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Simple apparatus for measuring the dynamic shear modulus of cylindrical specimens
1Department of Physics, Wright State University, Dayton, Ohio 45435Department of Geology, Wright State University, Dayton, Ohio 45435.
The Review of Scientific Instruments
|April 1, 1979
Summary
This study presents a new apparatus for measuring the shear modulus of cylindrical materials using torsional vibrations. The system offers high frequency stability and automatic tracking for accurate material property determination.
Area of Science:
- Materials Science
- Mechanical Engineering
- Physics
Background:
- Accurate determination of material properties like shear modulus is crucial for engineering applications.
- Traditional methods for measuring shear modulus can be complex and time-consuming.
Purpose of the Study:
- To describe a novel apparatus for determining the shear modulus of cylindrical specimens.
- To highlight the apparatus's capabilities in self-excited torsional vibrations.
Main Methods:
- Utilized an eddy-current driver and pickup system for specimen excitation and detection.
- Employed a feedback circuit with a phase-locked-loop and amplitude control for stable vibration.
- Measured shear modulus through torsional mode vibrations of cylindrical specimens.
Main Results:
- Achieved a frequency stability of 1 part in 10^6 for high-Q materials.
- Demonstrated automatic tracking of frequency changes up to a few percent with minimal error.
- Successfully determined the shear modulus of cylindrical specimens in the audio frequency range.
Conclusions:
- The developed apparatus provides a stable and accurate method for measuring shear modulus.
- The system's automatic tracking capabilities enhance its utility for dynamic material analysis.
- This apparatus is suitable for characterizing high-Q materials in torsional vibration.
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