Effect of Multiaxial Loading on Crack Growth. Volume 1. Technical Summary
Abstract
An exploratory research program has been conducted to systematically evaluate the effects of biaxial stress ratio on constant amplitude and variable amplitude fatigue crack growth rates. A series of experiments and analyses have been carried out on the cyclic crack growth behavior of center-cracked cruciform specimens under various biaxial loading conditions. The results may be summarized as follows. Crack will grow straight in a biaxial stress field when the stress component parallel to the crack is equal to or smaller than the stress component normal to the crack. Elastic K factors are obtainable for both straight and curved cracks and are adequate for correlating the biaxial growth rate data. At a given stress intensity level, the constant amplitude crack growth rates are the same in all the biaxial loading conditions. In out-of-phase loading conditions, the crack growth rate and crack growth directions are the same as those in the in-phase loading conditions. Crack tip plastic zone size variations with biaxial ratio appeared to have no effect on constant-amplitude crack growth rate. As for the variable amplitude tests, it is very evident that cracks grow faster at positive biaxial stress states, but slower at negative biaxial loading conditions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1978
- Accession Number
- ADA072122
Entities
People
- A. F. Liu
- D. F. Ditmer