Evaluation of New Bonding Systems for Depot-Level Maintenance of Aircraft Honeycomb Panels.

摘要

Four adhesive systems, EA 9628, ADX 656.2, PL 717B, and M1113, are evaluated and reported to be improvements over adhesives presently used for bonding honeycomb structures in army helicopters. These systems have increased durability and fatigue properties but do not change the stiffness of the panel. Using corrosion-in-hibiting primers can increase the life expectancy of the structure provided the application of the primer is very stringently controlled. An investigation into fracture analysis of failed joints indicates that the origin of failure, the mechanism of crack propagation, and an estimate of the load the joint experienced at the time of failure can be detected by a careful analysis of the joint. A nondestructive technique by which the degradation in a bonded panel can be followed using the Harmonic Bond Tester has been evaluated. The technique detects changes in the adhesive, the onset of corrosion in the bond line, and the presence of voids. (Author)