Effects of Different Absorption Models in the Damage Dimensions for High-Power Laser Irradiation of CFRP: Numerical Modeling and Experimental Validation

In the present study, the effects of three modes of reflection, namely, single reflection, multiple reflection and trapped reflection between the carbon fibers, on the removal of carbon fiber reinforced polymer (CFRP) is studied. Towards this, a finite element based numerical simulation methodology is established incorporating the chain of phenomena that occur in a CFRP panel, namely, polymer cross-linking (428 K – 568 K), epoxy burn off and pyrolysis (600 K – 723 K), material degradation (723 K – 906 K) and carbon fiber oxidation and removal (1273 K – 1798 K). The removal of the material by heat of ablation is modelled through a combination of deformed geometry and phase change approaches using the commercial software COMSOL MULTIPHYSICS®. The thermal damage of the fibers and the surrounding epoxy matrix is quantified in terms of the hole diameter at the top surface (TSH), the carbon oxidation diameter (COD), the epoxy damage diameter (EDD), and the heat-affected zone diameter (HAZ). The developed models are compared to the experimental results, which show that the predicted time required to make a through-hole and damage dimensions, based on the multiple reflection model, have a better agreement with the experimental results.