Dynamic modeling of the interfacial bonding strength of CFRP composites detected by laser shockwave

Abstract

The bonding interface serves as the stress load transfer surface of the key bonding structural component of offshore engineering equipment, making its quality detection crucial for ensuring strength and service safety. The laser shock adhesion test is an effective method to detect the bonding quality in the local range by pulsed laser-induced high strain rate shockwave. However, this process requires attention to the propagation and failure mechanism of shockwaves to better understand the energy reference level of spalling in bonded structures. Under laser shock, a combination of simulation and experimental methods was employed to investigate the impact of laser energy and pulse width on the damage characteristics of symmetrically bonded laminated plates with varying thicknesses of bonding plates, elucidating the layered damage mechanism induced by laser shock. It has been observed that the thickness of the bonding plate exhibits a correlation with both the location of damage and the laser energy threshold, under unchanged laser parameters. The thicker the bonding plate, the higher the laser energy threshold becomes, and gradually, the initial location of damage shifts from the impact back to the adhesive layer. With the increase of pulse width, the damage location of the spalling moves from the impact back to the impact surface, and the spalling area increases. The thicker the bonding plate of the symmetrical bonded structure, the greater the selected pulse width, which can enhance spalling effectiveness. Laser energy plays a crucial role in determining spalling outcomes, with higher laser energy resulting in increased spalling damage. The modulation of laser energy and pulse width offers a viable approach for employing the laser shock adhesion testing in non-destructive testing of weak bonding within different material thicknesses composite material bonded structures.