Prediction of Forming Limit Diagrams (FLD) and Forming Limit Stress Diagrams (FLSD) for Aluminum Alloy 3105 with Finite Element Method using Ductile Fracture Criteria

Forming limit diagrams (FLDs) are very powerful tool for prediction of the formability of sheet metals. However, it has been shown that FLD diagrams are valid only for proportional loadings during which the ratio between the principal stresses remains constant throughout the forming process. Therefore, forming limit stress diagrams (FLSDs), which are independent of the straining path, have been developed. In this work, the forming limit diagram for aluminum alloy 3105 was first obtained experimentally using the Nakazima out-of-plane test. The forming limit stress diagram was then calculated by the application of plasticity theory. In addition, the FLDs and FLSDs for AA3105 were simulated using ABAUUS finite element software through the application of a ductile fracture criterion. The results showed that the diagrams obtained by the application of the ductile fracture criterion are relatively in good agreements with the experimental results, and hence, can be successfully used for the prediction of forming limit diagrams of the aluminum alloys.