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Full-field Strain Measurements for Microstructurally Small Fatigue Crack Propagation Using Digital Image Correlation Method
Published on: January 16, 2019
Crack growth by surface diffusion in viscoelastic media.
R Spatschek1, E A Brener, D Pilipenko
1Institut für Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich, Germany.
Physical Review Letters
|December 31, 2008
Summary
This study explores steady-state crack growth, revealing distinct behaviors in Mode I and Mode III fracture mechanics. Mode III shows unstable growth transitions, while Mode I involves energy renormalization through viscous dissipation.
Area of Science:
- Solid Mechanics
- Fracture Mechanics
- Materials Science
Background:
- Crack growth is fundamental to material failure.
- Understanding steady-state crack propagation is crucial for predicting material lifespan.
- Previous models often simplify the complex dissipation mechanisms involved.
Purpose of the Study:
- To analyze steady-state crack growth as a free boundary problem.
- To differentiate the behaviors of Mode I and Mode III crack propagation.
- To investigate the influence of mixed-mode scenarios on crack velocity.
Main Methods:
- Formulation of crack growth as a free boundary problem.
- Analysis of energy dissipation mechanisms in different fracture modes.
- Comparison of crack behaviors under varying driving forces.
Main Results:
- Mode I and Mode III crack growth exhibit significantly different characteristics.
- Mode III shows a transition to unstable growth at higher driving forces.
- Mode I fracture energy is renormalized by viscous dissipation, unlike Mode III's surface dissipation dominance near the Griffith point.
- Mixed-mode scenarios enable higher steady-state crack velocities than pure Mode I.
Conclusions:
- The distinct behaviors of Mode I and Mode III crack growth necessitate tailored analytical approaches.
- Viscous dissipation plays a key role in renormalizing fracture energy in Mode I.
- Mixed-mode loading offers potential for enhanced crack growth velocities.
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