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Dynamic Compressive and Tensile Characterisation of Igneous Rocks Using Split-Hopkinson Pressure Bar and Digital
Albin Wessling1, Jörgen Kajberg1
1Division of Solid Materials, Luleå University of Technology, 97187 Luleå, Sweden.
Materials (Basel, Switzerland)
|November 26, 2022
Summary
This study details rock fracture mechanics using Split-Hopkinson Pressure Bar and high-speed imaging. It reveals fracture initiation points and overloading effects in granite and diorite, crucial for geothermal drilling.
Area of Science:
- Geophysics and Geomechanics
- Materials Science and Engineering
Background:
- Understanding dynamic rock fracture is vital for industrial applications like geothermal energy extraction.
- Accurate numerical simulations require precise knowledge of dynamic mechanical properties and crack behavior.
Purpose of the Study:
- To dynamically characterize the mechanical properties of Kuru grey granite and Kuru black diorite.
- To investigate fracture initiation and propagation using advanced imaging and analysis techniques.
Main Methods:
- Utilized Split-Hopkinson Pressure Bar (SHPB) tests complemented by high-speed imaging (671,000 fps).
- Performed Brazilian disc and uniaxial compression tests, incorporating Digital Image Correlation (DIC) for the Brazilian disc test.
- Employed a novel methodology combining high-speed imaging and DIC to evaluate overloading effects.
Main Results:
- Fracture initiation in compression tests occurred at 93-95% of peak dynamic strength for granite and diorite.
- Overloading effects in the Brazilian disc test were quantified at 30% for granite and 23% for diorite.
- High-speed imaging and DIC provided reliable estimates of crack formation and propagation.
Conclusions:
- The combined use of SHPB, high-speed imaging, and DIC offers a robust method for rock dynamic fracture characterization.
- Accurate tensile strain evaluation is achievable with appropriate sensing region selection and high temporal resolution.
- Findings contribute to improved numerical modeling for rock fracture in engineering applications.
Keywords:
Split-Hopkinson pressure bardigital image correlationdynamic mechanical propertiesfracturehigh-speed imagingrockMore Related Videos
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