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Updated: Apr 15, 2026
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Crack Monitoring in Resonance Fatigue Testing of Welded Specimens Using Digital Image Correlation
Published on: September 29, 2019
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Digital imaging of crack evolution in granite containing unparallel flaws under fatigue loading
Vahid Kordloo1, Kamran Goshtasbi1, Hamid Reza Nejati2
1Department of Rock Mechanics, School of Engineering, Tarbiat Modares University, Tehran, Iran.
Scientific Reports
|April 13, 2026
Summary
Flaw geometry significantly impacts crack propagation and failure patterns in jointed rock masses under monotonic and cyclic loading. Overlapping flaws alter crack coalescence, while cyclic loading introduces unique crack behaviors and influences mechanical properties.
Area of Science:
- Rock Mechanics
- Geotechnical Engineering
- Materials Science
Background:
- Jointed rock mass failure is a critical issue in civil and mining engineering.
- Understanding crack initiation, propagation, and coalescence is key to designing safer rock structures.
Purpose of the Study:
- Investigate the influence of flaw geometry and loading conditions (monotonic vs. cyclic) on granite's crack propagation and mechanical properties.
- Analyze crack development and failure patterns under varied unparallel flaw orientations.
Main Methods:
- Utilized Digital Image Correlation (DIC) for high-resolution monitoring of crack development.
- Tested five distinct flaw geometries under monotonic and cyclic compressive loading.
- Varied cyclic stress amplitudes at 75%, 80%, and 85% of peak strength.
Main Results:
- Flaw geometry dictates crack coalescence paths and failure modes, shifting from indirect to direct trajectories with overlapping flaws.
- Cyclic loading can alter crack paths and create unique 'cyclic cracks', distinct from monotonic failure.
- Overlapping geometries (S90, S45) showed higher strength and crack initiation stress ratios under monotonic loading.
Conclusions:
- Flaw geometry is a primary factor controlling crack coalescence and failure mechanisms in jointed rocks.
- Cyclic loading introduces unique crack behaviors and influences mechanical properties differently than monotonic loading.
- Fatigue life is governed by flaw geometry and loading amplitude, with some geometries exhibiting non-linear responses.
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