Plasticity and Roughness Closure Interactions Near the Fatigue Crack Growth Threshold
Author | : RS. Piascik |
Publisher | : |
Total Pages | : 14 |
Release | : 2003 |
ISBN-10 | : OCLC:1251645422 |
ISBN-13 | : |
Rating | : 4/5 (22 Downloads) |
Download or read book Plasticity and Roughness Closure Interactions Near the Fatigue Crack Growth Threshold written by RS. Piascik and published by . This book was released on 2003 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced model has been developed to calculate interactions between plasticity and roughness closure mechanisms resulting in the fatigue crack growth threshold. Near-threshold closure is complex because multiple closure mechanisms are likely, including roughness-, oxide-, and plasticity-induced crack closure. Results show closure first occurs either at the crack tip (tip contact), or at the fatigue-crack-surface asperity nearest the crack tip (asperity contact), in the absence of load history effects. Model calculations, verified by laboratory experiments, reveal a transition from tip contact to asperity contact produces fatigue crack growth threshold behavior; here, both model and experiment show that an abrupt increase in closure (asperity contact) results in the rapid decrease in fatigue crack growth rate at threshold. A comparison of an advanced crack-tip load displacement measurement technique, and standard global compliance methods show that global methods lack the sensitivity to accurately characterize crack closure at threshold.