Plastics - Determination of Charpy impact properties - Part 2: Instrumented impact test (ISO 179-2:2020)

1.1 This document specifies a method for determining Charpy impact properties of plastics from
force-deflection diagrams. Different types of rod-shaped test specimens and test configurations, as well
as test parameters depending on the type of material, the type of test specimen and the type of notch, are
defined in ISO 179-1.
Dynamic effects such as load-cell/striker resonance, test specimen resonance and initial-contact/
inertia peaks are described in this document (see Figure 1, Curve b, and Annex A).
1.2 ISO 179-1 is suitable for characterizing the impact behaviour by the impact strength only and for
using apparatus whose potential energy is matched approximately to the particular energy to break
to be measured (see ISO 13802:2015, Annex E). This document is used to record a force-deflection or
force-time diagram for detailed characterization of the impact behaviour, and for developing automatic
apparatus, i.e. avoiding the need to match energy.
The method described in this document is also suitable for:
— acquiring more and different materials characteristics under impact conditions;
— supervising the Charpy test procedure, as this instrumentation allows detection of typical
operational mistakes, such as the specimen not being in close contact with the supports;
— automatically detecting the type of break;
— pendulum type instruments to avoid frequent changes of pendulum hammers;
— measuring fracture mechanical properties described in other ISO standards.
1.3 For the range of materials which can be tested by this method, see ISO 179-1:2010, Clause 1.
1.4 For the general comparability of test results, see ISO 179-1:2010, Clause 1.
1.5 Information on the typical behaviour of materials can be obtained by testing at different
temperatures, by varying the notch radius and/or specimen thickness and by testing specimens prepared
under different conditions.
It is not the purpose of this document to give an interpretation of the mechanism occurring at every
point on the force-deflection diagram. These interpretations are a task for on-going scientific research.
1.6 The test results obtained with this method are comparable only if the conditions of test specimen
preparation, as well as the test conditions, are the same. The impact behaviour of finished products
cannot, therefore, be predicted directly from this test.

Kunststoffe - Bestimmung der Charpy-Schlageigenschaften - Teil 2: Instrumentierte Schlagzähigkeitsprüfung (ISO 179-2:2020)

1.1 Dieses Dokument legt ein Verfahren zur Bestimmung der Charpy-Schlageigenschaften von Kunststoffen aus Kraft-Durchbiegungs-Diagrammen fest. In ISO 179 1 werden verschiedene Arten stabförmiger Probekörper und Prüfkonfigurationen sowie Prüfparameter in Abhängigkeit vom Werkstofftyp, Probekörpertyp und von der Kerbart festgelegt.
Dynamische Effekte, wie z. B. Resonanzen des Systems Kraftsensor/Hammerfinne, Resonanzen im Probekörper und des ersten Anschlags werden in diesem Dokument beschrieben (siehe Bild 1, Kurve b und Anhang A).
1.2 ISO 179 1 ist nur für die Charakterisierung des Schlagverhaltens durch die Schlagzähigkeit und für die Verwendung einer Prüfeinrichtung geeignet, deren potentielle Energie etwa der zu messenden Energie bis Bruch angepasst ist (siehe ISO 13802:2015, Anhang E). Dieses Dokument wird angewendet, um ein Kraft-Durchbiegungs- oder Kraft-Zeit-Diagramm für die weitergehende Charakterisierung des Schlagverhaltens aufzuzeichnen, sowie bei der Entwicklung einer automatisierten Prüfeinrichtung, bei der die Notwendigkeit der Energieanpassung vermieden werden kann.
Das in diesem Dokument beschriebene Verfahren ist auch für Folgendes geeignet:
- Ermitteln von mehr und unterschiedlichen Werkstoffeigenschaften unter Schlagbedingungen;
- Überwachen des Prüfablaufs nach Charpy, weil dieses Prüfgerät den Nachweis typischer Bedienungsfehler ermöglicht, z. B. dass der Probekörper nicht eng an den Widerlagern anliegt;
- die automatische Brucharterkennung;
- bei Pendelschlagwerken Vermeiden des häufigen Wechsels der Pendelhammer;
- Messen bruchmechanischer Eigenschaften, die in anderen ISO-Normen beschrieben sind.
1.3 Werkstoffe, die nach diesem Verfahren geprüft werden können, sind in ISO 179 1:2010, Abschnitt 1 aufgeführt.
1.4 ISO 179 1:2010, Abschnitt 1, gibt allgemeine Hinweise zur Vergleichbarkeit der Prüfergebnisse.
1.5 Informationen zum spezifischen Verhalten von Werkstoffen können durch Prüfung bei verschiedenen Prüftemperaturen, durch Änderung des Kerbgrundradius und/oder der Probekörperdicke und durch Prüfung von Probekörpern, die unter verschiedenen Bedingungen hergestellt wurden, erhalten werden.
Das Ziel dieses Dokuments ist es nicht, eine Beurteilung der auftretenden Mechanismen an jedem Punkt im Kraft-Weg-Diagramm zu geben. Das ist Aufgabe der wissenschaftlichen Forschung.
1.6 Die mit diesem Verfahren erzielten Prüfergebnisse sind nur dann vergleichbar, wenn die Bedingungen der Probekörperherstellung sowie die Prüfbedingungen gleich sind. Das Schlagverhalten von Fertigteilen kann daher aus diesen Prüfverfahren nicht direkt vorhergesagt werden.

