Finite element modelling and experimental validation of laser transmission welding of oak wood fiber reinforced polypropylene composite

Finite element analysis (FEA) was performed to determine the weld width in laser transmission welding for three different configurations. The first configuration involved joining a 100% pure polypropylene transparent part to an absorbent part doped with 0.2 wt% carbon black, without fiber reinforcement. The second configuration incorporated 15 wt% natural fiber into the absorbent part, while the third configuration incorporated 15 wt% natural fiber into the transparent part. The FEA employed a 3D subroutine heat source accounting for thermal convection, conduction, and radiation, run within the ABAQUS software. Material properties were obtained through various methods. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to assess thermal stability and specific heat capacity. Optical properties, including transmittance, reflectance, and absorbance, were measured experimentally using near-infrared spectroscopy and integrated into the model. The effective thermal conductivity of fiber-reinforced polypropylene was calculated using homogenization of a representative volume element (RVE) in ABAQUS, while density was determined using the rule of mixtures (ROM). Upon completion of the simulations, the predicted weld widths were compared with the experimental results.