试验机和霍普金森杆分别测量了弹道明胶的准静态和动态力学特性，试验结果表明，弹道明胶在低应变率和高应变率的范围内有着明显的应变率效应。基于试验数据，建立了含应变率本构模型，并给出了20%弹道明胶的材料常数。建立了“明胶-胸廓”仿生人体躯干，进而搭建了同步测试系统开展手枪弹侵彻有防护人体靶标的试验研究。将压力传感器埋设在心脏和左肺部位，获得了人体典型位置受到枪弹钝击时这两个部位的动态压力特性。高速摄影拍摄到的侵彻过程表明，软质防弹衣会产生非常大的瞬态凹陷，随后在人体靶标弹性能的作用下凹陷深度和范围又逐渐减小。进行了手枪弹侵彻软防护下人体上躯干靶标的数值模拟，计算获得的软质防弹衣和弹丸的受损情况与实弹试验中的受损情况基本保持一致。计算结果表明，侵彻初期防弹衣以剪切破坏为主，对子弹的阻挡作用较差，子弹能量损耗较小，速度缓慢下降。随着子弹的镦粗变形，防弹衣后部无纬布主要发生拉伸变形，从而有效的吸收了子弹的撞击动能，子弹速度急剧下降。弹着点为心脏部位时，左肺最大等效应力为0.231MPa，右肺有限元模型的最大等效应力为0.363MPa，心脏最大等效应力为0.056MPa。该研究不但可以为轻武器杀伤威力提高和杀伤效能评估提供科学依据，而且也将为防弹衣改进及钝性损伤预防提供参考。