Effect of Ripple Load on Stress-Corrosion Cracking in Structural Steels
Abstract
The presence of small ripple loading can, under certain circumstances, significantly reduce time to failure and threshold stress intensity of stress corrosion cracking (SCC) of steels. A predictive framework for such ripple-loading effects (RLE) is developed from concepts and descriptors used in SCC and corrosion fatigue characterization. The proposed framework is capable of defining critical conditions required for the occurrence of RLE and predicting time-to-failure curves. The agreement between the predicted and laboratory data is excellent. SCC is a cracking process caused by the conjoint action of stress and corrodent. Conceptually, SCC will occur if a sensitive material is exposed to a corrosive environment under sufficient stress for a sufficient length of time. For a structural material which contains a crack or crack-like defect, the resistance to SCC is normally evaluated in terms of the fracture mechanics parameter, the threshold stress-intensity factor below which crack extension will not occur. Applications in the real world, however - including many in offshore platform structures, rarely involve an absolutely constant load condition, but involve the superposition of relatively small amplitude load perturbations or ripple loads.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1991
- Accession Number
- ADA235730
Entities
People
- P. S. Pao
- R. A. Bayles
Organizations
- United States Naval Research Laboratory