Return mapping algorithm for elasto-plastic deformation of thin walled pipes

Return mapping algorithms are popular procedures for evaluating elasto-plastic material behaviour. This paper presents a dedicated return mapping algorithm for thin walled pipes and vessels with Von Mises plasticity and isotropic hardening, for which it can be assumed that the hoop stress is constant. This applies for example to pipe line sections during offshore laying operations. In the algorithm a nonlinear scalar equation is solved iteratively. A general 3D radial return mapping algorithm with an iteration loop to fulfil the assumptions on hoop and radial stress is used to verify results obtained with the dedicated algorithm. Results of both algorithms are identical, while the new algorithm is more efficient.