SIST EN ISO 18610:2021

SLOVENSKI STANDARD
oSIST prEN ISO 18610:2020
01-oktober-2020
Fina keramika (sodobna keramika, sodobna tehnična keramika) - Mehanske
lastnosti keramičnih kompozitov pri temperaturi okolice in pri zračnem tlaku -
Ugotavljanje elastičnih lastnosti z ultrazvokom (ISO 18610:2016)
Fine ceramics (advanced ceramics, advanced technical ceramics) - Mechanical
properties of ceramic composites at ambient temperature in air atmospheric pressure -
Determination of elastic properties by ultrasonic technique (ISO 18610:2016)
Hochleistungskeramik - Mechanische Eigenschaften von keramischen
Verbundwerkstoffen bei Raumtemperatur - Bestimmung der elastischen Eigenschaften
durch eine Ultraschallmethode (ISO 18610:2016)
Céramiques techniques (céramiques avancées, céramiques techniques avancées) -
Propriétés mécaniques des céramiques composites à température ambiante sous air à
pression atmosphérique - Détermination des propriétés élastiques par méthode
ultrasonore (ISO 18610:2016)
Ta slovenski standard je istoveten z: prEN ISO 18610
ICS:
81.060.30 Sodobna keramika Advanced ceramics
oSIST prEN ISO 18610:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 18610:2020

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oSIST prEN ISO 18610:2020
INTERNATIONAL ISO
STANDARD 18610
First edition
2016-09-15
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Mechanical properties of ceramic
composites at ambient temperature
in air atmospheric pressure —
Determination of elastic properties by
ultrasonic technique
Céramiques techniques (céramiques avancées, céramiques techniques
avancées) — Propriétés mécaniques des céramiques composites
à température ambiante sous air à pression atmosphérique —
Détermination des propriétés élastiques par méthode ultrasonore
Reference number
ISO 18610:2016(E)
©
ISO 2016

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oSIST prEN ISO 18610:2020
ISO 18610:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
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Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

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oSIST prEN ISO 18610:2020
ISO 18610:2016(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 5
5 Significance and use . 6
6 Test equipment. 7
6.1 Immersion tank with temperature measurement device . 7
6.2 Holder of the probes and test object . 7
6.3 Probes . 7
6.4 Pulse generator . 7
6.5 Signal display and recording system . 7
7 Test object . 7
8 Test object preparation . 8
9 Test procedure . 8
9.1 Choice of frequency . 8
9.2 Establishment of the test temperature . 9
9.3 Reference test without test object . 9
9.4 Measurement with the test object . 9
9.4.1 Determination of the bulk density and thickness . 9
9.4.2 Mounting of the test object . 9
9.4.3 Acquisition of different angles of incidence . 9
10 Calculation .10
10.1 Delay .10
10.2 Calculation of the propagation velocities .10
10.3 Calculation of the refracted angle, θ .10
r
10.4 Identification of the elastic constants, C .10
ij
10.4.1 Basic considerations .10
10.4.2 Calculation of C .12
33
10.4.3 Calculation of C , C and C .12
22 23 44
10.4.4 Calculation of C , C and C .12
11 13 55
10.4.5 Calculation of C and C .12
12 66
10.5 Polar plots of the velocity curves .13
10.6 Calculation of the quadratic deviation and the confidence interval .14
10.7 Calculation of the engineering constants .14
11 Test validity .15
11.1 Measurements .15
11.2 Criterion of validity for the reliability of the C components .15
ij
12 Test report .15
Annex A (informative) Example of a presentation of the results for a material with
orthotropic symmetry .17
Bibliography .19
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oSIST prEN ISO 18610:2020
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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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 206, Fine ceramics.
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oSIST prEN ISO 18610:2020
INTERNATIONAL STANDARD ISO 18610:2016(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Mechanical properties of ceramic composites
at ambient temperature in air atmospheric pressure
— Determination of elastic properties by ultrasonic
technique
1 Scope
This document specifies an ultrasonic method to determine the components of the elasticity tensor of
ceramic matrix composite materials at room temperature. Young’s moduli shear moduli and Poisson
coefficients, can be determined from the components of the elasticity tensor.
This document applies to ceramic matrix composites with a continuous fibre reinforcement:
unidirectional (1D), bidirectional (2D), and tridirectional (×D, with 2 < × ≤ 3) which have at least
orthotropic symmetry, and whose material symmetry axes are known.
This method is applicable only when the ultrasonic wavelength used is larger than the thickness of
the representative elementary volume, thus imposing an upper limit to the frequency range of the
transducers used.
NOTE Properties obtained by this method might not be comparable with moduli obtained by ISO 15733,
ISO 20504 and EN 12289.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3611, Geometrical product specifications (GPS) — Dimensional measuring equipment: Micrometers for
external measurements — Design and metrological characteristics
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
EN 1389, Advanced technical ceramics — Ceramic composites — Physical properties — Determination of
density and apparent porosity
3 Terms and definitions
For the purposes of this document, the terms and definitions given in CEN/TR 13233 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
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3.1
stress-strain relations for orthotropic material
elastic anisotropic behaviour of a solid homogeneous body described by the elasticity tensor of fourth
order C , represented in the contracted notation by a symmetrical square matrix (6 × 6)
ijkl
Note 1 to entry: If the material has at least orthotropic symmetry, its elastic behaviour is fully characterized
by nine independent stiffness components C , of the stiffness matrix (C ), which relates stresses to strains, or
ij ij
equivalently by nine independent compliance components S of the compliance matrix (S ), which relates strains
ij ij
to stresses. The stiffness and compliance matrices are the inverse of each other.
If the reference coordinate system is chosen along the axes of symmetry, the stiffness matrix C and the
ij
compliance matrix S can be written as follows:
ij
     
