Analysis And Optimization For Collision Safety Performance Of A Vehicle

Vehicle collision safety performance concerns the safety and security of every occupant.In the face of an increasingly severe road traffic environment,when a vehicle accident occurs and the collision is inevitable,good collisionworthiness is the last line of defense for the safety of occupants.Therefore,research on the collision safety performance of vehicles is always an important part of the vehicle R&D process.Based on the summarization of vehicle collision safety technology both at home and abroad,this paper takes the body of a domestic car as the research object,adopts the method of multiobjective optimization and structural optimization,and conducts the optimization research on the vehicle body collision safety.The main research content of this paper is as follows:(1)Body finite element modeling and collision simulation analysis.Based on the finite element collision simulation theory,Hypermesh software was used to carry out the geometrical cleaning,meshing,material property setting and control parameter setting of a car body CAD model,and a body finite element model was established.The LS-DYNA solver was used to simulate the 100% rigid wall collision at the front of the vehicle at a speed of 50 km/h.The validity of the finite element model was verified.The deformation of key parts,the deformation of the key parts,the collision force of the front end of the vehicle,and the speed of the B-pillar were used for the vehicle body deformation.Acceleration response,front panel intrusion,and body modal frequency were analyzed as the basis for vehicle body collision safety optimization.(2)Multi-objective optimization of vehicle collision safety based on 6? reliability criterion.Nine key component thicknesses at the front of the car body are selected as the collision safety optimization design variables;the weight and first-order torsional modal frequencies of the car body are taken into consideration in consideration of the requirements for lightweight and comfort of the vehicle;and the root mean square of the rigid wall reaction force is selected.The energy-absorption ratio,front wall intrusion amount,and peak acceleration of B-pillar are the optimization goals.In order to reduce the impact of design-variation disturbances on the optimization results,6? reliability design criteria are used to establish a multi-objective reliability optimization model for vehicle body collision safety.An optimal Latin hypercube experimental design method was used,combined with an RBF radial basis neural network to build an approximate model,and a non-dominated sorting genetic algorithm(NSGA-II)was used to optimize the collision safety of the vehicle body.After optimization,the collision safety performance of the vehicle body has been improved,and the quality level of the optimized solution also meets the reliability requirements.(3)Optimization of front longitudinal beam structure for collision safety.The simplified finite element model of the front longitudinal beam is used to optimize the front end of the front longitudinal beam with small deformation and large stiffness requirements.For the middle section of the front longitudinal beam with large displacement and incomplete collapse during the collision,the pre-deformation is adopted.The method of opening the induction tank.After finite element simulation and verification,after the optimization of the front sidemember structure,the safety performance of the vehicle body collision has been further improved compared with the original optimization scheme of the thickness of key parts.Compared with the finite element collision simulation results of the initial state of the car body,the final optimization solution does not change,the first-order torsional modal frequency of the car body increases by 0.56%,and the root wall of the rigid wall collision reaction force decreases by 10.8%.The energy ratio increased by 3.7%,the amount of front wallboard intrusion was reduced by 5.8%,the acceleration of B-pillar was reduced by 18.2%,and the optimized scheme significantly improved the collision safety performance of the vehicle.