Improving the prediction of springback behavior in aluminum outer panel sheets by finite element method

In this thesis study; springback, which is one of the most common problems in the forming of aluminum outer panel sheets in the automotive industry, is discussed. The finite element method was used to determine the springback behavior before the production line. Mechanical tests were carried out to determine the parameters used in the simulation. With the data obtained from these tests, it is aimed to improve the prediction of springback behavior by using different material and friction models. Roof part and AA6016 material were selected to examine the springback behavior of aluminum outer panel sheets. For AA6016 material, the parameters of Swift/ Hockett Sherby - Barlat89, Swift/ Hockett Sherby -BBC 2005 and Yoshida Uemori - BBC 2005 models were obtained through experimental data (hardening curve, yield surface and forming limit curve parameters). It has been observed that the correct selection of the friction model is very important in the prediction of springback behavior for the aluminum outer panel. Springback behaviors were investigated by using different friction models (constant friction coefficient Autoform Triboform friction model, pressure dependent friction model and mixed friction model) in simulation studies. As a result of the studies, it was seen that Autoform Triboform on the female and male die surfaces used together with the Yoshida Uemori - BBC 2005 material model and the pressure-dependent constant friction coefficient on the female and blankholder surfaces gave the best results in the prediction of springback.