Plastiques - Détermination des caractéristiques au choc Charpy - Partie 2: Essai de choc instrumenté (ISO 179-2:2020)

1.1 Le présent document spécifie une méthode pour la détermination des propriétés des plastiques au choc Charpy à partir de diagrammes force/flèche. L'ISO 179-1 définit différents types d'éprouvettes en forme de barreau, diverses configurations d'essai, ainsi que les paramètres d'essai à adopter suivant le type de matériau, d'éprouvette et d'entaille.
En outre, le présent document décrit les effets dynamiques, tels que la résonance de la cellule de charge/du percuteur, la résonance de l'éprouvette et les pics d'inertie au contact initial (voir la Figure 1, courbe b, et l'Annexe A).
1.2 L'ISO 179-1 est utilisable pour caractériser le comportement au choc, mais uniquement à partir de la résistance au choc et avec un appareil dont l'énergie potentielle est adaptée à l'énergie particulière à la rupture à mesurer (voir l'ISO 13802:2015, Annexe E). Le présent document est utilisé pour enregistrer un diagramme force/flèche ou force/temps pour caractériser le comportement au choc et pour mettre au point un appareillage automatique, c'est-à-dire un appareillage qui évite l'ajustement des énergies.
La méthode décrite dans le présent document convient également pour:
— acquérir davantage de caractéristiques et des caractéristiques de matériaux différents dans des conditions de choc;
— superviser le mode opératoire d'essai Charpy, car ces instruments permettent la détection d'erreurs opérationnelles type, par exemple lorsque l'éprouvette n'est pas en contact étroit avec les supports;
— détecter automatiquement le type de rupture;
— les instruments de type à pendule pour éviter des changements fréquents de marteaux;
— mesurer les propriétés mécaniques de rupture décrites dans d'autres normes ISO.
1.3 En ce qui concerne l'éventail des matériaux pouvant être soumis à l'essai au moyen de la présente méthode, voir l'ISO 179-1:2010, Article 1.
1.4 En ce qui concerne la comparabilité générale des résultats d'essai, voir l'ISO 179-1:2010, Article 1.
1.5 Des informations relatives au comportement caractéristique des matériaux peuvent être obtenues en conduisant les essais à différentes températures, en faisant varier le rayon de l'entaille et/ou l'épaisseur de l'éprouvette et en soumettant à l'essai des éprouvettes ayant été préparées dans différentes conditions.
Le présent document n'a pas pour but de donner une explication du mécanisme qui intervient à chaque point particulier du diagramme force/flèche. Ces explications sont étudiées dans le cadre des recherches scientifiques actuellement en cours.
1.6 Les résultats d'essai obtenus avec cette méthode ne sont comparables qui si les conditions de préparation des éprouvettes et les conditions d'essai retenues sont les mêmes. De ce fait, le comportement au choc des produits finis ne peut pas être directement déduit de l'essai.

