A two-dimensional approach for simulation of hydroforming expansion of tubular cross-sections without axial feed

Abstract

A new two-dimensional numerical method is developed based on membrane analogy to tube-sheet deformation with the concept of finite elements for sheet discretization, while utilizing a kinematically admissible approach to derive explicit expressions for relating loads and deformation. Typical tube cross-sections can be modeled using this approach. A new concept of controlling region and direction is proposed to track the deformation in different regions of the cross-section. Sticking friction is considered and a power-law model is used to express the deformation behavior of material. The new method is verified using commercially available FEA packages. The results show that it is computationally efficient and would prove to be an important tool for the process designer to interactively study the parameters on the process. The current formulation can predict the pressure load requirements and final thickness distribution for most polygon shaped tubular cross-sections.