Mechanical Weld Zone Characterization for the Numerical Simulation of Forming Friction Stir Welded Aluminum Blanks

摘要

In order to predict the warm formability of friction stir welded aluminum sheets, a new approach for the mechanical characterization at elevated temperature is presented in this paper. Based on warm tensile test and biaxial tensile test local properties of base material and weld nugget material were determined by using specimens with reduced measuring areas. Special characterization specimens are designed according to the weld zone dimensions and numerically optimized to guarantee homogeneous stress distribution. Identified material parameters were used to build up local material models based on approximated flow curves and an anisotropic yield function. The ability of predicting the formability performance of welded sheets was finally evaluated by the validation of numerical simulations with experimental results in dome stretching tests.