Effect of laser ablation on mechanical performance of graphene-filled glass fibre reinforced polymer repaired composites

Abstract This paper aims to investigate the effect of laser ablation on the mechanical performance of graphene-filled glass fibre reinforced polymer (GFRP) repaired lap joints. The performance characteristics of repaired laminates were measured in terms of surface roughness, tensile strength and flexural strength according to ASTM standards. While the surface morphology was examined using a confocal microscope, scanning electron microscopy was adopted to analyse the laser ablated fibre–matrix interface. The average surface roughness significantly increased with an increase in laser power from 4 to 10 W which was attributed to the presence of graphene and burnt fibres. The laser ablation conditions corresponding to 10 W laser power, 300 mm s −1 scanning speed, 20 kHz of pulse frequency, 0.05 mm line spacing and 5 laser passes lead to the highest tensile strength (36.033 MPa) and bending strength (30.972 MPa) of GFRP laminates. The laser ablated microstructure was characterised by fibre pull-out, epoxy residue, burnt, clean fibres as evidenced by scanning electron microscopy.