Abstract
A RECENT paper by Pearson1 reports the results of crack propagation experiments on various metals, of which Young's moduli E range from 6.5 × 106 lb./in.2 to 30 × 106 lb./in.2. It was found that the fatigue crack propagation rates were sensibly equal when the applied stress f was a fixed proportion of E. I have recently obtained theoretical support for this from the (static) analysis of the stresses in the neighbourhood of a crack in a perfectly elastic sheet. Account is taken of the varying geometry of the crack and it is shown, for example, that near the tip of the crack where x is measured from the tip and in line with the crack, 2c is the length of the crack, and σy the direct stress normal to the line of the crack. The important points to notice from this equation are that the stresses are not proportional to the applied load and, furthermore, they depend on the value of Young's modulus itself. A measure of the extent of the stress singularity is given by equating to unity the terms in parentheses, whence The significance of the parameter follows immediately from the assumption that the crack propagation rate depends primarily on the distance x̄.
Similar content being viewed by others
Article PDF
References
Pearson, S., Nature, 211, 1077 (1966).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
MANSFIELD, E. Fatigue Crack Propagation in Metals. Nature 213, 277 (1967). https://doi.org/10.1038/213277b0
Received:
Issue Date:
DOI: https://doi.org/10.1038/213277b0
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.