Effect of laser generated microgrooves geometric parameters on the shear strength of CFRP-Aluminium alloy adhesive joints

The surface microstructure is one of the most important factors affecting the mechanical performance of adhesive bonding joint of CFRP materials. The aim of this paper mainly focused on the influence of laser generated microgrooves geometric parameters (groove depth, distances, and patterns) on the shearing strength of CFRP/aluminium alloy adhesive joints. An IR laser with a wavelength of 1064 nm was applied to pretreat the CFRP surface. Scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM) were used to observe and measure the surface morphology, cross-sectional shape, groove parameters (depth, width) and surface roughness. The single-lap shear experiments were also conducted to exam the quality of the adhesive joint. Meanwhile, failure modes under different groove parameters were examined using a digital camera. The main parameters of the grooves and their interaction effects on the final joint strength were quantitatively analyzed by an interactive orthogonal experimental design. It was concluded that the interaction of groove pattern and groove distance was the most significant factor affecting shear strength, followed by groove pattern and groove distance.