Cyclic analysis of propagating short cracks at notches and short-crack growth behaviour

✍ Scribed by J.C. Wang; Y.Z. Lu

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 1018 KB
• Volume: 34
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(89)90220-8

✦ Synopsis

Elastic-plastic and large-strain finite element analyses of propagating short cracks at notches under cyclic loading and the corresponding fatigue crack growths of short cracks have been studied. The specimens used in both numerical analyses and crack growth testing were semicircular notched and V-shaped notched flat panels with a through-thickness short crack emanating from the notch root. In the analyses, the cracks were assumed to propagate sequentially with an incremental length of an element sire at the maximum load of cyclic loading. Plastic zones, stress fields and strain fields around the crack tips as well as crack-closure and crack-opening stresses at different crack lengths were given. It was found that the minimum crack growth rate, obtained by fatigue testing, occurred at the crack length at which the crack-closure stress was the highest. The cyclic J-integral was then computed at different crack lengths by the finite element method and exhibits path dependence. The value of the cyclic J-integral with the path near the crack tip is larger than that with the path away from the crack tip and both are less than the value obtained by Dowling's approach. Finally correlation among the fatigue crack growth rate, cyclic J-integral and the results of cyclic analyses of propagating short cracks at notches was discussed