A TEST METHOD TO MEASURE THE EFFECTS OF RESIDUAL STRESS DURING AN FCG TEST
Residual stress in material can pose significant challenges during material characterization, especially during fatigue crack growth testing at relatively low values of applied DK, where even modest amounts of residual stress can bias the crack growth rate data. This paper discusses a recent test method that can be used during standard compliance-based fatigue crack growth testing to measure the stress-intensity factor, Kres, caused by the residual stress in a test specimen. This data can then be used to partition residual stress effects from the fatigue crack growth data, a necessary step to understand true material performance before introducing residual stress formally into the structural design process. Positive results have motivated an effort to standardize the method as a non-mandatory appendix in ASTM E647.