Threshold Fatigue Crack Growth Behavior
Final rept. Aug 1985-Jul 1988
PRATT AND WHITNEY WEST PALM BEACH FL GOVERNMENT ENGINE BUSINESS
Pagination or Media Count:
This constitutes the Final Report for Air Force Contract F33615-85-C-5050. Threshold Fatigue Crack Growth Behavior. The sponsoring agency was the Materials Laboratory, Wright Research Development Center, Wright-Patterson Air Force Base, Dayton, Ohio. The period of performance was 1 August 1985 through 31 July 1988. The objective of the program was to develop and demonstrate a methodology for predicting the high cycle fatigue HCF life of a gas turbine engine blade alloy containing defects of either intrinsic or extrinsic origin using threshold fracture mechanics concepts. The program centered around experimental measurements of threshold stress intensity delta for Ti 8Al-1Mo-1V and the assessment of influencing factors such as frequency, stress ratio, and temperature. The uniqueness of K sub th as well as the effects of time-dependent crack growth behavior were also investigated. Finally, an attempt was made to model HCF behavior based on fracture mechanics principles and the delta K sub th data base. Keywords Threshold crack growth Fracture mechanics High cycle fatigue Fatigue.