Research of Directional Stress Distribution on the Fully Plastic Bulged Pressure Hull

Abstract

In order to improve the ultimate capacity of pressure hull, a new method to improve the external bearing limit is put forward and residual stress is used. Based on the lame formula, the bilinear hardening model is considered to deduce the residual stress formula. Two influence parameters are analyzed by theoretical and numerical methods. The accordance of results shows that the accuracy of theoretical derivation can be verified by FEM. The 3D models with residual stress or not are built in ABAQUS. According to a lot of data of simulation experiments, the result indicates that the directional residual stress is useful, especially compressive on the outer surface of the pipe and the hoop stress keeps tensile on the inside surface. This kind of stress distribution is helpful to the cylinder structure and can improve its ultimate capacity of external pressure. Thus, the formula considering hardening material can guide the full plastic bulging to produce the desired stress distribution.