σ C C C 00 0 ε
1 11 12 13 1
     
σ CC C 000 εε
     
2 12 22 23 2
     
σ C CC 000 ε
3 113 23 33 3
     
=
σ 000 C 00 ε
     
4 44 4
     
σ 000 00C ε
5 55 5
     
σ  000 00 C  ε 
6 66 6
     
     
ε SS S 00 0 σ
1 11 12 13 1
     
ε SS S 000 σσ
  
2 12 22 23  2
     
ε S SS 000 σ
3 113 23 33 3
     
=
ε 000 S 00 σ
     
4 44 4
     
ε 000 00S σ
5 55 5
     
ε  000 00 S  σ 
6 66 6
     
Note 2 to entry: For symmetries of higher level than the orthotropic symmetry, the C and S matrices have the
ij ij
same form as here above. Only the number of independent components reduces.
3.2
engineering constants
compliance matrix components of an orthotropic material which are in terms of engineering constants:
 
−ν −ν
121 31
00 0
 
EE
E
11 33
22
 
−ν −ν
12 1 32
 00 0 
EE
E
11 33
 
22
−ν
−νν
 
13 23 1
00 0
 E 
 
E E
S =
22
ij 11 33
 
 
1
00 0 00
 
G
23
 
1
00 00 0
 
G
13
 
1
00 00 0
 
G
 12
where
E , E and E are the elastic moduli in directions 1, 2 and 3, respectively;
11 22 33
G , G and G are the shear moduli in the corresponding planes;
12 13 23
ν , ν , ν are the respective Poisson coefficients.
12 13 23
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3.3
angle of incidence
θ
i
angle between the direction 3 normal to the test specimen front face and the direction n of the
i
incident wave
Note 1 to entry: See Figures 1 and 2.
3.4
refracted angle
θ
r
angle between the direction 3 normal to the test specimen front face and the direction n of propagation
of the wave inside the test specimen
Note 1 to entry: See Figures 1 and 2.
3.5
azimuthal angle
ψ
angle between the plane of incidence (3, n ) and plane (2, 3) where n corresponds to the vector oriented
i i
along the incident plane wave and direction 2 corresponds to one of the axes of symmetry of the
material
Note 1 to entry: See Figure 1.
r
n
Figure 1 — Definition of angles
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h

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i
r
n
n
i
i
Figure 2 — Propagation in the plane of incidence
3.6
first critical angle
θ
c
angle of incidence θ that provides an angle of refraction of 90 degrees of the quasi longitudinal wave angle
i
3.7
unit vector
n
vector of length 1 oriented along the propagation direction of the incident plane wave inside the
specimen, with its components n (k = 1, 2, 3):
k
n =sinsθψin
1 r
n =sincθψos
2 r
n =cosθ
3 r
Note 1 to entry: See Figures 1 and 2.
3.8
propagation velocity
V(n)
phase velocity of a plane wave inside the specimen in dependence on unit vector n (i.e. in dependence
on ψ and θ )
r
Note 1 to entry: V is the propagation velocity in the coupling fluid.
o
3.9
delay
δt(n)
difference between the time-of-flight of the wave when the test specimen is in place and the time-of-
flight of the wave in the coupling fluid with the test specimen removed under the same configuration of
the probes in dependence on unit vector n
3.10
bulk density
ρ
ratio of the mass of the material without porosity to its total volume including porosity
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oSIST prEN ISO 18610:2020
ISO 18610:2016(E)

