Journal Published Online: 04 August 2020
Volume 9, Issue 5

Characterization of Intrinsic to Support Crack Growth Estimates under Spectrum Loading in the HCF/VHCF Domain



Closure-free intrinsic threshold stress intensity, ΔKth,i, can vary significantly depending on near-tip residual stress, σ*. σ* is a computed parameter that is sensitive to hysteretic stress–strain crack-tip response to applied load history. The test procedure developed in earlier work to characterize ΔKth,i as a function of σ* was optimized and validated on three different materials, demonstrating both consistent estimates of ΔKth,i as well as its unique relationship with σ*. A detailed description of the improved test procedure is provided to enable implementation on a target test system. Establishment of the ΔKth,i versus σ* relationship permits improved estimates of extended duration spectrum load fatigue crack growth associated with high cycle fatigue (HCF) and very high cycle fatigue (VHCF). The test procedure to characterize this relationship merits adoption as a standard test practice given the promise of bridging a longstanding gap between laboratory test techniques and requirements of residual crack growth life estimates under long-duration spectrum loading.

Author Information

Sunder, R.
BISS Division, ITW India Private Ltd., Bangalore, India
Koraddi, Ramesh
BISS Division, ITW India Private Ltd., Bangalore, India
Chandra, Vishwas
Ramaiah University of Applied Sciences, Bangalore, India
Pages: 19
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Stock #: MPC20190223
ISSN: 2379-1365
DOI: 10.1520/MPC20190223