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Controlled Strain of 3D Hydrogels under Live Microscopy Imaging
Published on: December 4, 2020
Magic angles and cross-hatching instability in hydrogel fracture
T Baumberger1, C Caroli, D Martina
1INSP, UPMC Université Paris 06, CNRS UMR 7588, 140 rue de Lourmel, 75015 Paris, France.
Physical Review Letters
|June 4, 2008
Summary
Fracture analysis in gelatin reveals unique crack propagation behavior. Cracks exhibit strong anisotropy and a cross-hatched pattern below a critical velocity due to instabilities.
Area of Science:
- Materials Science
- Rheology
- Fracture Mechanics
Background:
- Understanding fracture mechanics in soft solids like gelatin is crucial for material design.
- Quasistatic crack propagation in gels exhibits complex surface roughness.
- Anisotropy and instabilities in fracture are not fully understood in these materials.
Purpose of the Study:
- To analyze the 2D roughness profiles of fracture surfaces in gelatin gels.
- To characterize the anisotropy and instabilities during crack propagation.
- To investigate the relationship between crack behavior and material properties.
Main Methods:
- 2D analysis of fracture surface roughness profiles.
- Observation of quasistatic crack propagation in gelatin gels.
- Identification of crack velocities and resulting surface patterns.
Main Results:
- Observed strong anisotropy in roughness profiles, independent of velocity.
- Identified a subcritical instability below a critical velocity, forming a cross-hatched regime.
- Macrostep drift at specific angles and nucleation on crack-pinning inhomogeneities were noted.
- Step height correlated with the strain-hardened zone width.
Conclusions:
- Gelatin fracture surfaces exhibit unique anisotropic behavior.
- A critical velocity governs the transition to a cross-hatched fracture regime.
- Material properties like elastic crack blunting influence fracture characteristics in soft solids.