Polimerni materiali - Določanje udarne žilavosti po Charpyju - 2. del: Preskus udarne žilavosti z instrumentalnim prikazom (ISO 179-2:2020)

General Information

Status
Published
Public Enquiry End Date
25-Oct-2018
Publication Date
11-Jun-2020
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
11-Jun-2020
Due Date
16-Aug-2020
Completion Date
12-Jun-2020

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SLOVENSKI STANDARD
SIST EN ISO 179-2:2020
01-september-2020
Nadomešča:
SIST EN ISO 179-2:2000
SIST EN ISO 179-2:2000/A1:2014
Polimerni materiali - Določanje udarne žilavosti po Charpyju - 2. del: Preskus
udarne žilavosti z instrumentalnim prikazom (ISO 179-2:2020)

Plastics - Determination of Charpy impact properties - Part 2: Instrumented impact test

(ISO 179-2:2020)

Kunststoffe - Bestimmung der Charpy-Schlageigenschaften - Teil 2: Instrumentierte

Schlagzähigkeitsprüfung (ISO 179-2:2020)

Plastiques - Détermination des caractéristiques au choc Charpy - Partie 2: Essai de choc

instrumenté (ISO 179-2:2020)
Ta slovenski standard je istoveten z: EN ISO 179-2:2020
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
SIST EN ISO 179-2:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 179-2:2020
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SIST EN ISO 179-2:2020
EN ISO 179-2
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2020
EUROPÄISCHE NORM
ICS 83.080.01 Supersedes EN ISO 179-2:1999
English Version
Plastics - Determination of Charpy impact properties - Part
2: Instrumented impact test (ISO 179-2:2020)

Plastiques - Détermination des caractéristiques au choc Kunststoffe - Bestimmung der Charpy-

Charpy - Partie 2: Essai de choc instrumenté (ISO 179- Schlageigenschaften - Teil 2: Instrumentierte

2:2020) Schlagzähigkeitsprüfung (ISO 179-2:2020)
This European Standard was approved by CEN on 10 May 2020.

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

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 179-2:2020 E

worldwide for CEN national Members.
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SIST EN ISO 179-2:2020
EN ISO 179-2:2020 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 179-2:2020
EN ISO 179-2:2020 (E)
European foreword

This document (EN ISO 179-2:2020) has been prepared by Technical Committee ISO/TC 61 "Plastics" in

collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by NBN.

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 December 2020, and conflicting national standards

shall be withdrawn at the latest by December 2020.

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 ISO 179-2:1999.

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 179-2:2020 has been approved by CEN as EN ISO 179-2:2020 without any modification.

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SIST EN ISO 179-2:2020
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SIST EN ISO 179-2:2020
INTERNATIONAL ISO
STANDARD 179-2
Second edition
2020-05
Plastics — Determination of Charpy
impact properties —
Part 2:
Instrumented impact test
Plastiques — Détermination des caractéristiques au choc Charpy —
Partie 2: Essai de choc instrumenté
Reference number
ISO 179-2:2020(E)
ISO 2020
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SIST EN ISO 179-2:2020
ISO 179-2:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
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SIST EN ISO 179-2:2020
ISO 179-2:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 2

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Principle ........................................................................................................................................................................................................................ 7

5 Apparatus ..................................................................................................................................................................................................................... 7

6 Test specimens.....................................................................................................................................................................................................11

7 Procedure..................................................................................................................................................................................................................11

8 Calculation and expression of results ..........................................................................................................................................12

8.1 General ........................................................................................................................................................................................................12

8.2 Calculation of deflection ..............................................................................................................................................................12

8.3 Calculation of energy ......................................................................................................................................................................13

8.4 Calculation of impact strength ...............................................................................................................................................14

8.4.1 Unnotched test specimens....................................................................................................................................14

8.4.2 Notched test specimens ..........................................................................................................................................14

8.5 Statistical parameters ....................................................................................................................................................................15

8.6 Number of significant figures ..................................................................................................................................................15

9 Precision ....................................................................................................................................................................................................................15

10 Test report ................................................................................................................................................................................................................15

Annex A (informative) Inertial peak ..................................................................................................................................................................17

Annex B (informative) Mass of frame ...............................................................................................................................................................20

Annex C (informative) Precision data ...............................................................................................................................................................21

Bibliography .............................................................................................................................................................................................................................23

© ISO 2020 – All rights reserved iii
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SIST EN ISO 179-2:2020
ISO 179-2:2020(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: www .iso .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 2,

Mechanical properties, in collaboration with the European Committee for Standardization (CEN)

Technical Committee CEN/TC 249, Plastics, in accordance with the Agreement on technical cooperation

between ISO and CEN (Vienna Agreement).

