ISO 17561:2002

INTERNATIONAL ISO
STANDARD 17561
First edition
2002-03-01


Fine ceramics (advanced ceramics,
advanced technical ceramics) — Test
method for elastic moduli of monolithic
ceramics at room temperature by sonic
resonance
Céramiques techniques — Méthode d'essai des modules d'élasticité des
céramiques monolithiques, à température ambiante, par résonance
acoustique




Reference number
ISO 17561:2002(E)
©
ISO 2002

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ISO 17561:2002(E)
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ISO 17561:2002(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
The main task of technical committees is to prepare International Standards. Draft International Standards adopted
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Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 17561 was prepared by Technical Committee ISO/TC 206, Fine ceramics.

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INTERNATIONAL STANDARD ISO 17561:2002(E)

Fine ceramics (advanced ceramics, advanced technical
ceramics) — Test method for elastic moduli of monolithic
ceramics at room temperature by sonic resonance
1 Scope
This International Standard describes the method of test for determining the dynamic elastic moduli of fine
ceramics at room temperature by sonic resonance. This International Standard is for fine ceramics that are elastic,
homogeneous and isotropic.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 3611, Micrometer callipers for external measurement
ISO 6906, Vernier callipers reading to 0,02 mm
3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
3.1
dynamic elastic moduli
adiabatic elastic moduli, which are dynamic Young's modulus, shear modulus and Poisson's ratio
NOTE Adiabatic elastic moduli are obtained by the sonic resonance method.
3.1.1
Young's modulus (E)
elastic modulus in tension or compression
E = σ / ε
where
E is Young's modulus in pascals;
σ is the tension or compression stress in pascals;
ε is the tension or compression strain.
3.1.2
shear modulus (G)
elastic modulus in shear or torsion
G = τ /γ
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ISO 17561:2002(E)
where
G is the shear modulus in pascals;
τ is the shear or torsional stress in pascals;
γ is the shear or torsional strain.
3.1.3
Poisson's ratio (ν)
ratio of transverse strain to the corresponding axial strain resulting from uniformly distributed axial stress below the
proportional limit of the material
NOTE In isotropic materials, Young's modulus (E), shear modulus (G) and Poisson's ratio (ν) are related by the following
equation:
ν=−EG/(2 ) 1
3.2
Vibrations
3.2.1
flexural vibrations
those vibrations apparent when the oscillation in a slender bar is in plane normal to the length dimension
NOTE Also defined as vibrations in a flexural mode.
3.2.2
torsional vibrations
those vibrations apparent when the oscillation in each cross-section plane of a slender bar is such that the plane
twists around the length dimension axis
NOTE Also defined as vibrations in a torsional mode.
3.3
resonance
the state if, when a slender bar driven into one of the above modes of vibration, the imposed frequency is such that
the resultant displacements for a given amount of driving force are at a maximum
NOTE The resonant frequencies are natural vibration frequencies which are determined by the elastic modulus, mass and
dimensions of the test piece.
4 Summary of test method
This test method measures the flexural or torsional frequencies of test specimens of rectangular prism or cylindrical
geometry by exciting them at continuously variable frequencies. Mechanical excitation of the specimens is provided
through the use of a transducer that transforms a cyclic electrical signal into a cyclic mechanical force on the test
piece. A second transducer senses the resulting mechanical vibrations of the test piece and transforms them into
an electrical signal. The amplitude and the frequency of the signal are measured by an oscilloscope or other means
to detect resonance. The peak response is obtained at the resonant frequency. The fundamental resonant
frequencies, dimensions and mass of the specimen are used to calculate the dynamic elastic moduli. The Young's
modulus is determined from the flexural resonance frequency, and the shear modulus is determined from the
torsional resonance frequency, together with the test piece dimensions and mass. Poisson's ratio is determined
from the Young's modulus and the shear modulus.
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ISO 17561:2002(E)
5 Apparatus
5.1 General
There are various techniques that may be used to determine the resonant frequency of the test piece. The test
piece may be excited by direct mechanical contact of a vibrator, or it may be suspended by a wire from a vibrator. It
may be driven electromagnetically by attaching thin foils of magnetic material to one surface, or electrostatically by
attaching an electrode to one surface.
One example of the test apparatus is shown in Figure 1. The driving circuit consists of an oscillator, an amplifier, a
driver and a frequency counter. The detecting circuit consists of a detector, an amplifier and an oscilloscope.
Figure 1 shows the suspension style of the apparatus. The direct contact support style of the test apparatus, shown
in Figure 2, is also possible. It consists of a variable-frequency audio oscillator, used to generate a sinusoidal
voltage, and a power amplifier and suitable transducer to convert the electrical signal to a mechanical driving
vibration. A frequency meter (preferably digital) monitors the audio oscillator output to provide accurate frequency
determination. A suitable suspension coupling system supports the test piece. A transducer detector acts to detect
mechanical vibration in the specimen and to convert it into an electrical signal which is passed through an amplifier
and displayed on an indicating meter. The meter may be a voltmeter, a microammeter or an oscilloscope. An
oscilloscope is recommended because it enables the operator to positively identify resonances, including higher
order harmonics, by Lissajous figure analysis. If a Lissajous figure is desired, the output of the oscillator is also
coupled to the horizontal plates of the oscilloscope.

Key
1 Frequency counter
2 Oscillator
3 Amplifier
4 Driver
5 Oscilloscope
6 Detector
7 Suspending string
Figure 1 — Example of the test apparatus and the suspension for fundamental flexural resonance
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ISO 17561:2002(E)

Key
1 Driving
2 Detecting
3 Flexural
Figure 2 — Example of the direct contact support of the test piece for fundamental flexural resonance
5.2 Oscillator
The oscillator shall be able to vary the frequency from 100 Hz to 20 kHz, with a frequency resolution of 1 Hz and a
maximum frequency drift of 1 Hz/min.
5.3 Amplifier
The audio amplifier shall have a power output sufficient to ensure that the type of transducer used can excite any
specimen the mass of which falls within a specified range. A power amplifier in the detector circuit shall be
impedance-matched with the type of detector transducer selected and shall serve as a prescope amplifier.
5.4 Driver
The driver shall be able to convert electrical vibration to mechanical vibration. The frequency response of the driver
transducer across the frequency range of interest shall have at least a 6,5 kHz bandwidth before − 3 dB power loss
occurs.
NOTE For flexibility in testing, the bandwidth can, with advantage, be at least as large as the frequency range given in Table 1.
5.5 Detector
The detector shall generate a voltage proportional to the amplitude, velocity or acceleration of the mechanical
vibration of the specimen. The frequency response of the detector across the frequency range of interest shall have
at least a 6.5 kHz bandwidth before a − 3 dB power loss occurs.
NOTE For flexibility in testing, the bandwidth can, with advantage, be at least as large as the frequency
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