4 Principle
The determination of the elastic properties consists of calculating the coefficients of the propagation
equation of an elastic plane wave, from a set of properly chosen velocity measurements along known
directions.
A thin specimen with plane parallel faces is immersed in an acoustically coupling fluid (e.g. water),
see Figure 3. The specimen is placed between a transmitter (T) and a receiver (R), which are rigidly
connected to each other and have two rotational degrees of freedom. Using appropriate signal
processing, the propagation velocities of each wave in the specimen are calculated.
θ i
Key
1 rotation drive
2 test object
3 pulse generator
4 digital oscilloscope
5 micro-computer
Figure 3 — Ultrasonic test assembly
Depending on the angle of incidence, the wave created by the pulse sent by the transmitter T is refracted
within the material in one (a quasi longitudinal wave QL, or a quasi transverse wave QT), two (QL+ QT or
two quasi transverse waves QT , QT ) or three bulk waves (QL+ QT +QT ) that propagate in the solid at
1 2 1 2
different velocities and in different directions.
The receiver R collects one, two or three pulses, corresponding to each of these waves.
The difference between the time-of-flight of each of the waves and the time-of-flight of the transmitted
pulse in the coupling fluid without the test object is measured. The evaluation procedure is based on
the measurement of the time-of-flight of the quasi-longitudinal and one or both quasi-transverse waves,
and is only valid when the QL and the QT waves are appropriately separated (see Figure 4).
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05 10 15 20 25
θ
Key Key
Y  amplitude Y  amplitude
X  angle of incidence X  time
NOTE  Both QL and QT waves are present and can
be distinguished in the positive domain but are
slightly overlapping in the negative domain.
a) Amplitude of the QL and QT waves as a b) Temporal waveform of the QL and QT waves
function of the angle of incidence with at an angle of incidence, θ , close to the critical
i
overlapping in the region of θ angle, θ
c c
Figure 4 — Example of partial overlapping of QL and QT waves at an angle of incidence θ
i
From the propagation velocities, the components of the elasticity tensor are obtained through a least
square regression analysis which minimizes the residuals of the wave propagation equations.
Young’s moduli, shear moduli and Poisson coefficients are determined from these components.
5 Significance and use
Only two constants (Lamés coefficients, Young’s modulus and Poisson coefficient, Young’s and shear
moduli, longitudinal and transverse wave velocities) are sufficient in order to fully describe the
elastic behaviour of an isotropic solid body. When anisotropy, which is a specific feature of composite
materials, shall be taken into account, the use of an elasticity tensor with a larger number of independent
coefficients is needed. While conventional mechanical methods allow only a partial identification of
the elasticity of anisotropic bodies, ultrasonic techniques allow a more exhaustive evaluation of the
elastic properties of these materials, particularly transverse elastic moduli and shear moduli for thin
specimens.
Successful application of the method depends critically on an appropriate selection of the central
frequency of the transducers. Frequency shall be sufficiently low for the measurement to be
representative of the elementary volume response, but at the same time high enough to achieve a
separation between the QL and the QT waves.
The determination of elastic properties by the ultrasonic technique described here is based on a non-
destructive dynamic measurement of wave propagation velocities. The determination of the values of
Young’s moduli, shear moduli and Poisson ratios need a single specimen.
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oSIST prEN ISO 18610:2020
ISO 18610:2016(E)

