Safety Performance Analysis And Lightweight Design Of Vehicle Front Bumper Beam System

Vehicle front bumper beam system is the first line of defense to protect the safety of the vehicle occupants.In the event of a collision,the vehicle front bumper beam system can effectively absorb the collision energy and reduce the damage to the important components of the vehicle front-end and the injury of the vehicle occupants.On the other hand,with the increasingly serious environmental pollution and the gradual consumption of non-renewable energy,to save energy and reduce emissions,vehicle lightweight design has become the focus of attention.Vehicle front bumper beam system is an important part of vehicle body,and its lightweight design can effectively reduce the mass of body.In vehicle design,lightweight and safety performance is a pair of contradictions,how to take into account the safety performance and lightweight effect has become a major difficulty in current research.It is a feasible way to analyze the safety performance of the vehicle front bumper beam system in multiple working conditions and optimize the structural parameters,which can provide reference for the design of the vehicle front bumper beam system.The main research work of this thesis mainly includes the following aspects:Bending strength and low-speed collision performance analysis.This thesis takes the vehicle front bumper beam system of a certain car as the research object,establishes its three-point bending finite element model,and uses the vehicle front bumper beam system as a reference to establish another three-point bending finite element model of the vehicle front bumper beam system with roughly the same mass,and carries out simulation analysis.The analysis results show that the two types of vehicle front bumper beam system meet the design requirements of bending strength,but the performance is different.The vehicle front bumper beam system with better bending strength was selected for further study.The finite element model of low-speed collision of the vehicle front bumper beam system was established,and the effectiveness of the model was verified by the drop hammer impact test.Based on the vehicle low-speed collision regulations and the vehicle front-end accident rate,the vehicle front bumper beam system was calculated and analyzed in three different collision conditions,including front,angle,offset.The results showed that the vehicle front bumper beam system meets the design requirements of lowspeed collision and had a large lightweight design space.Influence of structural parameters on collision performance.The influence of the cross-sectional form,thickness and length of the energy absorbing box and beam on the impact performance and lightweight effect was discussed respectively under the frontal collision condition,and the best matching form between the energy absorbing box and beam was determined,which was a foundation for the selection of lightweight design variables in the following thesis.Vehicle front bumper beam system lightweight design.Taking vehicle front bumper beam system as the object of optimization,the probability of the three low-speed collision conditions occurring in the actual collision was taken as the weight of the performance index of each low-speed collision condition,and the collision performance index was weighted into a single quantity.Combined with radial basis neural network model,kriging model,response surface model and other proxy models,the optimization mathematical model was established.NSGA-Ⅱ optimization algorithm was used to search for optimization.Finally,under the premise of ensuring the safety performance,the weight of vehicle front bumper beam system was reduced by 12.24%,which has a good lightweight effect.