SIZE EFFECTS ON FATIGUE CRACK PROPAGATION,
Abstract
The expressions for crack propagation rate as proposed by various investigators were closely examined. In particular, the discrepancy between Weibull's constant propagation rate formula and the behavior dl/dN = Cl, is reconciled by the overall geometric effect in a finite plate. Furthermore, the strain concentration due to localized necking accounts for the difference from formulas recommended by Paris and Erdogen, and McEvily and Boettner. The experimental results of Frost and Dugdale are also compared with the author's previous results. A physical model for fatigue fracture mode transition based on the thickness effect has been proposed. The calculated points of transition in comparison with the experimental results indicate a consistent pattern as suggested by the proposed model. A concept for non-propagating crack is suggested. The suggested physical model is equivalent to G sub c for fatigue crack propagation. A detailed discussion on the size of plastic zone and its stress concentration is given in the Appendix. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1964
- Accession Number
- AD0603406
Entities
People
- H. W. Liu
Organizations
- California Institute of Technology