Numerical-Experimental Investigation of surface integrity and kerf characteristics in laser cutting of GFRP using a conical Gaussian heat source

Abstract

Laser processing of GFRP composites generates a heat‑affected zone (HAZ) which will affect surface roughness and mechanical properties. Conventional heat source models do not consider the Gaussian distribution of heat flux in the thickness direction. This limitation affects the simulation of kerf characteristics and HAZ width. This study establishes a finite element model using a Gaussian conical volume heat flux. This model accounts for energy distribution along the material thickness. The laser source utilized in this work is a TruFiber 6000 pulsed fibre laser, operating at a central wavelength of 1071 nm. The heat source moves with APDL command streams. Birth‑death element technology simulates material removal. In addition, surface roughness is predicted using the least‑squares reference plane method. Node coordinates are extracted from the cut surface. Parametric studies reveal clear trends. HAZ width increases from 101 µm to 138 µm when cutting speed rises from 50 to 250 mm/s. It increases from 88 µm to 137 µm when laser power rises from 1200 to 2000 W. Focal position shows an initial decrease then increase in HAZ width. The optimal focal position is − 3 mm, giving the smallest HAZ (108 µm). The simulation results match experimental data well, with relative error mostly below 5 %. With optimal parameters (150 mm/s, 1600 W, −3 mm), the kerf edges are well‑defined, the HAZ is narrow, and surface roughness is reduced. This model provides an effective tool for parameter optimization. It helps improve processing quality and reduce damage in GFRP laser cutting, which is important for automotive light weighting and other industrial applications.