Evolutionary Analysis of Heterogeneous Granite Microcracks Based on Digital Image Processing in Grain-Block Model
Guanlin Liu1, Youliang Chen1, Xi Du1
1Department of Civil Engineering, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China.
Materials (Basel, Switzerland)
|March 10, 2022
Summary
Microstructure heterogeneity in rocks causes stress concentrations, leading to microcracks and failure. Numerical models reveal crack initiation at grain boundaries and varying crack patterns in quartz, feldspar, and biotite under compression.
Area of Science:
- Rock mechanics
- Computational geosciences
- Materials science
Background:
- Rock microstructure heterogeneity significantly influences microcrack evolution during compression.
- Understanding grain-scale damage mechanisms is crucial for predicting rock failure.
Purpose of the Study:
- To investigate the damage mechanism and microcrack characteristics of heterogeneous Biotite granite under compression.
- To develop and validate a numerical model for simulating rock fracture at the grain scale.
Main Methods:
- Digital image processing techniques to construct a digital image-based heterogeneous grain model.
- Discrete element method (DEM) to simulate compression and fracture.
- Model calibration against laboratory macroscopic properties of biotite granite.
Main Results:
- Microcracking initiates at weak grain boundaries; intragranular shear cracks indicate peak strength.
- Microstructure heterogeneity causes stress concentration, essential for crack initiation and rupture.
- Crack patterns vary across mineral types (quartz, feldspar, biotite), influenced by confining pressure.
Conclusions:
- Numerical simulations accurately replicate experimental observations of microcrack propagation and damage modes.
- Microstructure heterogeneity is a primary driver of rock fracture complexity.
- Confining pressure alters failure modes from tensile splitting to shear failure.
Related Concept Videos
01:20Microcracking in Concrete
227
Microcracking in concrete refers to the tiny cracks that can form within the material even before any external load is applied. These microcracks typically occur at the interface between the coarse aggregate and the hydrated cement paste, often as a result of differential volume changes prompted by variations in stress-strain behavior, as well as thermal and moisture movement. Initially, these microcracks remain stable and do not grow substantially until the concrete is stressed to about 30...
227
02:18X-ray Crystallography
24.4K
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
24.4K
01:10X-ray Diffraction of Biological Samples
4.1K
X-ray diffraction or XRD is an analytical tool that utilizes X-rays to study ordered structures such as crystalline organic and inorganic samples, polycrystalline materials, proteins, carbohydrates, and drugs.
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal...
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal...
4.1K