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Optical strain based pre-failure indication in failure process of geomaterials
Sudipta Bhattacharjee1, Debasis Deb2
1Advanced Technology Development Center, IIT Kharagpur, 721302 India.
Scientific Reports
|April 22, 2016
Summary
A new indicator accurately detects microcrack development and yielding in geomaterials by analyzing cumulative effective strain. This method, using multilevel extended digital image correlation (X-DIC) and finite element method (FEM), aids in understanding material behavior under stress.
Area of Science:
- Geotechnical Engineering
- Materials Science
- Computational Mechanics
Background:
- Accurate measurement of geomaterial deformation under uniaxial loading is crucial for understanding their mechanical behavior.
- Existing methods may lack the precision to identify subtle changes like microcrack initiation and yielding.
- The finite element method (FEM) and digital image correlation (DIC) are powerful tools for analyzing material deformation.
Purpose of the Study:
- To develop and validate a novel indicator for detecting the onset of microcrack development and yielding in geomaterials.
- To apply a multilevel extended digital image correlation (X-DIC) technique integrated with FEM for precise deformation measurement.
- To explore the relationship between cumulative effective strain, volumetric strain, and material failure mechanisms.
Main Methods:
- Utilized a multilevel extended digital image correlation (X-DIC) technique combined with the finite element method (FEM).
- Incorporated Smooth Particle Hydrodynamics (SPH) for displacement smoothing and strain tensor calculation at FEM nodal points.
- Estimated cumulative effective strain from strain tensors to analyze stress-strain behavior and identify failure precursors.
Main Results:
- Cumulative effective strain effectively identifies changes in stress-strain behavior of geomaterials.
- The developed indicator, linked to cumulative effective strain and volumetric strains, accurately predicts the onset of microcrack development and yielding.
- Experimental validation with concrete and rock samples demonstrated the indicator's potential in identifying material failure and dilation.
Conclusions:
- The developed indicator provides a reliable method for assessing the critical states of microcracking and yielding in geomaterials.
- The integration of X-DIC, FEM, and SPH offers a robust framework for advanced geomaterial analysis.
- The findings contribute to improved safety and design methodologies in geotechnical engineering and materials science.
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