SIST EN ISO 18608:2022

Fine ceramics (advanced ceramics, advanced technical ceramics) - Mechanical properties of ceramic composites at ambient temperature in air atmospheric pressure - Determination of the resistance to crack propagation by notch sensitivity testing (ISO 18608:2017)

ISO 18608:2017 describes a method for the classification of ceramic matrix composite (CMC) materials with respect to their sensitivity to crack propagation using tensile tests on notched specimens with different notch depths. Two classes of ceramic matrix composite materials can be distinguished: materials whose strength is sensitive to the presence of notches and materials whose strength is not affected. For sensitive materials, this document defines a method for determining equivalent fracture toughness.
The parameter, Keq, is defined as the fracture toughness of a homogeneous material which presents the same sensitivity to crack propagation as the ceramic matrix composite material which is being considered. The definition of the Keq parameter offers the possibility to compare ceramic matrix composite materials with other materials with respect to sensitivity to crack propagation.
For notch insensitive materials, the concept of Keq does not apply.
ISO 18608:2017 applies to all ceramic matrix composites with a continuous fibre reinforcement, unidirectional (1 D), bidirectional (2 D), and tridirectional (x D, where 2 < x ≤ 3), loaded along one principal axis of reinforcement.

Hochleistungskeramik - Mechanische Eigenschaften von keramischen Verbundwerkstoffen bei Umgebungstemperatur in Luft unter atmosphärischem Druck - Bestimmung der Rissausbreitungsbeständigkeit durch die Kerbempfindlichkeitsprüfung (ISO 18608:2017)

Céramiques techniques - Propriétés mécaniques des céramiques composites à température ambiante sous pression atmosphérique - Détermination de la résistance à la propagation de fissure par un essai de sensibilité à l'entaille (ISO 18608:2017)

Le présent document décrit une méthode permettant de classer les matériaux composites à matrice céramique (CMC) en fonction de leur sensibilité à la propagation de fissure, à partir d'essais de traction réalisés sur des éprouvettes entaillées à différentes profondeurs. On peut distinguer deux classes de matériaux à matrice céramique: les matériaux dont la résistance présente une sensibilité à l'entaille et ceux dont la résistance n'est pas influencée par la présence d'entailles. Pour les matériaux présentant une sensibilité à l'entaille, le présent document définit une méthode de détermination de la ténacité à la rupture équivalente.
Le paramètre, Keq, est défini comme la ténacité d'un matériau homogène présentant la même sensibilité à la propagation de fissure que le matériau composite à matrice céramique étudié. Par définition, le paramètre, Keq, permet de comparer des matériaux composites à matrice céramique à d'autres matériaux, en fonction de leur sensibilité à la propagation de fissure.
Pour les matériaux qui ne sont pas sensibles à la présence d'entailles, le concept de ténacité équivalente, Keq, ne s'applique pas.
Le présent document s'applique à tous les composites à matrice céramique à renfort fibreux continu, unidirectionnel (1 D), bidirectionnel (2 D), et tridirectionnel (x D, avec 2 < x ≤ 3), sollicités suivant un axe principal de renfort.

Fina keramika (sodobna keramika, sodobna tehnična keramika) - Mehanske lastnosti keramičnih kompozitov pri temperaturi okolice in pri zračnem tlaku - Ugotavljanje odpornosti proti širjenju razpoke s preskušanjem občutljivosti zareze (ISO 18608:2017)

ISO 18608:2017 opisuje metodo za razvrščanje keramičnih matričnih kompozitnih materialov (CMC) glede na njihovo občutljivost na širjenje razpok z uporabo nateznih preskusov na zarezanih vzorcih z različnimi globinami zareze. Obstajata dva razreda kompozitnih matričnih materialov: materiali, katerih trdnost je občutljiva na prisotnost zarez, in materiali, katerih trdnost ni prizadeta. Za občutljive materiale ta dokument opredeljuje metodo za določanje enakovredne lomne žilavosti.
Parameter Keq je opredeljen kot lomna žilavost homogenega materiala, ki predstavlja enako občutljivost na širjenje razpok kot kompozitni matrični material, ki se obravnava v dokumentu. Opredelitev parametra Keq ponuja možnost primerjave kompozitnih matričnih materialov z drugimi materiali glede na občutljivost na širjenje razpok.
Za materiale, ki niso občutljivi na zareze, koncept Keq ne velja.
ISO 18608:2017 se uporablja za vse keramične matrične kompozite z neprekinjeno ojačitvijo vlaken, enosmerno (1D), dvosmerno (2D) in trismerno (xD, pri čemer je 2 < x ≤ 3), preskušenih vzdolž ene glavne osi ojačitve.

