Numerical study of laser diode transmission welding of a polypropylene mini-tank: Temperature field and residual stresses distribution

The aim of the present work is to predict the temperature field and the residual stress distribution generated after the Laser Diode Transmission Welding process of a mini-tank. The studied material is a commercial polypropylene (PP). The Drucker-Prager yield criterion was adopted to take into account the effect of the hydrostatic pressure on such residual stress distribution. The results obtained have revealed bending phenomena during the laser welding process, with a degree of deflection depending on both the clamping pressure and the temperature generated during welding. Moreover, it has been shown that the spring-back phenomena of the welded specimen can be better described by the use of the time-dependent thermal properties of the material used.