| Hydroforming of metal components is widely used in several industries. While numerous variations of hydroforming exist, the basic principle remains the same: utilize fluid pressure to form a component. In tube hydroforming, internal pressure is applied to form a tubular metal blank into a structural component having a closed cross section.; The thesis presents a "cross-section" analysis method for calculating tube stretching and bending followed by hydroforming and expansion to fill the die in the hydroforming process. The material is assumed to be elastic-plastic and to satisfy the plasticity model that takes into account rate-independent, work hardening and normal anisotropy. Based on the virtual work principle and constitutive equation, the equilibrium equation can be derived. Numerical solution obtained from a Total-Lagrangian formulation of a general shell theory is employed. The boundary friction condition is introduced into the formulation in the form of penalty function, which imposes the constraints directly into the tangent stiffness matrix. The Newton-Raphson algorithm is used to solve the nonlinear equation. |
