Effect of Thermal Distribution and Stiffness Variation on Welding Distortion in a Ship Panel Structure

In this paper, the effects of thermal distribution and stiffness of plate on welding distortions in a ship panel structure for various welding sequences are simulated by finite element analysis using ANSYS software. The simulation consists of a three-dimensional transient and nonlinear sequentially coupled thermo-mechanical analysis using an element birth and death (EBD) technique for simulating filler metal deposition. A macrocode programmed based on Goldak model is developed to apply thermal loading generated by the heat sources. At first case, the model of ship panel structure is simulated, and then welding sequence on ship panel structure is applied and welding distortion is determined. In this case, only the effect of thermal distribution on welding distortion is being calculated. At second case, an EBD technique is being used to simulate the stiffeners in death state. So welding of each stiffener to the plate is simulated as a stiffener in birth state. In this case, not only the effect of thermal distribution is calculated but also the effect of plate stiffness variation is determined. Finally, the comparison between the mentioned cases proves that the effect of plate stiffness variation on distortion features in ship panel structures is very lower than the thermal distribution.