Reserach On Warm Formability Of Aluminum Alloy Tailor Welded Blanks For Body Cover

Automobile industry is the second largest industry in China,which is the backbone of our national economy.With the rapid growth of automobile ownership,it has brought huge challenges to the oil safety and environmental protection of our country.China’s dependence on foreign oil has gradually increased and it is imperative to reduce the weight of automobiles to save energy and reduce emissions.Aluminum alloy has low density and high strength,which is an excellent lightweight material.Considering the direction of material lightweight and structure lightweight,this article mainly studies the warm forming ability of 7075-T6 aluminum alloy friction stir tailor welded blanks for body cover.Firstly,through the method of high temperature tensile tests,the stress-strain curves of aluminum alloy tailor welded blanks at different temperatures and different strain rates are obtained.A high temperature constitutive model suitable for aluminum alloy tailor welded blanks is constructed,and the error analysis of the model prediction results is carried out.The obtained constitutive model can accurately describe the mechanical properties of aluminum alloy tailor welded blanks.Secondly,the change of micro-voids during the tensile process is analyzed.The high temperature tensile test process is simulated,and the damage parameters of aluminum alloy tailor welded blanks is determined through the finite element reverse calibration method.The tensile simulation based on the damage parameters can accurately predict the fracture position and the maximum stress.Finally,based on the determined constitutive relationship and damage parameters,the warm forming simulation of aluminum alloy tailor welded blanks is performed to simulate the thermal-mechanical coupling in the forming process.And the prediction of cracking position after forming is carried out to explore the influence of forming parameters on the forming effect.When the temperature is 350℃ and the blank holder force is 10 kN,the ideal forming effect can be obtained.Properly increasing the fillet size can also improve the forming effect.In this article,through the combination of theory and simulation,the constitutive relationship and damage parameters of aluminum alloy tailor welded blanks that can be used for forming simulation are determined,and the warm forming simulation is carried out to improve the possibility of the application of aluminum alloy tailor welded blanks in body cover.It’s helpful to improve the level of vehicle lightweight.