Analysis of hydrostatic tube bulging with cylindrical die using static explicit FEM

Tube Hydroforming (THF) is getting an increasing amount of attention in industry. THF has advantages such as weight reduction, high dimensional accuracy, and high rigidity. However, this forming process requires precise control of internal pressure and axial feeding. Additionally, in most cases prebending processes must be performed on the tubes before the hydroforming process can be carried out, and the forming ability of the hydroforming processes is influenced by the outcome of this prebending process. We describe the development of the Finite Element Method (FEM) code for THF analysis and a comparison of experimental and analytical results. The elastoplastic FEM code for THF analysis has been developed based on ITAS3D which is a sheet-metal-forming simulation program using the static explicit method. The algorithm of hydraulic pressure has been newly implemented in ITAS3D. Hydrostatic copper tube bulging with a cylindrical die was calculated with the code, and analytical results show good agreement with experimental ones. In this calculation, there is only a very small difference between the solid element and shell element results.