Fourier series-based implicit Fem program for axisymmetric analysis of tube hydroforming

Tube Hydroforming has become a preferred alternative to stamping and joining processes in industry for manufacturing closed cross section structural components. This process requires proper combination of part design, material selection, application of internal pressure and axial feeding. By using finite element analysis, these process parameters can be determined efficiently in the very early stage of production.; The thesis presents a Fourier series based axisymmetric analysis of Tube Hydroforming. The material is assumed to elastic-plastic and to satisfy the plasticity model that takes into account rate independent work hardening and normal anisotropy. Numerical solution obtained from Total-Lagrangian formulation of general shell theory is employed. The axial stroke is incorporated using Lagrange multipliers. Contact violation and boundary friction condition are introduced into the formulation based on penalty functions, which impose constraints directly into the tangent stiffness matrix. The Force Limiting Curves based on shear instability and on experimental results are used as fracture criteria. The Axisymmetric Hydroforming program developed is verified against results from Abaqus and experimental measurements for isotropic and anisotropic (transverse) materials.