This project addresses the durability of adhesive bonds against failure due to fatigue in the ultra-long life region of over 10 million cycles. An accelerated testing method will be used based on piezoelectric ceramic actuators which can supply large strain/stress actuation at frequencies up to 50,000 Hz. Complications such as heat generation due to the rapid cycling and frequency dependent failure behavior will be examined experimentally and theoretically. Fatigue damage mechanisms and damage evolution processes in the adhesive joints under different mechanical loading and environmental conditions will be systematically investigated. Micro-mechanial models of damage mechanisms will be developed and integrated with continuum mechanics calculations to predict the structural durability of adhesive joints under cyclic loading.
