Optimal simultaneous welding to minimise welding deformation of a general ship grillage structure

Abstract

A precise estimation of the welding deformation is an essential process in improving steel fabrication processes for building ships and offshore structures. This study validated the effect of the optimal simultaneous welding on the mitigation of welding displacements. Most previous studies on the optimised welding sequence for the reducing welding displacements have focused on one welding line at each order. However, in heavy industries, several welders or robotic welding machines generally work together to efficiently spend work time. Herein, inherent strain theory is introduced to calculate the complex mechanical behaviour during a welding operation using the elastic finite element method (FEM). Multipoint constraint function and the interface element theory are employed to consider the relationship of the different welded parts. The impact of the optimal simultaneous welding in the sequence on the reduction of welding displacement is validated by using the proposed numerical method in the present study.