Simulation Analysis And Optimization Design Of The Stretching-Bending Forming Of The Front Anti-collision Beam For Automobiles

Aluminum alloy materials have been widely used in the field of automotive lightweight because of their low density,excellent mechanical properties and impact properties.The front anti-collision beam of the automobile is the main energy absorbing structure in the collision of the automobile.The forming method is the bending and forming,and the dimensional accuracy and molding quality directly affect the collision performance of the anti-collision beam.Different from the traditional steel anticollision beam,the aluminum alloy anti-collision beam is prone to forming defects such as wrinkling,cracking and cross-section distortion,which affects the forming quality of the aluminum alloy anti-collision beam.In this paper,a front anti-collision beam of a car is taken as the research object.Under the condition of considering the process performance of the beam bending and forming process,the aluminum alloy anticollision beam structure-multi-objective optimization mathematical model of process parameters is established,and the optimal multi-objective genetic algorithm is obtained.Beam structural parameters and bending and forming process parameters.The main research contents of this paper are as follows:1)By comparing the mechanical properties of 7003 aluminum alloy under different heat treatment conditions,it is found that the strength of 7003-T6 aluminum alloy material is too high,and the bending and forming is difficult.The 7003-T4 aluminum alloy material has lower mechanical properties and better bending and forming properties.Therefore,in this paper,the aluminum alloy profile in the T4 state is first stretched and formed,and then the beam is brought to the T6 state by heat treatment.The mechanical properties of 7003 aluminum alloy were characterized by weighted combination of Swift hardening model and Hockett-Sherby hardening model,and the weighted hardening model parameters were solved.2)Based on the weighted hardening model of the material,the simulation analysis model of aluminum profile bending and forming is established,and the accuracy of the simulation analysis results is verified experimentally.The experimental results show that the results of the simulation analysis are in good agreement with the experimental results.At the same time,based on the premise of considering the genetic effect of the bending and forming,the simulation analysis model of the three-point bending and pendulum collision of the anti-collision beam is established.The analysis results show that the simulation results considering the genetic effect of the bending and forming are more consistent with the actual situation,and the simulation accuracy is higher.3)The minimum cross-sectional distortion of the anti-collision beam and the minimum distortion of the aluminum profile are taken as the target,and the springback and the maximum thinning rate are the constraints of the forming quality.The pendulum intrusion displacement is the stiffness constraint when the beam pendulum collides.The NSGA-II multi-objective genetic algorithm optimizes the distribution of the profile ribs,the thickness distribution,and the pre-tension and friction coefficient during the bending and forming,and finally obtains the Pareto optimal solution of the aluminum structure-process parameters.The reliability of the design results was verified by experiments.The experimental results show that the optimized anti-collision beam loses 0.747 kg,the section distortion variable decreases by 1.1mm,and the amount of depression after the beam pendulum collision is reduced by 0.7mm,indicating that the optimized beam is lighter in weight,collision performance and process performance.it is good.