Structural Research And Optimization Of Front Energy Absorbing Devices Of Automobile

The energy absorbing device in front of the car is the most important protective device for the frontal collision of the car,which plays an important role in improving the collision performance of the car and protecting the safety of the occupant.And the use of lightweight materials instead of traditional materials can improve the collision performance and lightweight effect of the car.In response to this problem,the bumper beam and energy-absorbing box at the front of the car are studied to improve the passive safety and lightweight design of the car.Firstly,the structural energy thickness prediction theory of equal energy absorption is applied to analyze the collision energy absorption characteristics of different energy-absorbing boxes,and the material and structure of the energy-absorbing box are improved.Then,the carbon fiber composite material is used to replace the original bumper beam according to the equivalent generation design theory.The material of the beam is simulated and compared with the optimization of the pavement.Finally,the multi-objective optimization of the bumper beam system composed of bumper beam and energy-absorbing box is carried out by the design of experiment method,then the optimization results are obtained and verified.The detailed research contents are as follows:(1)The basic principles of the structural design of automobile energy-absorbing boxes,the choice of materials for energy-absorbing boxes,and the evaluation indexes of the collision performance of energy-absorbing boxes were analyzed,which provided the basis for evaluating the collision performance of steel and aluminum energy-absorbing boxes.The collision analysis model of the energy-absorbing box is established,and the basic theory of the nonlinear finite element method and the explicit central difference method used by LS-DYNA for the collision problem are analyzed.According to the corresponding parameters,a three-dimensional model of the energy-absorbing box was established,and the meshing and material parameter settings,contact and constraint settings,working conditions and control card settings were performed.Among them,the contact problems of the simulation process,hourglass control,and the problem of time step control and mass scaling in LS-DYNA are analyzed in detail.(2)According to the prediction theory of the structure thickness of equal energy absorption,the relevant parameters of the aluminum energy-absorbing box were obtained,and the thickness of the aluminum energy-absorbing box was analyzed and verified.Then,the low-speed collision simulation analysis of the steel energy absorption box and the aluminum energy-absorbing box is performed,and it is concluded that the aluminum energy-absorbing box has a relatively balanced collision energy absorption performance and a good lightweight effect.Four kinds of aluminum energy-absorbing boxes with different internal structures are designed,and the comparison analysis shows that the collision performance of the aluminum mesh with a ‘mu' structure of the third scheme is the best among the four schemes,so the third scheme The structure of this solution serves as an improved aluminum energy absorption box structure.(3)According to the requirements of GB17354-1998 "Automobile front and rear protection devices",the low-speed collision simulation model of the bumper beam system is established.The bumper beam adopts the design theory of equal stiffness to replace the original high-strength steel material with carbon fiber composite material,because of the carbon fiber composite bumper beam has better energy absorption performance and lightweight effect.Then,the layered form of the carbon fiber composite bumper beam is optimized,and the collision performance of the carbon fiber bumper beam is improved.(4)The Hyper Study and LS-DYNA software were used to optimize the multi-objective optimization of the anti-collision beam system by using approximate modeling.The optimal Latin hypercube method was used to obtain 20 groups of sample points,and the Hyper Kriging approximate modeling method was used to construct the response surface model.The genetic algorithm was used to carry out optimization calculation and verify the optimization results.By comparing and analyzing the optimized collision beam system with the original collision beam system,the optimized collision beam system has better low-speed collision performance,and the weight reduction effect is obvious.This article explores the lightweight structure and structural optimization methods of front-end energy absorption devices for automobiles.The research results in this paper show that the optimized collision beam system not only has better low-speed collision performance than the original collision beam system,but also reduces weight by 58.9% based on the original collision beam system,which has certain reference significance and application value for improving the collision energy absorption performance and lightweight effect of the frontal energy-absorbing components.