SYMPOSIA PAPER Published: 01 January 1988

The Significance of Sliding Mode Crack Closure on Mode III Fatigue Crack Growth


During Mode III loading, the surfaces of a crack move parallel to each other; friction, abrasion, and mutual support of the contacting parts of the microscopically rough crack faces result. These energy-dissipative processes reduce the effective load at the crack tip, a phenomenon known as “sliding mode crack closure” (SMCC). This effect has been studied by performing crack growth experiments on circumferentially notched specimens of high-strength (AISI 4340) and mild steel (AISI C1018) under pure cyclic torsion and under combined loading (cyclic Mode III + static Mode I). Crack growth rates without the influence of sliding mode crack closure (“true” crack growth rates) can be determined using an extrapolation procedure. These crack growth rates are independent of crack depth, specimen diameter, and loading level and are therefore a material characteristic for Mode III fatigue crack growth. With the aid of the “true” crack growth curve the extent of sliding mode crack closure can be quantitatively determined and the changes in fracture mode explained. By superimposing a static tensile load the sliding mode crack closure is reduced whereas the “true” crack growth rates are only slightly influenced.

Author Information

Tschegg, EK
Technical University, Vienna, Austria
Stanzl, SE
University of Vienna, Vienna, Austria
Price: $25.00
Contact Sales
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Developed by Committee: E08
Pages: 214–232
DOI: 10.1520/STP23218S
ISBN-EB: 978-0-8031-5034-8
ISBN-13: 978-0-8031-0925-4