Combined Solution for Critical Damage Determination and Fracture Prediction in AA1050-O Alloy Sheets

The prediction of damage for each material during plastic deformation processes is crucial yet challenging due to the significant variability of prediction results according to ductile fracture criteria. This paper presents a solution for determining the critical damage values of AA1050-O aluminum alloy sheets as well as predicting workpiece damage in combined deep drawing processes using a combination of experiments and numerical simulations based on Freudenthal, Cockroft-Latham, and normalized Cockroft-Latham ductile fracture criteria. First, the depth of indent obtained from the Erichsen cupping test was applied to identify the critical values through numerical simulation using the Freudenthal, Cockroft-Latham, and normalized Cockroft-Latham ductile fracture criteria. Then, the critical values were used to predict the fracture for AA1050-O alloy sheets in the combined deep drawing processes. The prediction was validated through the execution of a combined deep drawing process experiment on AA1050-O alloy sheets employing a hydraulic press. The results demonstrated the superiority of the Cockroft-Latham criterion over other criteria in predicting both failure and non-failure occurrences in the combined deep drawing processes of AA1050-O alloy sheets, particularly in forecasting failure initiation, moment, and position. The combination of experiments and numerical simulations exhibited its potential to predict fracture criteria in other forming processes. © The Minerals, Metals & Materials Society and ASM International 2024.