Scope:

The ASTM C1198 test method uses sonic resonance to examine the dynamic elastic properties of advanced ceramics such as dynamic young’s modulus, shear modulus, and Poisson’s ratio. This test method allows measurements to be done at high temperatures, where delayed elastic and creep effects might nullify static modulus estimations. With the awareness that the character of the reinforcement in the test specimen will have a direct effect on the elastic characteristics, this test method can be utilized to test advanced ceramics with a composite character. The ASTM C1198 test method is non-destructive in nature and can even be used on specimens that have been processed for other tests. 

Test Procedure:

ASTM C1198 test method uses a constantly varying frequency to evaluate the resonance frequencies of test specimens of proper shape. A transducer converts a cyclic electrical signal into a cyclic mechanical force on the specimen, resulting in mechanical excitation of the bars. A second transducer detects the specimen’s resulting mechanical vibrations and converts them to an electrical signal. To identify resonance, an oscilloscope or other technique is used to measure the signal’s amplitude and frequency. The dynamic Young’s modulus and dynamic shear modulus are calculated using the specimen’s resonance frequencies, size, and mass.

Specimen Size : 

Test specimens with rectangular cross-sections are preferred for ASTM C1198. Rectangular specimen dimensions are 75 mm in length, 15 mm in width, and 3 mm in thickness. 

Data:

Dynamic Young’s Modulus, Shear Modulus & Poisson’s Ratio of the ceramic specimens are reported in the SI unit and are considered as standard. Modification of the ASTM C1198 test method for use in quality control is also possible.

Conclusion:

The ASTM C1198 test method uses sonic resonance to examine the dynamic elastic properties of advanced ceramics such as dynamic young’s modulus, shear modulus, and Poisson’s ratio.