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. © 2022 Explosion and Shock Waves. All rights reserved.