General Information

• Status: Published
• Public Enquiry End Date: 31-Jan-2022
• Publication Date: 18-Apr-2022
• ICS: 81.060.30 - Advanced ceramics
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 13-Apr-2022
• Due Date: 18-Jun-2022
• Completion Date: 19-Apr-2022
• Ref Project: EN ISO 18608:2022 - Fine ceramics (advanced ceramics, advanced technical ceramics) - Mechanical properties of ceramic composites at ambient temperature in air atmospheric pressure - Determination of the resistance to crack propagation by notch sensitivity testing (ISO 18608:2017)

Relations

• Replaces: SIST EN 13234:2007 - Advanced technical ceramics - Mechanical properties of ceramic composites at ambient temperature - Evaluation of the resistance to crack propagation by notch sensitivity testing
• Effective Date: 13-Apr-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 18608:2022
01-junij-2022
Nadomešča:
SIST EN 13234:2007
Fina keramika (sodobna keramika, sodobna tehnična keramika) - Mehanske
lastnosti keramičnih kompozitov pri temperaturi okolice in pri zračnem tlaku -
Ugotavljanje odpornosti proti širjenju razpoke s preskušanjem občutljivosti zareze
(ISO 18608:2017)
Fine ceramics (advanced ceramics, advanced technical ceramics) - Mechanical
properties of ceramic composites at ambient temperature in air atmospheric pressure -
Determination of the resistance to crack propagation by notch sensitivity testing (ISO
18608:2017)
Hochleistungskeramik - Mechanische Eigenschaften von keramischen
Verbundwerkstoffen bei Umgebungstemperatur in Luft unter atmosphärischem Druck -
Bestimmung der Rissausbreitungsbeständigkeit durch die Kerbempfindlichkeitsprüfung
(ISO 18608:2017)
Céramiques techniques - Propriétés mécaniques des céramiques composites à
température ambiante sous pression atmosphérique - Détermination de la résistance à
la propagation de fissure par un essai de sensibilité à l'entaille (ISO 18608:2017)
Ta slovenski standard je istoveten z: EN ISO 18608:2022
ICS:
81.060.30 Sodobna keramika Advanced ceramics
SIST EN ISO 18608:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 18608:2022

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SIST EN ISO 18608:2022


EN ISO 18608
EUROPEAN STANDARD

NORME EUROPÉENNE

April 2022
EUROPÄISCHE NORM
ICS 81.060.30 Supersedes EN 13234:2006
English Version

Fine ceramics (advanced ceramics, advanced technical
ceramics) - Mechanical properties of ceramic composites
at ambient temperature in air atmospheric pressure -
Determination of the resistance to crack propagation by
notch sensitivity testing (ISO 18608:2017)
Céramiques techniques - Propriétés mécaniques des Hochleistungskeramik - Mechanische Eigenschaften
céramiques composites à température ambiante sous von keramischen Verbundwerkstoffen bei
pression atmosphérique - Détermination de la Umgebungstemperatur in Luft unter atmosphärischem
résistance à la propagation de fissure par un essai de Druck - Bestimmung der
sensibilité à l'entaille (ISO 18608:2017) Rissausbreitungsbeständigkeit durch die
Kerbempfindlichkeitsprüfung (ISO 18608:2017)
This European Standard was approved by CEN on 27 March 2022.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18608:2022 E
worldwide for CEN national Members.

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SIST EN ISO 18608:2022
EN ISO 18608:2022 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 18608:2022
EN ISO 18608:2022 (E)
European foreword
The text of ISO 18608:2017 has been prepared by Technical Committee ISO/TC 206 "Fine ceramics” of
the International Organization for Standardization (ISO) and has been taken over as EN ISO 18608:2022
by Technical Committee CEN/TC 184 “Advanced technical ceramics” the secretariat of which is held by
DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2022, and conflicting national standards shall
be withdrawn at the latest by October 2022.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 13234:2006.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 18608:2017 has been approved by CEN as EN ISO 18608:2022 without any modification.

3

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SIST EN ISO 18608:2022

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SIST EN ISO 18608:2022
INTERNATIONAL ISO
STANDARD 18608
First edition
2017-03
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Mechanical properties of ceramic
composites at ambient temperature
in air atmospheric pressure —
Determination of the resistance
to crack propagation by notch
sensitivity testing
Céramiques techniques — Propriétés mécaniques des céramiques
composites à température ambiante sous pression atmosphérique
— Détermination de la résistance à la propagation de fissure par un
essai de sensibilité à l’entaille
Reference number
ISO 18608:2017(E)
©
ISO 2017

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SIST EN ISO 18608:2022
ISO 18608:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

