Simulation of Postwelding Distortion Control of Stiffened Hull Blocks by Line Heating

Abstract

The objective of this study is to develop an analysis method to predict the reduction of welding distortion of stiffened plates by line heating. The equivalent loading method, based on the inherent strain theory, was established to analyze the heat straightening of stiffened plates. The heat input for the analysis was obtained based on experimental temperature variation curves. Temperature distributions during two- line heating process were calculated by two-dimensional heat transfer analysis using the finite element method. The degree of restraints was estimated by combining the experimental data of simple specimen and unit loading analysis. Equivalent loads were obtained by integrating the inherent strains, which were determined from the highest temperature and the degree of restraint. Finally, the equivalent loads obtained were imposed, as applied loads, on the elastic analysis to predict the reduction of welding deformation in stiffened plates. If the basic experiments for several simple cases are carried out, the proposed method can be extended to the analysis of heat straightening of welding distortion of more complicated stiffened plates and ship hull blocks.