爆炸冲击波作用下人体肺部的损伤

为探究肺部爆炸伤的致伤机制与评价指标，构建了人体-爆炸流场有限元模型，通过与爆炸事故中人员损伤情况比对，验证了模型的有效性。共进行39个爆炸工况的数值模拟，通过改变爆炸当量与距离，使得胸部受到不同量级爆炸载荷作用，肺部损伤等级从无损伤到严重损伤。通过分析爆炸流场分布、胸腔动力学响应、肺部应力分布等阐明肺部爆炸伤的力学机制。基于人体有限元模型输出的损伤响应，提出肺部爆炸伤的评价指标。研究结果表明:在爆炸载荷作用下，胸前壁高速撞击胸腔脏器，导致肺部产生应力波。随后在惯性作用下，胸前壁持续挤压胸腔脏器，并造成胸腔变形。应力波是造成肺部损伤的主要原因，胸腔变形挤压肺部造成的损伤风险较低。肺部损伤集中在靠近胸前壁及心脏的区域。胸骨速度峰值和胸骨加速度峰值可作为肺部爆炸伤的评价指标。胸部压缩量及黏性响应系数不能反映应力波对肺部造成的损伤，不适合评价肺部爆炸伤。

Blast injuries to human lung induced by blast shock waves

In order to study the mechanism and the predictors of blast lung injuries, a finite element model including the human body and the explosion flow field was developed. The fluid-structure coupling algorithm of LS-DYNA was used to simulate the blast effect on the thorax. The developed model was validated using victims’ lung injury data in an explosion accident. A total of 39 simulation experiments were carried out. By changing the explosion equivalent and stand-off distance between the thorax and the explosive, the thorax was subjected to blast loads of different magnitudes, and the lung injuries ranged from no injury to extensive injuries. Base on the developed model, the pressure distribution in the explosion flow field, the dynamic response of the thorax and the stress distribution in the lung were investigated to clarify the mechanical mechanism of blast lung injuries. The thorax injuries and response of the human body model were analyzed, and the predictors of blast lung injuries were proposed. The results show that when subjected to the blast load, the anterior chest wall gains speed almost instantly and impacts the thoracic organs with a high velocity, causing the propagation of stress waves in the lung. Subsequently the anterior chest wall continuously compresses the thoracic organs and the ribs under inertia, which causes the thoracic deflection. The stress wave is the main cause of blast lung injuries, and the thoracic deflection is less likely to cause lung injuries. The damaged lung tissues are mainly in the area close to the anterior chest wall and heart. The peak sternum velocity and peak sternum acceleration have direct effects on the stress wave in the lung, and can be used as the predictors of blast lung injuries. The thoracic deflection and viscous criterion cannot reflect the damage to the lung caused by stress wave, and are not suitable for evaluating the blast lung injuries.