Concurrent Effect of Laser Texturing and Resin Pre-Coating on the Performance of CFRP Single Lap Joints

Adhesive bonding is increasingly used in lightweight structural applications, though its effectiveness for carbon fiber reinforced polymers is often limited by low surface energy. This study investigates the concurrent effect of infrared laser surface texturing and resin pre-coating on the mechanical performance of carbon fiber-reinforced polymer single-lap joints. Using a CO2 laser system, micro-dimples were generated on the substrate to promote mechanical interlocking, while various concentrations of an epoxy resin (5 wt%, 10 wt%, and 20 wt%) were applied as precoating to enhance surface wetting and interfacial continuity. To validate the experimental findings, a numerical investigation was performed using a Cohesive Zone Model implemented within a finite element framework. This model utilized a bilinear traction-separation law and a quadratic delamination criterion to predict the progressive debonding and failure of the interface. Experimental results indicate that the 10 wt% resin pre-coating concentration provides the highest lap shear strength.