| With the rapid development of automobile industry in our country,the car ownership in our country increases year by year.At the same time,it also leads to the increase of traffic accident rate to a certain extent,arousing people’s growing concerns about traffic safety.In the car crash,pedestrians were particularly vulnerable as the weaker side,with injuries to the head being another major cause of pedestrian death.The car is the most common car accident models,the front structure is the most direct cause of pedestrian head injury.Therefore,it is of great significance to study and optimize the pedestrian head protection performance of the car front-end structure.Firstly,this paper deeply analyzes the current research status and research methods of pedestrian protection technologies at home and abroad,studies the main characteristics of current human-vehicle collision accidents,and summarizes and analyzes related theories of head injury biomechanics for follow-up.The study provided important theoretical support and made a good preparation.Subsequently,according to the model of a production car,the front-end finite element model of the car was established by Hypermesh software.According to the Pedestrian protection regulations such as EEVC and the requirements of the component test prescribed by ACEA,the pedestrian head impactor finite element model was established.Based on this,the creation and validation of the finite element model of pedestrian-car front-end collision were completed.After verification,the established head-collision model complies with regulatory requirements and can restore the collision process more realistically.Therefore,it can be used as a virtual platform for research on pedestrian head protection.After the completion of the model creation,the finite element analysis method is used to study the head safety problem in the pedestrian-car collision accident.Firstly,according to the Euro NCAP v8.2 test protocol,PreSys software was used to divide the pedestrian head crash test area of the car front end model.Then select 10 test points that reflect the head protection performance in all directions in the divided test area,and use LS-DYNA software to perform single-point position collision analysis.According to the simulation results of each test point and considering the structural arrangement of the vehicle body,the pedestrian head protection performance of the original vehicle is studied,and theimprovement idea for the local crash safety performance is proposed.After further analysis,the structural parameters that mainly affect the head injury of pedestrian are determined as the focus of subsequent optimization.The thickness of the engine cover,the inner cover thickness,the thickness of the hood hinge and the thickness of the hinge stiffener are determined.According to the orthogonal test design method to design the test plan,and orthogonal experiments were used to obtain the significance of the structural parameters of pedestrians’ head injuries.Based on this,a comprehensive analysis was performed to determine the optimal optimization scheme for each structural parameter.Finally,the proposed optimization scheme is verified.The results show that the optimized front structure of the car can significantly reduce the damage caused to the head of the pedestrian,and the pedestrian head protection performance of the car is improved,so the optimization solution of the car front-end structure based on pedestrian head protection is reasonable and effective. |
