Numerical Investigation on Weld Induced Imperfections in Aluminium Ship Plates

The present work aims at better understanding and predicting the thermal and structural responses of aluminium components subjected to welding, contributing to the design and fabrication of aluminium ships such as catamarans, lifesaving boats, tourist ships and fast ships used in transportation or in military applications. Taken into consideration the moving heat source in MIG welding, finite element models of plates made of aluminium alloy are established and validated against published experimental results. Considering the temperature-dependent thermal and mechanical properties of the aluminium alloy, thermo-elasto-plastic finite element analyses are performed to determine the size of the heat affected zone (HAZ), the temperature histories, the distortions and the distributions of residual stresses induced by the welding process. The effects of the material properties on the finite element analyses are discussed, and a simplified model is proposed to represent the material properties based on their values at room temperature.