Delamination mechanism of CFRP adhesive layer under laser-induced shock waves

• Increasing pulse energy and spot diameter helps CFRP interface delamination. • Larger thickness and curvature reduce the damage of adhesive layer. • Unconstrained back surface improves interfacial delamination. Adhesive repair is essential for restoring the structural integrity and mechanical performance of carbon fiber reinforced polymer (CFRP) components. After extended service, repaired structures require the removal of the adhesive patches for secondary repair. This paper investigates the interfacial damage of CFRP bonded components under laser-induced shock waves. The results show that the damage of CFRP bonding interface under laser-induced shock wave is due to the local tensile stress exceeding the tensile strength of the interface. The magnitude of local tensile stress depends on the superposition of incident wave and reflected wave at the bonding interface. Increasing pulse energy and spot diameter intensifies damage at the adhesive interface and reduces the interfacial tensile strength. As CFRP thickness increases, the interlayer tensile stress decreases, and the bonding interface damage is correspondingly reduced. Increasing curvature enlarges the angle between the reflected and incident stress wave at the bonding interface and the back surface, resulting in the reduction of the damage. Applying a metallic constraint to the rear surface of the specimen reduces the magnitude of the reflected tensile stress, thereby mitigating interfacial damage. Conversely, when the rear surface is unconstrained, the reflected tensile stress is higher, resulting in more pronounced interfacial damage.