---------------------- Page: 8 ----------------------
SIST EN ISO 18608:2022
ISO 18608:2017(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Significance and use . 2
6 Apparatus . 4
6.1 Test machine . 4
6.2 Load train. 4
6.2.1 General. 4
6.2.2 Grips . . . 4
6.2.3 Load train couplers . 4
6.3 Data recording system . 5
6.4 Micrometers . 5
6.5 Ligament size measuring device . 5
7 Specimens . 5
7.1 Un-notched test specimens . 5
7.2 Notched test specimens . 5
7.3 Notches . 6
8 Test specimen preparation . 7
8.1 Machining and preparation . 7
8.2 Number of test specimens . 7
9 Test procedure . 7
9.1 Test on reference specimen . 7
9.2 Test on notched specimen . 7
9.2.1 Displacement rate . 7
9.2.2 Measurement of test specimen dimensions . 7
9.2.3 Test technique . 7
9.2.4 Test validity . 8
10 Calculation of results . 8
10.1 Test specimen origin . 8
10.2 Tensile strength of un-notched specimen . 8
10.3 Tensile strength of the notched specimen . 8
10.4 Plotting of notch sensitivity diagram . 8
10.5 Calculation of equivalent fracture toughness for the different classes of behaviour . 9
10.5.1 Class A behaviour . 9
10.5.2 Class B behaviour . 9
10.5.3 Class C behaviour .10
11 Test report .10
Bibliography .11
© ISO 2017 – All rights reserved iii

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SIST EN ISO 18608:2022
ISO 18608:2017(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.
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 voluntary nature of standards, 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: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 206, Fine ceramics.
iv © ISO 2017 – All rights reserved

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SIST EN ISO 18608:2022
INTERNATIONAL STANDARD ISO 18608:2017(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Mechanical properties of ceramic composites
at ambient temperature in air atmospheric pressure —
Determination of the resistance to crack propagation by
notch sensitivity testing
1 Scope
This document describes a method for the classification of ceramic matrix composite (CMC) materials
with respect to their sensitivity to crack propagation using tensile tests on notched specimens with
different notch depths. Two classes of ceramic matrix composite materials can be distinguished:
materials whose strength is sensitive to the presence of notches and materials whose strength is not
affected. For sensitive materials, this document defines a method for determining equivalent fracture
toughness.
The parameter, K , is defined as the fracture toughness of a homogeneous material which presents
eq
the same sensitivity to crack propagation as the ceramic matrix composite material which is being
considered. The definition of the K parameter offers the possibility to compare ceramic matrix
eq
composite materials with other materials with respect to sensitivity to crack propagation.
For notch insensitive materials, the concept of K does not apply.
eq
This document applies to all ceramic matrix composites with a continuous fibre reinforcement,
unidirectional (1 D), bidirectional (2 D), and tridirectional (x D, where 2 < x ≤ 3), loaded along one
principal axis of reinforcement.
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 7500-1, Metallic materials — Calibration and verification of static uniaxial test
...

SLOVENSKI STANDARD
oSIST prEN ISO 18608:2022
01-januar-2022
Fina keramika (sodobna keramika, sodobna tehnična keramika) - Mehanske
lastnosti keramičnih kompozitov pri temperaturi okolice in pri zračnem tlaku -
Ugotavljanje odpornosti proti širjenju razpoke s preskušanjem občutljivosti zareze
(ISO 18608:2017)
Fine ceramics (advanced ceramics, advanced technical ceramics) - Mechanical
properties of ceramic composites at ambient temperature in air atmospheric pressure -
Determination of the resistance to crack propagation by notch sensitivity testing (ISO
18608:2017)
Hochleistungskeramik - Mechanische Eigenschaften von keramischen
Verbundwerkstoffen bei Umgebungstemperatur in Luft atmosphärischen Druck -
Bestimmung der Rissausbreitungsbeständigkeit durch die Kerbempfindlichkeitsprüfung
(ISO 18608:2017)
Céramiques techniques - Propriétés mécaniques des céramiques composites à
température ambiante sous pression atmosphérique - Détermination de la résistance à
la propagation de fissure par un essai de sensibilité à l'entaille (ISO 18608:2017)
Ta slovenski standard je istoveten z: prEN ISO 18608
ICS:
81.060.30 Sodobna keramika Advanced ceramics
oSIST prEN ISO 18608:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 18608:2022

---------------------- Page: 2 ----------------------
oSIST prEN ISO 18608:2022
INTERNATIONAL ISO
STANDARD 18608
First edition
2017-03
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Mechanical properties of ceramic
composites at ambient temperature
in air atmospheric pressure —
Determination of the resistance
to crack propagation by notch
sensitivity testing
Céramiques techniques — Propriétés mécaniques des céramiques
composites à température ambiante sous pression atmosphérique
— Détermination de la résistance à la propagation de fissure par un
essai de sensibilité à l’entaille
Reference number
ISO 18608:2017(E)
©
ISO 2017

