EVALUATION OF FATIGUE DAMAGE ACCUMULATION BY ACOUSTIC-EMISSION

Improvements in acoustic emission (AE) test techniques have lead to de velopments whereby reliable acoustic emission measurements as a fatigu e damage indicator were made at room temperature on Incoloy 901 smooth specimens, over a stress-ratio range of - 1.0 less than or equal to R less than or equal to 0.2. Fatigue damage accumulation was evaluated in terms of an AE damage definition and a damage function was develope d. Thus, various damage phases in the cumulative damage process were i dentified by their AE signature, and then formulated and analyzed in t erms of cumulative AE ringdown counts.