Numerical prediction of welding deformation in ship block subassemblies via the inhomogeneous inherent strain method

The weld length of ship block subassemblies is several meters even tens of meters long, mainly welded by arc welding. The inherent strain method, applying the same inherent strain value in the welding direction, is typically used in the welding deformation prediction of ship block subassemblies with high efficiency. However, the inherent strain is inhomogeneously distributed in the welding direction, especially for welds with large lengths, causing the accuracy of the inherent strain method cannot meet the need for welding deformation prediction of ship block subassemblies. This paper proposes an inhomogeneous inherent strain method (IHISM) by considering the tensile effect of the solidified zone of the weld on the melted zone. In IHISM, the magnitude of the inherent strain is related to the length of the weld. The inhomogeneous inherent strain value is obtained from a thermal elastic-plastic (TEP) finite element method and experiments. Moreover, different experiments are performed to verify the accuracy and efficiency of the IHISM. Compared with the TEP analysis, the IHISM can reach a similar accuracy while greatly improving computational efficiency. Compared with the conventional inherent strain method, the accuracy of IHISM is higher in terms of deformation trend prediction and relative deviation.