Anomalous aspects of crack closure

✍ Scribed by R. S. Vecchio

• Book ID: 104615077
• Publisher: Springer Netherlands
• Year: 1986
• Tongue: English
• Weight: 300 KB
• Volume: 31
• Category: Article
• ISSN: 1573-2673
• DOI: 10.1007/bf00018922

✦ Synopsis

Conventional fatigue crack propagation (FCP) testing reveals a strong dependence of crack growth rate (da/dN) on the stress intensity factor range (AK) that often assumes a sigmoidal relationshi p . At low values of ilK, the rapid decrease in crack growth rates associated with decreasing £K levels is believed to be related to a significant decrease in the effective crack driving force that results from a pronounced increase in the level of crack tip closure.

Numerous investigators [1] have noted that the level of crack closure increases markedly in the fatigue threshold regime and that this increase in closure may be related to localized deflection of the crack out of the nominal crack plane and/or crack surface interference associated with the presence of asperities on the fracture surface.