Deformation Behavior Of Aluminum Alloy Anti-collision Beam System Under Dynamic And Static Loading And Optimum Design Of Profile Wall Thickness

Aluminum alloy is a type of lightweight alloy material with high specific strength and corrosion resistance.It has been extensively used in automobiles,ships,aerospace and other transportation vehicles in recent years.At the same time,it has been the preferred lightweight material for automobiles.The anti-collision beam system mainly occurred compression deformation and bending deformation in the accident.Aiming at these two deformation conditions,the hardening model used in the simulation was obtained by combining experiment with numerical simulation.The deformation behavior and lightweight design of the aluminum alloy anti-collision beam system are studied,which provides a way for the design,development and application of the aluminum alloy profile.（1）The mechanical properties of 6 series aluminium alloys were obtained by quasi-static and high-speed tension,the yield strength,tensile strength and elongation of 6082-T6 aluminum alloy are higher than those of 6063-T6 aluminum alloy;6063-T6 has no obvious strain rate sensitivity,6082-T6 has obvious strain rate sensitivity when the strain rate range from 0.001s^-1 to 200s^-1.The deformation behavior of aluminum alloy is predicted by hardening model.The parameters of SHS hardening model are obtained by combining the numerical simulation and experimental results of quasi-static and high-speed tension.The accuracy of SHS hardening model is verified by comparing the crushing test and nume rical simulation results of energy absorbing box.（2）Aluminum alloy anti-collision beam system is always taken as the research object,and the hardening model is substituted into three-point static pressure,pendulum impact and 13 km/h low-speed collision numerical simulation to predict the deformation behavior of the anti-collision beam system.The numerical results,such as the force-displacement curves of three-point static pressure,the displacement change of the back end of the anti-collision beam in pendulum impact and the acceleration-time curve of low-speed collision as well as deformation,are in good agreement with experimental.The results show that the numerical simulation can effectively predict the deformation behavior of the aluminum alloy an ti-collision beam system.（3）Based on the results of low-speed collision simulation,the multi-objective optimization method is used to optimize the design of anti-collision beam assembly.Taking the wall thickness of the anti-collision beam and energy absorbing box as optimization design variables,taking the total energy absorbed by the anti-collision beam system and the deformation in the collision process as constraints,the peak of acceleration and mass as objective functions,the response surface methodology approximation model and the radial basis function approximation model are established.The Pareto frontier solution of multi-objective optimization is obtained by NSGA-II optimization algorithm.The results show that the 0.697kg weight of the aluminum alloy anti-collision beam system was reduced,and the peak acceleration decreases by 17.1%.The results of multi-objective optimization design are obtained.