ASTM C623 sets a standard method for determining the elastic properties of glass and glass-ceramic materials by resonance. The test aims to determine the natural resonant frequencies of the specimen, and analysts calculate the elastic constants from the measured resonance frequencies, specimen dimensions, and density or mass as applicable. The standard:
- Calculates Young’s modulus, shear modulus, and Poisson’s ratio.
- Applies the impulse excitation (resonance) method of non-destructive testing.
- Measures the resonant frequency in flexural and torsional modes.
- Supports high-temperature testing if necessary.
- Accurately and repeatably characterizes materials for quality control.
- ASTM C623 covers suitable glass and glass-ceramic materials that are elastic, homogeneous, and isotropic and can be prepared in suitable specimen geometries.Â
What are the Uses of ASTM C623 Test Standard?
Glass manufacturers, research laboratories, and testing laboratories use ASTM C623 to evaluate the elastic properties of glass and glass-ceramic materials with minimal stress applied to the specimen. Engineers use the results to assess material stiffness, support product design, and evaluate whether glass products meet applicable engineering and performance requirements. Common applications include:
- Measurement of elastic properties of glass and glass-ceramics.
- Measurement of Young’s Modulus, Shear Modulus, and Poisson’s Ratio.
- Assisting in the quality control process in glass production.
- Assessment of structural glass for use in architecture.
- Characterization of suitable glass and glass-ceramic materials for material development and evaluation.
- Evaluation of electronic components and glass-ceramic substrates.
- Helping develop new types of glass.
- Optimizing material selection for high-temperature applications.Â
What is Resonance Testing in ASTM C623?
Analysts use resonance testing to determine a material’s elastic properties from its natural vibration frequencies. The laboratory excites the glass specimen and analyzes its resonance frequencies to determine Young’s modulus, shear modulus, and Poisson’s ratio.
Why is Resonance Testing Important for Glass and Glass-Ceramics?
Glass and glass-ceramics are brittle substances that require special testing methods other than conventional tensile tests to assess them without causing damage. Laboratories can evaluate their elastic properties using resonance testing without applying the larger stresses associated with conventional static loading methods. These measurements can be used to help predict the behavior of the structure, assess the vibration performance of the structure, check for thermal stresses, and enhance the reliability of the product.
How Does ASTM C623 Measure Elastic Properties?
Technicians suspend the prepared specimen using a suitable support arrangement specified by ASTM C623. The test apparatus mechanically excites the specimen and produces vibrations that allow the laboratory to identify resonance frequencies. The measurement system detects the specimen’s mechanical vibrations and identifies the flexural and torsional resonance frequencies using the applicable resonance-measurement system. The frequencies, along with the dimensions and mass of the specimen, are used to determine Young’s modulus, shear modulus, and Poisson’s ratio in accordance with ASTM C623.
Common Challenges and Troubleshooting
Improper dimensions, improper support positioning, poor impoundment, environmental vibrations, inaccurate mass or dimension measurements, and improperly calibrated measuring equipment are some of the factors that may affect the accuracy of ASTM C623 measurements. To improve repeatability and reliability, technicians should prepare specimens with uniform geometry, accurately measure their dimensions, locate the appropriate support points, calibrate the instrumentation, and minimize external vibration during testing.
