Finite Element Analysis Of Creep Age Forming For Aluminum Alloy2124

Abstract:Creep age forming as a kind of forming technology which combined age-hardening and creep into one process has been widely used in modern aerospace industry. Also it was considered to be a important forming technology for the wing skin with large-size, single/double curvature and variable thickness shape in China’s "Large Aircraft" project.2124aluminum alloy has been used in manufacture the lower wing skin because of good toughness, good fatigue properties and good thermal stability. So we take it as research object in this paper. A unified creep constitutive model was established based on the uniaxial tensile creep experiments and then explored the influence of technical parameters on the aging process of the single/double curvature, variable thickness component’s springback. The results are as follows:(1) Creep constitutive model has been developed which can describe the2124aluminum alloy. The material parameters within the equation were determined by using numerical fitting software Close agreement between the predicted and experimental creep curves has been achieved.The constitutive model is: H=(m/σ)(1-H/H*)εc(2) The expression of constitutive model under multi-axis force conditions was derived and implemented into ABAQUS through the user-defined subroutine CREEP. Contrast experimental and numerical results indicate that the constitutive model can well predict the springback of CAF under different conditions.(3). Numeric iteration compensation model was used to virtual the springback into the single curvature/variable thickness component CAF process,which was simulated by using the ABAQUS software. The final springback error of the measured and calculated is less than4%, show that the proposed constitutive and numeric iteration compensation model can be used to guide similar CAF process.(4) The effect of thickness, pre-bending radius and reep aging time on the sheet’s springback was researched by finite element software. The results show that:In the case of the same aging temperature, aging time and shape factor S (ratio of thickness h and average curvature radius Rm,ie S=h/RM), the springback was also unchanged.