Damage characterization and discrimination in laser-shocked carbon fiber reinforced polymer laminates: A mass-spring-damping model approach

Laser bond inspection (LBI) plays a crucial role in the assessment of interfacial bond strength. However, the development of damage by laser parameters influences the detection and identification of damage. To overcome this challenge, this paper develops a “mass-spring-damping” response model for laser-shocked CFRP laminates and proposes a new damage characterization parameter “R”. The effects of laser parameters on damage are investigated in the range of 20∼300 ns laser pulse width, 2 and 5 mm laser spot diameters and 0∼6 J laser energy on a 1.5 mm thick T300/AK8210 CFRP laminate. And by combining the parameter “R” with the laser parameters, the corresponding damage pattern curves can be obtained and the internal damage can be characterized by dividing the four damage stages by the extreme points. Based on the pattern curve, a new analysis method is proposed and a laser shock damage discrimination model is constructed. The model can get the damage pattern curve of this specimen under 5 mm spot diameter and any pulse width within 20∼300 ns, so as to achieve the damage characterization and damage prediction. Relative error between predicted and true results within 9%.