Crack coalescence in brittle material under cyclic loading

T. Y. Ko, H. H. Einstein, John M Kemeny

Research output: Chapter in Book/Report/Conference proceedingConference contribution

13 Citations (Scopus)

Abstract

A total of 170 tests (68 tests for monotonic loading, 102 tests for cyclic loading) have been performed to investigate crack initiation, propagation and coalescence. The specimens have two pre-existing flaws which are arranged at different distances and angles. Wing cracks and secondary cracks are observed in both monotonic and cyclic tests. Wing cracks, which are tension cracks, initiate at (or near) the tips of the flaws and propagate parallel to the compressive loading axis. Secondary cracks always appear after wing crack initiation and lead to final failure. Secondary cracks initiate at the tips of the flaws and propagate in the coplanar direction of the flaw or in a horizontal (quasi-coplanar) direction. Six types of coalescence are observed. For coplanar geometry specimens, coalescence occurs due to the internal shear cracks. For non-coplanar geometry specimens, coalescence occurs through combinations of internal shear cracks, internal wing cracks and tension cracks. Contrary to monotonic tests, cyclic tests produce fatigue cracks. Fatigue cracks usually occur when 1) after coalescence, the specimens behave as if they had only one larger crack 2) specimens have been subjected to a particular number of cycles. In these experiments, two different fatigue crack initiation directions are observed: horizontal and coplanar to the flaw.

Original languageEnglish (US)
Title of host publicationProceedings of the 41st U.S. Rock Mechanics Symposium - ARMA's Golden Rocks 2006 - 50 Years of Rock Mechanics
StatePublished - 2006
Event41st U.S. Rock Mechanics Symposium - ARMA's Golden Rocks 2006 - 50 Years of Rock Mechanics - Golden, CO, United States
Duration: Jun 17 2006Jun 21 2006

Other

Other41st U.S. Rock Mechanics Symposium - ARMA's Golden Rocks 2006 - 50 Years of Rock Mechanics
CountryUnited States
CityGolden, CO
Period6/17/066/21/06

Fingerprint

brittle materials
cyclic loading
Brittleness
coalescence
Coalescence
coalescing
crack
cracks
Cracks
wings
Defects
Crack initiation
crack initiation
specimen geometry
defects
fatigue
material
Geometry
shear
fatigue tests

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

Ko, T. Y., Einstein, H. H., & Kemeny, J. M. (2006). Crack coalescence in brittle material under cyclic loading. In Proceedings of the 41st U.S. Rock Mechanics Symposium - ARMA's Golden Rocks 2006 - 50 Years of Rock Mechanics

Crack coalescence in brittle material under cyclic loading. / Ko, T. Y.; Einstein, H. H.; Kemeny, John M.

Proceedings of the 41st U.S. Rock Mechanics Symposium - ARMA's Golden Rocks 2006 - 50 Years of Rock Mechanics. 2006.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Ko, TY, Einstein, HH & Kemeny, JM 2006, Crack coalescence in brittle material under cyclic loading. in Proceedings of the 41st U.S. Rock Mechanics Symposium - ARMA's Golden Rocks 2006 - 50 Years of Rock Mechanics. 41st U.S. Rock Mechanics Symposium - ARMA's Golden Rocks 2006 - 50 Years of Rock Mechanics, Golden, CO, United States, 6/17/06.
Ko TY, Einstein HH, Kemeny JM. Crack coalescence in brittle material under cyclic loading. In Proceedings of the 41st U.S. Rock Mechanics Symposium - ARMA's Golden Rocks 2006 - 50 Years of Rock Mechanics. 2006
Ko, T. Y. ; Einstein, H. H. ; Kemeny, John M. / Crack coalescence in brittle material under cyclic loading. Proceedings of the 41st U.S. Rock Mechanics Symposium - ARMA's Golden Rocks 2006 - 50 Years of Rock Mechanics. 2006.
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