ASTM C848-88(2006)
(Test Method)Standard Test Method for Young's Modulus, Shear Modulus, and Poisson's Ratio For Ceramic Whitewares by Resonance
Standard Test Method for Young's Modulus, Shear Modulus, and Poisson's Ratio For Ceramic Whitewares by Resonance
SIGNIFICANCE AND USE
This test system has advantages in certain respects over the use of static loading systems in the measurement of ceramic whitewares.
3.1.1 Only minute stresses are applied to the specimen, thus minimizing the possibility of fracture.
3.1.2 The period of time during which stress is applied and removed is of the order of hundreds of microseconds, making it feasible to perform measurements at temperatures where delayed elastic and creep effects proceed on a much-shortened time scale.
This test method is suitable for detecting whether a material meets specifications, if cognizance is given to one important fact: ceramic whiteware materials are sensitive to thermal history. Therefore, the thermal history of a test specimen must be known before the moduli can be considered in terms of specified values. Material specifications should include a specific thermal treatment for all test specimens.
SCOPE
1.1 This test method covers the determination of the elastic properties of ceramic whiteware materials. Specimens of these materials possess specific mechanical resonance frequencies which are defined by the elastic moduli, density, and geometry of the test specimen. Therefore the elastic properties of a material can be computed if the geometry, density, and mechanical resonance frequencies of a suitable test specimen of that material can be measured. Young's modulus is determined using the resonance frequency in the flexural mode of vibration. The shear modulus, or modulus of rigidity, is found using torsional resonance vibrations. Young's modulus and shear modulus are used to compute Poisson's ratio, the factor of lateral contraction.
1.2 All ceramic whiteware materials that are elastic, homogeneous, and isotropic may be tested by this test method. This test method is not satisfactory for specimens that have cracks or voids that represent inhomogeneities in the material; neither is it satisfactory when these materials cannot be prepared in a suitable geometry. Note 1Elastic here means that an application of stress within the elastic limit of that material making up the body being stressed will cause an instantaneous and uniform deformation, which will cease upon removal of the stress, with the body returning instantly to its original size and shape without an energy loss. Many ceramic whiteware materials conform to this definition well enough that this test is meaningful.Note 2
Isotropic means that the elastic properties are the same in all directions in the material.
1.3 A cryogenic cabinet and high-temperature furnace are described for measuring the elastic moduli as a function of temperature from 195 to 1200C.
1.4 Modification of the test for use in quality control is possible. A range of acceptable resonance frequencies is determined for a piece with a particular geometry and density. Any specimen with a frequency response falling outside this frequency range is rejected. The actual modulus of each piece need not be determined as long as the limits of the selected frequency range are known to include the resonance frequency that the piece must possess if its geometry and density are within specified tolerances.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:C848–88(Reapproved 2006)
Standard Test Method for
Young’s Modulus, Shear Modulus, and Poisson’s Ratio For
1
Ceramic Whitewares by Resonance
This standard is issued under the fixed designation C848; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.3 A cryogenic cabinet and high-temperature furnace are
described for measuring the elastic moduli as a function of
1.1 This test method covers the determination of the elastic
temperature from−195 to 1200°C.
properties of ceramic whiteware materials. Specimens of these
1.4 Modification of the test for use in quality control is
materials possess specific mechanical resonance frequencies
possible. A range of acceptable resonance frequencies is
which are defined by the elastic moduli, density, and geometry
determined for a piece with a particular geometry and density.
of the test specimen. Therefore the elastic properties of a
Any specimen with a frequency response falling outside this
material can be computed if the geometry, density, and me-
frequency range is rejected. The actual modulus of each piece
chanical resonance frequencies of a suitable test specimen of
need not be determined as long as the limits of the selected
that material can be measured.Young’s modulus is determined
frequency range are known to include the resonance frequency
using the resonance frequency in the flexural mode of vibra-
that the piece must possess if its geometry and density are
tion.The shear modulus, or modulus of rigidity, is found using
within specified tolerances.
torsional resonance vibrations. Young’s modulus and shear
1.5 This standard does not purport to address all of the
modulus are used to compute Poisson’s ratio, the factor of
safety concerns, if any, associated with its use. It is the
lateral contraction.
responsibility of the user of this standard to establish appro-
1.2 All ceramic whiteware materials that are elastic, homo-
2
priate safety and health practices and determine the applica-
geneous,andisotropicmaybetestedbythistestmethod. This
bility of regulatory limitations prior to use.
test method is not satisfactory for specimens that have cracks
or voids that represent inhomogeneities in the material; neither
2. Summary of Test Method
is it satisfactory when these materials cannot be prepared in a
2.1 This test method measures the resonance frequencies of
suitable geometry.
test bars of suitable geometry by exciting them at continuously
NOTE 1—Elastic here means that an application of stress within the
variable frequencies. Mechanical excitation of the specimen is
elastic limit of that material making up the body being stressed will cause
provided through use of a transducer that transforms an initial
aninstantaneousanduniformdeformation,whichwillceaseuponremoval
electrical signal into a mechanical vibration. Another trans-
ofthestress,withthebodyreturninginstantlytoitsoriginalsizeandshape
ducer senses the resulting mechanical vibrations of the speci-
withoutanenergyloss.Manyceramicwhitewarematerialsconformtothis
men and transforms them into an electrical signal that can be
definition well enough that this test is meaningful.
NOTE 2—Isotropic means that the elastic properties are the same in all
displayed on the screen of an oscilloscope to detect resonance.
directions in the material.
Theresonancefrequencies,thedimensions,andthemassofthe
specimen are used to calculateYoung’s modulus and the shear
modulus.
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ThistestmethodisunderthejurisdictionofASTMCommitteeC21onCeramic
Whitewares and Related Products and is the direct responsibility of Subcommittee
3. Significance and Use
C21.03 on Methods for Whitewares and Environmental Concerns.
3.1 This test system has advantages in certain respects over
Current edition approved Feb. 15, 2006. Published February 2006. Originally
approved in 1976. Last previous edition approved in 1999 as C848–88 (1999).
theuseofstaticloadingsystemsinthemeasurementofceramic
DOI: 10.1520/C0848-88R06.
whitewares.
2
Spinner, S., and Tefft, W. E., “A Method for Determining Mechanical
3.1.1 Only minute stresses are applied to the specimen, thus
Resonance Frequencies and for Calculating Elastic Moduli from These Frequen-
cies,” Proceedings, ASTM, 1961, pp. 1221–1238. minimizing the possibility of fracture.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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C848–88 (2006)
FIG. 1 Block Diagram of Apparatus
3.1.2 The period of time during which stress is applied and 4.3 Audio Amplifier, having a power output s
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