Research On Driver Head, Chest And Lower Extremity Injuries In The Car Frontal Impact

Road traffic accidents, which seriously threaten the Socio-economic development and people’s lives and properties, have become a great public harm in the world. In recent years, the incidence of frontal impact accidents is rising, and occupies nearly one-third of traffic fatalities. Studies have shown that the head, the chest and the lower extremity are the main injury parts of the driver in frontal impacts. Head and chest injuries are the primary causes of serious injury or even death. Lower extremity injuries have historically been ignored due to their non-lethal nature, but the significance of lower extremity injuries lies not only in their frequency but also in their high cost of treatment and likelihood to lead to long-term disability and impairment. Currently, the finite element models have been used to study the human head, chest and lower extremity injuries abroad for several years, but domestic researches in this area are still rare.The aim of this thesis is to identify the relationship between the main dangerous source and the head, chest and lower extremity injuries by using FEM (Finite Element Method). Moreover, the protection for drivers is promoted by parameters optimization research on restraint systems.The finite element model for driver injury analysis was comprised of three parts: the vehicle body model, the restraint system model and the dummy model. The vehicle body model and the restraint system model were built by using Hypermesh software, and Hybrid Ⅲ50th dummy model was validated as the evaluated object. The results show that the model for driver injury analysis was in good accordance with the real test data. Consequently, kinematics responses and features of the main injuries were studied by using driver injury analysis model. In addition, influencing parameters, which include the restraint system, the cabin environment and the driver status, are selected as the independent variables to analyze their influence to driver head, chest and lower extremity injuries counterbalanced by the orthogonal experiment design method, and a systematic method for analysis of drive injuries was carried out by drawing the trend picture and differential analysis. Finally, based on the study mentioned above, the minimal WIC (Weighted Injury Criterion) value was taken as the optimization object, by the response surface analysis of the restraint system with genetic algorithm. Simulation results indicate that the vent hole size, the gas generator mass flow rate, the load value of force-limiter and the friction coefficient of D ring exert dominant influences on the driver’s head and chest injury, and the most important influence factors for lower extremity injuries are the footwell intrusion and the lower extremity posture. After restraint system parameters optimization, the WIC value has been dropped from0.42to0.37with the decrease rate of11.9%,and the protection performance of the restraint system has been improved.