---------------------- Page: 3 ----------------------
oSIST prEN ISO 18608:2022
ISO 18608:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

---------------------- Page: 4 ----------------------
oSIST prEN ISO 18608:2022
ISO 18608:2017(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Significance and use . 2
6 Apparatus . 4
6.1 Test machine . 4
6.2 Load train. 4
6.2.1 General. 4
6.2.2 Grips . . . 4
6.2.3 Load train couplers . 4
6.3 Data recording system . 5
6.4 Micrometers . 5
6.5 Ligament size measuring device . 5
7 Specimens . 5
7.1 Un-notched test specimens . 5
7.2 Notched test specimens . 5
7.3 Notches . 6
8 Test specimen preparation . 7
8.1 Machining and preparation . 7
8.2 Number of test specimens . 7
9 Test procedure . 7
9.1 Test on reference specimen . 7
9.2 Test on notched specimen . 7
9.2.1 Displacement rate . 7
9.2.2 Measurement of test specimen dimensions . 7
9.2.3 Test technique . 7
9.2.4 Test validity . 8
10 Calculation of results . 8
10.1 Test specimen origin . 8
10.2 Tensile strength of un-notched specimen . 8
10.3 Tensile strength of the notched specimen . 8
10.4 Plotting of notch sensitivity diagram . 8
10.5 Calculation of equivalent fracture toughness for the different classes of behaviour . 9
10.5.1 Class A behaviour . 9
10.5.2 Class B behaviour . 9
10.5.3 Class C behaviour .10
11 Test report .10
Bibliography .11
© ISO 2017 – All rights reserved iii

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oSIST prEN ISO 18608:2022
ISO 18608:2017(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.
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 voluntary nature of standards, 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: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 206, Fine ceramics.
iv © ISO 2017 – All rights reserved

---------------------- Page: 6 ----------------------
oSIST prEN ISO 18608:2022
INTERNATIONAL STANDARD ISO 18608:2017(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Mechanical properties of ceramic composites
at ambient temperature in air atmospheric pressure —
Determination of the resistance to crack propagation by
notch sensitivity testing
1 Scope
This document describes a method for the classification of ceramic matrix composite (CMC) materials
with respect to their sensitivity to crack propagation using tensile tests on notched specimens with
different notch depths. Two classes of ceramic matrix composite materials can be distinguished:
materials whose strength is sensitive to the presence of notches and materials whose strength is not
affected. For sensitive materials, this document defines a method for determining equivalent fracture
toughness.
The parameter, K , is defined as the fracture toughness of a homogeneous material which presents
eq
the same sensitivity to crack propagation as the ceramic matrix composite material which is being
considered. The definition of the K parameter offers the possibility to compare ceramic matrix
eq
composite materials with other materials with respect to sensitivity to crack propagation.
For notch insensitive materials, the concept of K does not apply.
eq
This document applies to all ceramic matrix composites with a continuous fibre reinforcement,
unidirectional (1 D), bidirectional (2 D), and tridirectional (x D, where 2 < x ≤ 3), loaded along one
principal axis of reinforcement.
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 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Calibration and verification of the force-measuring system
ISO 15733:2015, Fine ceramics (advanced ceramics, advanced technical ceramics) — Mechanical properties
of ceramic composites at ambient temperature in air atmospheric pressure — Determination of tensile
properties
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 15733 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
© ISO 2017 – All rights reserved 1

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oSIST prEN ISO 18608:2022
ISO 18608:2017(E)

3.1
ligament
part of the double edge notched specimen that is located between the notches
Note 1 to entry: The width of the ligament is denoted b; the cross-section of the ligament is denoted A.
3.2
notch depth
a
distance between the side of the specimen and the tip of the notch
3.3
notched specimen width
b
n
width of the notched specimen outside the notched cross-section
3.4
maximum tensile force
F
m
highest recorded tensile force on the test specimen when tested to failure
3.5
un-notched specimen tensile strength
σ
t,m
tensile strength determined by measurement according to ISO 15733
Note 1 to entry: The value of this parameter is designated σ .
r
3.6
notched specimen tensile strength
σ
t,m,n
ratio of the maximum tensile force to the ligament cross-section area
Note 1 to entry: The value of this parameter is designated σ .
n
3.7
equivalent fracture toughness
K
eq
fracture toughness of a homogeneous and isotropic material which presents the same dependence of
the stress ratio σ /σ on the notch depth as the investigated composite
n r
4 Principle
Tensile tests are carried out on double edge notched test specimens with notches of different depths.
The results of these tests are compared with the results of tensile tests on specimens without notches.
The cross-sectional dimensions of the notched specimens between the notches are equal to those of the
un-notched specimens.
The strength values observed on both types of specimens as a function of
...