A study on pedestrian thorax impact responses and deflection measurement methods using the THUMS human model

During vehicle-pedestrian impact accidents, thorax injury is the second most fatal injury after head injury, and it is very important to conduct research on the mechanism and protection of pedestrian thorax injury. In this paper, the impact simulation models between vehicle model and THUMS pedestrian human body model were established. Chestbands were set in the human body model and four different methods were applied to measure chest compression. The thorax deflection and rib strain were studied during collisions with vehicles of different hood heights and hood angle, and correlation analysis was conducted between thorax deflection and rib strain. The results of different thorax deflection measurement methods was compared. The results indicate that there are significant differences in deformation and injury risk of the pedestrian thorax during collisions between vehicles with different hood heights and hood angle. For sedans, the risk of upper chest injury is higher; for SUVs, the risk of lower chest injury is higher. As the hood angle increases, chest injury also increases. The thorax deflection measurement methods 2–4 show a significant correlation between deflection and rib strain, which can better reflect the risk of chest injury.