Experimental study of FLD0 for aluminum alloy using digital image correlation with modified ISO method

Abstract

AbstractA new material's forming limit diagram (FLD) must be obtained before it can be used for stampings. Compared to conventional methods, the ISO method with a digital image correlation system provides an efficient way to conduct these tests. However the ISO method is position dependent, so the evaluation procedure for aluminum alloy will be seriously affected by the multiple necking strain distribution, resulting in much error. In this paper, a modified ISO method, which can be used for the evaluation of the aluminum alloy FLD, is proposed, and errors resulting from multiple necking were eliminated through detection of the major necking area. An FLD evaluation software was also programmed. An FLD0 punch test was conducted to verify the new modified ISO method. Through comparison of the results with the accepted value, the FLD0 value evaluated from the modified method was determined to be much more accurate than the standard method.