Three-dimensional transient heat conduction and thermomechanical analysis for laser spot welding using adaptive heat source

Numerical modelling of laser spot welding process as an aid to design for welding has gained significant attention in the recent past, because experimental measurements of peak temperature and weld thermal cycle are expensive and often intractable. Accurate knowledge of the temperature history in the weld pool and the surrounding solid substrate are a prerequisite for the estimation of weld joint strength. The present work proposes a three-dimensional (3D) transient conduction heat transfer based coupled thermomechanical analysis of laser spot welding process. To accommodate enhanced heat transfer in weld pool at higher temperature owing to convective flow and greater amount of absorption of the laser energy, an expression for a volumetric heat source that is dimensionally similar to the transient weld pool is considered. The calculated weld pool dimensions have shown fair agreement with similar measured values reported in previous literatures. The calculated weld thermal cycles are subsequently used to calculate distortion and thermal stresses considering a typical butt joint geometry.