Study of Temperature Field Considering Gradient Volumetric Heat Absorption inTransparent Sheet During Laser Transmission Welding (LTW)
D.K. Goyal, R. Yadav and R. Kant
A more realistic volumetric heat flux gradient is considered for the distribution of laser beam energy in the upper transparent part to precisely estimate the temperature distribution in laser transmission welding (LTW). A three-dimensional (3-D) finite element (FE)-based numerical model is developed to model the laser heat absorption in the upper transparent sheet and at the joining interface of the sheets by incorporating a varying Gaussian beam diameter as a function of stand-off distance, beam quality factor, laser wavelength and sheet thickness. The numerical model is validated by comparing the surface temperature with the experiments. The surface temperature obtained from the developed numerical model having volumetric and surface heat flux are compared with the surface heat flux model. The surface temperature results show that the developed numerical model estimates the temperature more closely with the experimental results and reveals that the temperature at the interface is affected negligibly by taking gradient volumetric heat absorption into consideration.
Keywords: Fibre laser, polycarbonate (PC), electrolytic iron powder (EIP), laser transmission welding (LTW), volumetric heat absorption, finite element (FE) model, interface temperature, stand-off distance