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Distorting crack-front geometry for enhanced toughness by manipulating bioinspired heterogeneity
Kaijin Wu1, Zhaoqiang Song2, Mengqi Liu1
1CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei, Anhui, China.
Nature Communications
|January 2, 2025
Summary
Controlling crack propagation in heterogeneous materials is key to enhancing toughness. This study reveals a bioinspired mechanism where anisotropic heterogeneities create helical crack fronts, significantly boosting fracture resistance.
Area of Science:
- Materials Science
- Fracture Mechanics
- Bioinspired Engineering
Background:
- Controlling crack propagation is essential for developing tougher heterogeneous materials.
- The toughening mechanisms of rough, tortuous cracks in heterogeneous materials are not well understood, unlike smooth cracks in homogeneous materials.
Purpose of the Study:
- To investigate a distorted crack-front geometric toughening mechanism using bioinspired anisotropic heterogeneities.
- To understand how microstructural orientations and component properties influence crack behavior and fracture resistance.
Main Methods:
- Theoretical analysis and experimental demonstration of crack propagation in heterogeneous systems.
- Utilizing bioinspired twisted plywood structures to create anisotropic heterogeneities.
- Investigating crack front distortion under remote mode I loading.
Main Results:
- Local mixed-mode fracture (I+II+III) triggered by anisotropic heterogeneities leads to a helical crack front.
- An anomalous nonlinear relationship between fracture resistance, helical crack-front length, and microstructural orientation was observed.
- A design protocol for toughness amplification by engineering crack front helicity was developed.
Conclusions:
- Provides physical insights into how biological heterogeneities modulate tortuous crack fronts.
- Offers a benchmark solution for enhancing material toughness through parametric engineering of spatial heterogeneities.
- Highlights the importance of 3D crack front topography in toughening mechanisms.
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