Yld2000-2D Parameters Identification With Heterogeneous Strain Field And Forming Limit Diagram For Aluminum Alloy

Aluminum alloy owns many excellent mechanical properties,such as high strength to weight ratio,high stiffness and corrosion resistance.Hence it is widely used in automotive and aerospace manufacturing fields.The advanced material constitutive model and accurate forming limit curves are vital in guiding the aluminum alloy application.In this work,a new biaxial tensile test platform was designed,and the constitutive model and accurate forming limit diagram of aluminum alloy were investigated.(1)A biaxial tensile test platform was designed,which included the mechanical biaxial tension device,the experimental data collection system and the heating system.With this platform,the biaxial tensile test can be carried out under various tensile ratios and high temperatures.(2)The parameters of Voce hardening and Johnson-Cook damage criterion for 1420 aluminum alloy were identified by a series of uniaxial tensile tests.The parameters of YId2000-2D yield criterion were obtained by an inverse identification method with heterogeneous strain field.Subsequently,the forming limit curves of 1420 aluminum alloy were investigated by biaxial tensile test and finite element simulation.(3)Based on the thermal uniaxial tensile test,the effects of temperature on the flow stress and anisotropy behaviour of 7075 aluminum alloy were investigated.In addition,based on the thermal biaxial tensile test,the forming limit curves of 7075 aluminum alloy at necking and fracture under 200? were investigated.(4)With a self-designed electrical heating system,the parameters of Voce hardening and Hill'48 yield criterion for 7B04 aluminum alloy were identified by uniaxial tensile tests.By adopting the Pottier test,a heterogeneous strain field was generated.Based on the inverse identification method with the heterogeneous strain field,the parameters of Yld2000-2D yield criterion were obtained.Finally,in order to verify the precision of the identified Hill'48 and Yld2000-2D yield criteria,a deep drawing test and its finite element simulation were carried out.