6 Test equipment
6.1 Immersion tank with temperature measurement device
The temperature of the coupling fluid in the immersion tank should stay constant within ±0,5 °C for the
full duration of the test.
The temperature measurement device shall be capable of measuring the temperature to within 0,5 °C.
This requirement is imposed because the wave propagation velocity in the coupling fluid is temperature
sensitive.
6.2 Holder of the probes and test object
The holder of the ultrasonic probes or the holder of the test object shall allow a rotation to cover the
range of angles of incidence θ between 0° and 90°. Additionally, it shall allow for discrete settings of the
i
azimuthal angle ± of 0°, 45° and 90°. The accuracy in the measurement of the angles θ and ψ shall be
i
better than 0,1° and 1°, respectively.
The probes shall be mounted in such a way that their relative position remains fixed during the test.
6.3 Probes
Piezoelectric broad-band probes adapted to the coupling fluid and able to generate longitudinal
ultrasonic waves shall be used. Two probes with similar specifications (e.g. central frequency,
bandwidth) shall be used as transmitter and receiver.
6.4 Pulse generator
The pulse generator shall be selected in accordance with the characteristics of the probes.
It shall be able to generate short-duration (<1 µs) sinusoidal pulses of voltage sufficient to provide a
mechanical pulse by the transducer. The frequency of the exciting pulse shall be chosen, such as
described in 9.1.
The interval between consecutive pulses shall be long compared with the travel time being recorded,
typically greater than 1 ms, so that all signals from the preceding pulse have dissipated before initiating
the next.
6.5 Signal display and recording system
Use any system, for instance, e.g. digital oscilloscope, with a minimum sampling frequency of 100 MHz
that allows the recording of transmitted and received signals. The signal recording system is designed
in order to allow one to see on the display the generated and the detected pulses on the same time-base
and to determine the time-gap separating these two events.
7 Test object
The choice of the geometry of the test object depends on the nature of the material and the
reinforcement structure. The thickness shall be large enough to allow separation of the echoes of the
quasi longitudinal QL and quasi transverse QT waves and shall be representative of the material. The
largest possible thickness is recommended, at least five times the size of the representative volume
element (RVE) in the direction of propagation of the wave. The other dimensions of the test object shall
be at least twice the diameter of the transducer. A test object with parallel faces is mandatory. The two
faces shall be parallel of better than 0,1 mm.
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oSIST prEN ISO 18610:2020
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8 Test object preparation
The material symmetry axes shall be identified. If machining is required, it shall be performed in such a
way that the material symmetry axes remain known at all times.
Machining procedures that do not cause damage to the test objects shall be clearly defined and recorded.
These procedures shall be followed during machining of the test objects.
NOTE Usually, test objects from plates are cut with their longitudinal axis coinciding with one of the
principal directions of the reinforcement.
One test object is sufficient to perform the test. Multiple measurements can be done on a single test object.
Care shall be taken to avoid chemical interaction between the coupling fluid and the test object.
9 Test procedure
9.1 Choice of frequency
The selection of the appropriate frequency is critical for the application of the method. The frequency
shall be sufficiently low to ensure that the measurement is representative.
V
NOTE 1 An initial selection of f < 02, , where d is the characteristic length of the RVE in the direction of
d
normal incidence, is proposed (θ = 0).
i
Where d is the characteristic length of the RVE in the direction of normal incidence (θ = 0) and V the
i
propagation velocity inside the specimen and in that direction, is proposed.
V
NOTE 2 Because of the inverse relationship between wavelength λ and frequency f ( f = ), this corresponds
λ
to a wavelength λ of at least 5d.
For the selected frequency, the following additional criteria should be met:
a) measurable amplitude of the QL wave under normal incidence θ = 0. If the amplitude is too small,
i
the frequency shall be decreased;
b) time separation of the waves QL and QT when varying the angle of incidence θ [see Figure 4 b)].
i
This is promoted by increasing the frequency.
3V
A minimum frequency of is recommended.
2h
Because the frequency requirements for meeting the three mentioned criteria may be conflicting, there
are cases where the method is not applicable. In these cases, the only remaining solution is to increase
the thickness of the test object beyond the minimum thickness stipulated in Clause 7.
NOTE 3 For example, for a 2D SiC/SiC with a RVE of 0,5 mm (requiring a minimum thickness of the test object
of 2,5 mm in accordance with Clause 7), the test frequency, in order for the measurement to be representative, is
lower than 2,25 MHz (corresponding to wave velocities of around 5 000 m/s). On the other hand, for obtaining
3V
mode separation, the frequency is higher than = 3MHz . The method can therefore not be applied for the
2h
given thickness of 2,5 mm. An increase in thickness to 3,3 mm allows mode separation at a frequency of 2,25 MHz.
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9.2 Establishment of the test temperature
Measure the temperature of the coupling fluid at a location between the transducers in the vicinity of
the future position of the test specimen. Perform the reference measurement in accordance with 9.3.
Perform the test in accordance with 9.4.
9.3 Reference test without test object
Record the signals from the transmitter and from the receiver versus time without a test object
mounted.
9.4 Measurement with the test object
9.4.1 Determinatio
...