LASER BOND INSPECTION FOR ADHESIVE BOND STRENGTH

摘要

Advancements in manufacturing and assembly methods to reduce cost and increase rate arepushing for the application of adhesive bonding in carbon fiber reinforced plastic (CFRP)primary structure applications. Both CFRP to CFRP and CFRP to metal bonds are underconsideration. In these cases, the certification of the structure requires total confidence in the asmanufactured strength of the adhesion in the joint. Unfortunately, there are no standardnondestructive inspection (NDI) methods that can return a value for the bond strength. LaserBond Inspection (LBI) uses a narrow pulse, high peak power, large diameter laser beam to createstress waves in the structure. These strong mechanical waves can create a tension load on theadhesive bond. If the bond is weak, the joint will fail at the test point. This failure can bedetected by sensors in the laser bond inspection device (LBID) or by post test NDI such asultrasound. While these stress wave methods are not strictly nondestructive, when they areperformed at a proof testing energy level they are nondestructive to strong bonds but destructiveto weak bonds. Recent developments in LBI testing have resulted in successful testing oncalibrated bond strength standards and on CFRP to metal bonds. A system suitable for factoryimplementation has been developed.