ACCOUNTING FOR RESIDUAL STRESS IN FATIGUE CRACK GROWTH RATE TESTS: VALIDATION OF RESIDUAL STRESS INTENSITY FACTOR MEASUREMENTS

Fatigue crack growth rate (FCGR) test data are a key to ensuring structural safety by design and inspection, but residual stress in test specimens can lead to significant (and unknown) bias in FCGR data. In turn, biased FCGR data confound estimates of structural capability for fielded systems. The paper will describe an experimental method for measuring the residual stress intensity factor as a function of crack size, Kres(a), during FCGR tests and provide data for validation. Further test data show that simultaneous measurements of FCGR and Kres(a) enable residual stress bias to be removed from FCGR test data.
EXTENDED ABSTRACT