Negative R-ratio crack closure effects on Fatigue Crack Growth (FCG) are defined as the contribution of the compressive portion of the stress cycle to the crack extension, in addition to that contributed from the tensile portion of the cycle. Any potential decrease in FCG may be attributed to the mechanical effects of crack closure during the compressive part of the cycle. The overall effect is to decrease the crack opening portion of the stress range and to therefore reduce the crack growth rate compared to that obtained using the full stress range. This paper provides a brief overview of the treatment of negative R-ratio crack closure in FCG calculations on stainless steel components by reference to existing codes and standards. Then, using the results from crack closure tests on small cylindrical test specimens, a set of guidelines for the treatment of crack closure in the FCG assessment of stainless steel components are provided.

This content is only available via PDF.
You do not currently have access to this content.