Prediction of rupture in tube hydro-forming process using ductile damage

Abstract

Determination of forming limit in sheet metal forming processes is very important and can reduce the number of costly trials. Therefore numerous numerical and experimental analyses have been reported. In this paper, 3D model of hydro-forming process of T-shape tube was simulated by finite element method. An integral ductile damage model, coupled with von Mises plastic criterion, has been applied to predict where and when onset of ductile rupture occurs in the process. Model is based on damage evolution and accounts nonlinear strain paths. Results have been compared with experimental tests and empirical observations. Because of bending effects and nonlinear strain paths assumptions, the ductile damage model showed good agreement with experimental tests and empirical observations. The results were satisfactory and acceptable. Hence ductile damage model can be used as a reliable criterion in prediction of ductile fracture in sheet metal forming processes.