Simulation of welding deformation for precision ship assembling (Report I)-In-plane deformation of butt welded plate

To realize automation and mechanization in shipbuilding industry, it is necessary to clarify the effects of various factors involved in the process and predict welding deformation in advance. As a first step of the studies, the in-plane transverse deformation of one-sided automatic welding is investigated. Numerical simulations have been done on real size plate using the thermal-elastic-plastic FEM method. Good agreement between computed results and measured results is obtained. The effects of various factors such as, local heating, welding sequence, initial stresses, type of tabs, pitch of tack welds and root gap have been investigated. Local heating affects the shrinkage deformation significantly near the heated region. Welding sequence also has a fairly large effect on the distribution of transverse shrinkage. Some patterns of initial stress in the plate could be an important factor that causes the statistical variation in the measured results.