Volume 1, Issue 8 (September 2004)
Crack Growth and Closure Behavior of Short and Long Fatigue Cracks under Random Loading
Crack growth and closure behavior of physically short and conventionally long cracks under random loading are extensively investigated, utilizing test results of 2024-T351 aluminum alloy obtained by performing narrow- and wide-band random loading tests for various stress ratios and random loading block lengths. A noise reduction method is developed to determine the crack opening load under random loading more easily, precisely, and economically. Crack growth rates are analyzed mainly in terms of the stress intensity factor range estimated by 2/PI correction proposed by Donald and Paris. The long and short cracks are very different in characteristics of closure behavior under random loading. Crack growth of short and long cracks under random loading can be well described by the crack closure concept. The effects of random spectrum or random block length on crack opening load and crack growth are not significant.