Control and optimization of bulge defect in incremental forming of cu-Al bimetal

摘要

Abstract The bimetal sheets products obtained by the incremental forming are gradually widely used because of the excellent properties of the bimetal sheets. But the forming process of the bimetal sheets is more complicated than that of single metal sheet because this process involves a complicated interface of the bimetal sheets. A three-dimensional model including the tool, the bimetal sheet and the cohesive element between the bimetal sheet has been suggested to discuss the bulge defect affecting the accuracy of incremental forming. And the analysis results have been compared with the experiment results to verify the correctness of the simulation model. The analysis show that the reason of bulge defect is the inconsistent stress state on the upper and lower surfaces of the sheet. Moreover, the results also indicate that the step down size is the most critical factor affecting the bulge height, the height of bulge defect increases by 133 as the step down size increase. In addition, it is found that different parameters also have a great impact on the interface status of the bimetal. Effecting optimization parameter have been proposed to reduce the bulge defect by 53.