Research On Formability Of Aluminum Alloy Stamping Sheet Based On FLD Under Warm Molding Conditions

With the economic development,people’s living standards continue to increase,and the car ownership and production and sales volume in our country also rise.As a result,more serious problems such as environmental pollution and insufficient energy are brought about.In order to solve these problems and achieve the purpose of energy conservation and emission reduction,light weight materials have emerged.Therefore,lightweight materials have gradually become the focus of academic research at home and abroad.Although the aluminum alloy is excellent in performance,it is difficult to form at room temperature and it is difficult to reform it by cold forming.In view of this,the aluminum alloy can be formed by warm forming Its processing for other components.The Forming Limit Diagram(FLD)is usually used to analyze the simulation and fracture of sheet metal stamping,which is one of the important conditions for determining the formability CAE analysis of sheet metal.Under the thermoforming standard,the FLD with a thermoforming environment is conducive to the sheet metal formability of the aluminum alloy sheet during the stamping process.In both domestic and foreign countries,there is a lack of in-depth discussion on FLD in thermoforming environment.In addition,thermoforming has high requirements on experimental conditions and experimental temperature,so it can not obtain fully compliant FLD.Finally,Resulting in a certain gap between theoretical results and experimental results.Therefore,research on the influencing factors of FLD in warm forming environment has important practical significance for obtaining and using accurate FLD.The finite element model of 5754 aluminum alloy FLD experiment described in this paper is based on FLD experiments and experimental results of 5754 aluminum alloy in a thermoforming environment.The experimental results and simulation results are compared to verify the correctness of the model.In the FLD experiment,the screening and comparison of the three kinds of drawbead finite element models and the screening of the 5753 aluminum alloy material model and the finite element simulation with equivalent drawbead are the focuses of this article.Secondly,using the correct finite element model,the simulation was carried out to investigate the effect of FLD experiment on the accuracy of FLD in thermoforming environment and to quantify the experimental gap.The core of this study lies in the influence of FLD on the friction coefficient and geometrical size of the FLD experiment in all five aspects.The influence of the uniaxial tensile strain,the plane strain state,the specimen fracture position,the overall as well as the biaxial tensile strain state in the FLD experiment Belong to the analysis of the key elements.The conclusion of the research is not only the premise of the specific use of aluminum alloy in the car body,but also provides a more accurate basis for judging the formability of the aluminum alloy in the thermoforming environment.Finally,in a warm forming environment,the simulation was discussed based on FLD set to adjust the experimental gap,in-depth discussion of 5754 aluminum alloy door panel stamping formability.The results show that: firstly,in order to improve the calculation speed,the virtual stamping efficiency can be improved within a certain range,and the efficiency of virtual stamping does not change the accuracy of the simulation.Second,in order to improve the forming quality of sheet metal,Wrinkling and other shortcomings in the forming process,can be achieved by adding drawbead method.