Modeling of welding distortion in stiffened rings

A simple model is developed to describe the deformation of a ring stiffener under welding, with applications to submarine hulls. The model is based on the realization that only a small part of the structure near the welding arc (near field) undergoes high temperature changes, and thus behaves thermo-elastic-plastically, while the rest of the structure (far field) is elastic in nature. The model is used to predict the overall axisymmetric residual shrinkage of different rings and the results are shown to be in excellent agreement with the finite-element method (FEM). This concept of near and far field could also be used to simplify three-dimensional FE models when predicting local, asymmetric welding distortions of various geometry.