This second edition cancels and replaces the first edition (ISO 179-2:1997), which has been technically

revised. It also incorporates the Technical Corrigendum ISO 179-2:1997/Cor 1:1998 and the Amendment

ISO 179-2:1997/Amd 1:2011.
The main changes compared to the previous edition are as follows:
— references to ISO 13802:2015 have been updated;
— force calibration requirements have been clarified;

— a new subclause for the determination of test speed when using falling mass instruments has been

added (see 5.1.6).
A list of all parts of the ISO 179 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved
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SIST EN ISO 179-2:2020
INTERNATIONAL STANDARD ISO 179-2:2020(E)
Plastics — Determination of Charpy impact properties —
Part 2:
Instrumented impact test
1 Scope

1.1 This document specifies a method for determining Charpy impact properties of plastics from

force-deflection diagrams. Different types of rod-shaped test specimens and test configurations, as well

as test parameters depending on the type of material, the type of test specimen and the type of notch, are

defined in ISO 179-1.

Dynamic effects such as load-cell/striker resonance, test specimen resonance and initial-contact/

inertia peaks are described in this document (see Figure 1, Curve b, and Annex A).

1.2 ISO 179-1 is suitable for characterizing the impact behaviour by the impact strength only and for

using apparatus whose potential energy is matched approximately to the particular energy to break

to be measured (see ISO 13802:2015, Annex E). This document is used to record a force-deflection or

force-time diagram for detailed characterization of the impact behaviour, and for developing automatic

apparatus, i.e. avoiding the need to match energy.
The method described in this document is also suitable for:

— acquiring more and different materials characteristics under impact conditions;

— supervising the Charpy test procedure, as this instrumentation allows detection of typical

operational mistakes, such as the specimen not being in close contact with the supports;

— automatically detecting the type of break;
— pendulum type instruments to avoid frequent changes of pendulum hammers;
— measuring fracture mechanical properties described in other ISO standards.

1.3 For the range of materials which can be tested by this method, see ISO 179-1:2010, Clause 1.

1.4 For the general comparability of test results, see ISO 179-1:2010, Clause 1.

1.5 Information on the typical behaviour of materials can be obtained by testing at different

temperatures, by varying the notch radius and/or specimen thickness and by testing specimens prepared

under different conditions.

It is not the purpose of this document to give an interpretation of the mechanism occurring at every

point on the force-deflection diagram. These interpretations are a task for on-going scientific research.

1.6 The test results obtained with this method are comparable only if the conditions of test specimen

preparation, as well as the test conditions, are the same. The impact behaviour of finished products

cannot, therefore, be predicted directly from this test.
© ISO 2020 – All rights reserved 1
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SIST EN ISO 179-2:2020
ISO 179-2:2020(E)
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 179-1:2010, Plastics — Determination of Charpy impact properties — Part 1: Non-instrumented

impact test
ISO 291, Plastics — Standard atmospheres for conditioning and testing

ISO 2602, Statistical interpretation of test results — Estimation of the mean — Confidence interval

ISO 16012, Plastics — Determination of linear dimensions of test specimens

ISO 13802:2015, Plastics — Verification of pendulum impact-testing machines — Charpy, Izod and tensile

impact-testing
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 179-1 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
impact velocity

velocity of the striker relative to the test specimen supports at the moment of impact

Note 1 to entry: It is expressed in metres per second (m/s).
3.2
inertial peak
first peak in a force-time or force-deflection diagram

Note 1 to entry: Inertial peak arises from the inertia of that part of the test specimen accelerated after the first

contact with the striker (see Figure 1, Curve b, and Annex A).
3.3
impact force

force exerted by the striking edge on the test specimen in the direction of impact

Note 1 to entry: It is expressed in newtons (N).
2 © ISO 2020 – All rights reserved
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SIST EN ISO 179-2:2020
ISO 179-2:2020(E)
a) Force-deflection (N and C,t)
b) Force-time (C,b)
Key
X1 deflection (s) after impact in millimetres t time at break
X2 time after impact in milliseconds, ms s deflection at break
Y force (F) in newtons, N N no break, specimen pulled through
F maximum impact force C,t complete break, tough
F peak force of inertial peak C,b complete break, brittle
s deflection at maximum impact force F 1 5% of the maximum impact force
M M
s limiting deflection, beginning off pull-through
NOTE For the types of failure, see Figure 2.
Figure 1 — Typical force-deflection and force-time curves
© ISO 2020 – All rights reserved 3
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SIST EN ISO 179-2:2020
ISO 179-2:2020(E)
3.4
deflection

displacement of the striker relative to the test specimen supports after impact, starting at first contact

between striker and test specimen
Note 1 to entry: It is expressed in millimetres (mm).
3.5
impact energy

energy expended in accelerating, deforming and breaking the test specimen during the deflection (3.4)

