One of the most disturbing aspects in structural assembly is welding distortion. These deformations adversely affect the subsequent fit-up and alignment of the adjacent panels. The extent of distortion depends on welding parameters, plate thickness, thermophysical properties of plate material, structural restraints, and welding sequence. Because welding is a fully transient phenomenon, its numerical analysis is highly time consuming, and hence analysis of full-size ship structural panels is simply not feasible using conventional finite element (FE) analysis. The computational time depends on number of elements, type of analysis, number of load steps, and computer configuration. Actual simulation of welding, that is, transient elastoplastic thermomechanical analysis is computationally highly time consumable. In the present study, two different modeling approaches for welding distortion prediction are presented that show a drastic reduction in computational time. Finally, comparative studies are made among the transient elastoplastic thermomechanical analysis and two different equivalent techniques, that is, inherent strain method and transient cooling phase analysis for prediction of welding distortions of a stiffened plate panel.