Bonding quality detection of composite structure by laser shock wave

Abstract

The carbon fiber reinforced polymer (CFRP) is more and more attractive because of its excellent mechanical performances, while the application of CFRP is limited because the non-destructive evaluation method is still not well done. A method based on shock waves produced by a pulsed laser is applied to the evaluation of bond quality of CFRP plates joined by an adhesive layer. A laser shock wave can cause a tension when it propagates through the adhesive/plate interface. A good bond will be unaffected by a certain level of shock wave stress whereas a weaker one will be damaged. In the experiments, the sample surface velocities are optically measured with an interferometer. The signals give a signature of well-bond or bad ones, and are used to obtain an estimate of the bond strength. Results show that the proposed test is able to differentiate bond quality. Laser-ultrasonic measurements made on shocked samples also confirm that weak bonds are revealed by the laser shock wave. The development of this technique will probably make the on line evaluation of CFRP structure possible in the future.Peer reviewed: YesNRC publication: Ye