Welding Distortion Analysis of Hull Blocks Using Equivalent Load Method Based on Inherent Strain; Final rept

摘要

This paper suggests an efficient method (Equivalent Load Method) for predicting the welding deformation of stiffened curved plates based on the inherent strain theory combined with the finite element method. The proposed method can predict the various modes of welding distortions of stiffened curved plates such as angular distortion, in-plane shrinkage, longitudinal and transverse bending deformations considering welding sequence according to the fabrication stages. The equivalent load was determined by integrating inherent strain components which are calculated in the vicinity of heat affected zone using the highest temperature and the degree of restraint. The welding distortions of curved stiffened panels under equivalent load were calculated by elastic analysis and compared with those by the experiment as well as the thermal elasto-plastic finite element analysis. The welding distortions of stiffened curved plates by the proposed method showed fairly good agreements with those by the experiment and intensive finite element analysis. It has been verified that the proposed method has a high efficiency and accuracy. By the proposed method, it was possible to predict the welding distortion of a curved double bottom block of actual ship. Due to its efficiency and accuracy, the present method can provide a powerful solution to predict the welding distortion of actual ship hull blocks with high complexity in structural shape.