A Study On The Effect Of Pedestrian Lower Limb Muscle Initiative On Injury In Front Crash

With the development of national economy,the number of cars in our country has increased year by year.The number of road safety accidents ha s increased with the increase of the number of vehicles.In many road safety accidents,the number of pedestrian casualties accounts for a large and high proportion.Pedestrian safety has become an urgent social problem in road traffic safety.In the proce ss of vehiclepedestrian collision,lower limbs are the most vulnerable part of pedestrians and the main cause of disability.Therefore,it is of great practical significance to explore Pedestrian Lower Limb safety to reduce pedestrian lower limb injury in road traffic accidents.In this paper,the effects of pedestrian lower limb muscle initiative on the dynamic response and biomechanical response of lower limb injury during vehicle-pedestrian collision are studied.In order to achieve the research purpose,based on the finite element model of lower limbs of Hunan University,this paper uses Hypermesh software to improve the model.The main contents of the improvement are: adding the beam element which can simulate the active muscle force,and replacing the material parameters of the model according to the latest Biomechanical Experimental results.The improved finite element model of lower limb was validated by traditional biomechanical experiments.Finally,the improved lower limb finite element model and Hybrid III 50 percentile dummy finite element model(standing posture)are c oupled to establish a hybrid dummy model with active muscle force,and the coupling dummy model is validated.The results show that the hybrid dummy model has good bio-fidelity and can help to further study pedestrian lower limb injury.In the research process,the Camry vehicle model is used to assemble the test vehicle and the established hybrid dummy model to complete the simulation environment.According to the experimental purpose,the experimental scheme is set up to study the impact of different collision intensity and different muscle activation states on the dynamic response and biomechanical response of lower limb injury during the collision between vehicle and pedestrian.The results show that the dynamic and biomechanical responses of the lower limbs are affected by the impact strength and muscle activation during the vehicle-pedestrian collision.In terms of dynamic response,the femoral axial force and tibia l index of the lower limbs increase with the increase of impact strength.In addition,the femoral axial force and tibial index of the muscle in the active state are higher than the corresponding value of the muscle in the inactive state.In terms of biomechanical resp onse,the stress extremum of the main skeletons of lower limbs increases with the increase of collision strength,but when the muscles are activated,the maximum stress of the skeletons of lower limbs is lower than the maximum stress of the muscles in the inactive state.The muscle initiative reduces the stress value of the lower limbs to a certain extent and alleviates the lower limbs injury.It can be seen that the active muscle force has an impact on the dynamic response and biomechanical response of low er limb injury.