SEDL / STP / STP1060-EB / STP23439S

Some Special Computations and Experiments on Surface Crack Growth

Prodan, M
Leader of group, Fracture and Damage Mechanics, Sulzer Bros., Ltd., Winterthur,

Radon, JC
Honorary research fellow, Imperial College of Science and Technology, London,

Pages: 16    Published: Jan 1990

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Abstract

The new method of surface crack growth calculation under linear elastic fracture mechanics (LEFM) conditions facilitates the use of stress-intensity factor K (and in particular its ΔK range) as a tool to estimate the fatigue life of cracked plates under tensile loads. This is made possible by determining a set of parameters in order to obtain equal ΔK values and analogous crack propagation rates in two widely different specimen geometries, a plate and a standard compact type (C(T)) specimen. A comparison of fatigue lives with equivalent crack growth for both types of specimen suggests that in using the proposed procedure, the significance of ΔK values in a part-through crack is closely related to that of a through crack in a C(T) specimen.

In analyzing the surface crack growth under elastic-plastic conditions, it should be necessary to use J values in a different way than in LEFM. Appropriate references to both problems are quoted.