Application of an Extended Strain-Based Forming Limit Curve in Finite Element Simulation of X-Branch Hydroforming

This work presents a numerical framework that implements extended forming limit curves (FLCs) to predict bursting during tube hydroforming process. Here, at first, the extended FLC is calculated for tube material based on the generalized M-K model that takes the through thickness normal stress into account. As a case study, the forming process of X-shaped branch is simulated by ABAQUS/EXPLICIT commercial finite element package. The required incremental plastic equivalent strain and strain ratio, which are required for comparison with the computed extended FLC, are extracted from the results of FE simulation. The robustness of the extended FLC in prediction of necking is tested by comparing with the published experimental data where a satisfactory agreement is found.