Accession Number:

AD0603406

Title:

SIZE EFFECTS ON FATIGUE CRACK PROPAGATION,

Descriptive Note:

Corporate Author:

CALIFORNIA INST OF TECH PASADENA FIRESTONE FLIGHT SCIENCES LAB

Personal Author(s):

Report Date:

1964-04-01

Pagination or Media Count:

51.0

Abstract:

The expressions for crack propagation rate as proposed by various investigators were closely examined. In particular, the discrepancy between Weibulls constant propagation rate formula and the behavior dldN 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 authors 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

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE