ASTM-C747 2023

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C747-23 Standard Test Method for Moduli of Elasticity and Fundamental Frequencies of Carbon and Graphite Materials by Sonic Resonance

Published By	Publication Date	Number of Pages
ASTM	2023	19

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Categories: 71.060.10 - Chemical elements, ASTM

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Description

ASTM C747-23

Active Standard: Standard Test Method for Moduli of Elasticity and Fundamental Frequencies of Carbon and Graphite Materials by Sonic Resonance

ASTM C747

Scope

1.1 This test method covers determination of the dynamic elastic properties of isotropic and near isotropic carbon and graphite materials at ambient temperatures. Specimens of these materials possess specific mechanical resonant frequencies that are determined by the elastic modulus, mass, and geometry of the test specimen. The dynamic elastic properties of a material can therefore be computed if the geometry, mass, and mechanical resonant frequencies of a suitable (rectangular or cylindrical) test specimen of that material can be measured. Dynamic Young’s modulus is determined using the resonant frequency in the flexural or longitudinal mode of vibration. The dynamic shear modulus, or modulus of rigidity, is found using torsional resonant vibrations. Dynamic Young’s modulus and dynamic shear modulus are used to compute Poisson’s ratio.

1.2 This test method determines elastic properties by measuring the fundamental resonant frequency of test specimens of suitable geometry by exciting them mechanically by a singular elastic strike with an impulse tool. Specimen supports, impulse locations, and signal pick-up points are selected to induce and measure specific modes of the transient vibrations. A transducer (for example, contact accelerometer or non-contacting microphone) senses the resulting mechanical vibrations of the specimen and transforms them into electric signals. (See Fig. 1.) The transient signals are analyzed, and the fundamental resonant frequency is isolated and measured by the signal analyzer, which provides a numerical reading that is (or is proportional to) either the frequency or the period of the specimen vibration. The appropriate fundamental resonant frequencies, dimensions, and mass of the specimen are used to calculate dynamic Young’s modulus, dynamic shear modulus, and Poisson’s ratio. Annex A1 contains an alternative approach using continuous excitation.

FIG. 1 Block Diagram of Typical Test Apparatus

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

Keywords

bar; beam; cylindrical rod; disc; dynamic; elastic modulus; elastic properties; flexure; graphite; impulse; Poisson’s ratio; resonance; resonant beam; shear modulus; torsion; Young’s modulus

GradeForming MethodSource CokeGrain Size (µm)Ash Content (wppm)Density (g/cm³)Graphite Aiso-static moldedpetroleum20<101.77Graphite Bvibration moldedcoal300<101.85 ;

ICS Code

ICS Number Code 71.060.10 (Chemical elements)

DOI: 10.1520/C0747-23

Additional information

Standard Title	C747-23 Standard Test Method for Moduli of Elasticity and Fundamental Frequencies of Carbon and Graphite Materials by Sonic Resonance
Published Code	ASTM
Publication Date	2023
Pages Count	19
ICS Codes	71.060.10 - Chemical elements