Note 1 to entry: It is expressed in joules (J).
3.6
maximum impact force

maximum value of the impact force (3.3) in a force-time or force-deflection diagram

Note 1 to entry: See Figure 1.
Note 2 to entry: It is expressed in newtons (N).
3.7
deflection at maximum impact force
deflection (3.4) at which the maximum impact force (3.6) occurs
Note 1 to entry: See Figure 1.
Note 2 to entry: It is expressed in millimetres (mm).
3.8
energy to maximum impact force
energy expended up to the deflection at maximum impact force (3.7)
Note 1 to entry: It is expressed in joules (J).
3.9
deflection at break

deflection (3.4) at which the impact force is reduced to less than or equal to 5 % of the maximum impact

force (3.6)
Note 1 to entry: See Figure 1.
Note 2 to entry: It is expressed in millimetres (mm).
3.10
impact energy at break
impact energy (3.5) up to the deflection at break (3.9)
Note 1 to entry: It is expressed in joules (J).
4 © ISO 2020 – All rights reserved
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SIST EN ISO 179-2:2020
ISO 179-2:2020(E)
3.11
Charpy impact strength
Charpy notched impact strength
a (a )
cU cN

impact energy at break (3.10) relative to the initial central cross-sectional area A (A ) of the unnotched

(notched) specimen
Note 1 to entry: It is expressed in kilojoules per square metre (kJ/m ).
Note 2 to entry: See 8.4 and ISO 179-1:2010, 3.1 and 3.2.
3.12
type of failure

type of deformation behaviour of the material under test up to and including the breaking event

Note 1 to entry: Failure types are: complete break (3.13), hinge break (3.14), partial break (3.15), non-break (3.16).

See Figure 2.

Note 2 to entry: Types t, b and s represent subgroups of the complete break C and hinge break H defined below. For

these types, values of the impact energy at break W , and thus for the Charpy impact strength, may be averaged

to give a common mean value. For specimens giving a partial break P and for materials exhibiting interlaminar

shear fracture, see ISO 179-1:2010, 7.7. For specimens showing more than one failure type, see ISO 179-1:2010, 7.7

and ISO 179-1:2010, Clause 10 l).

Note 3 to entry: As can be seen from Figure 2, the deflection and the impact energy at maximum force are

identical to the deflection and impact energy at break in the case of splintering failure (see Curve s) and brittle

failure (see Curve b), where unstable cracking takes place at the maximum impact force.

Note 4 to entry: Usually, complete and hinge breaks cannot be differentiated in an automatic assessment based

on the force-time or force deflection-curve.
© ISO 2020 – All rights reserved 5
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SIST EN ISO 179-2:2020
ISO 179-2:2020(E)
Key
N no break (3.16) s deflection limit; beginning of pull-through
P partial break (3.15) x deflection s after impact in millimetres
C complete break (3.13) y impact force in newtons, N

NOTE 1 Due to the different modes of deformation, force-deformation curves obtained using this document

[1]

show features which are different from those obtained using ISO 6603-2 . In particular, the first damage event

in instrumented puncture tests frequently appears as a slight sudden force decrease (crack initiation), followed

by a gradual force increase. Force increases after crack initiation are never observed in instrumented three-point-

bending impact tests. Furthermore, inertial effects are not as pronounced in plate impact tests as they are in bending

impacts tests (see Annex A).

NOTE 2 The distinction between break types P and C,t is difficult. As there is some extent of unstable crack growth

in the F-s-diagram labelled C,t, the breaking behaviour was rated as less ductile than in case P when drafting the

document. Therefore, the letter “t” was used instead of “d”, which could be associated with ductile behaviour and

would better apply to break types N and P.

NOTE 3 This document can be applied to automatic testing routines. For this it is also necessary to automatically

assign the types of break by a suitable assessment of the force-time or force deflection traces observed. The table

below is an example of assessment rules that have been used successfully. Both rules are to be met for assignment.

Type of break Rule for deflection Rule for force
F(s ) c*F
L M
s ≥ s
B L
Non break
The factor c was determined experimentally
s = 31mm
and set to c = 0,3
F ≤ F(s ) ≤ c*F
0 L M
Partial break s ≥ s
B L F is the level of force at which the test is con-
sidered to be finished, e.g. F = 0,05*F
0 M
Type s: (s – s ) ≤ 1mm
B M
Type b: (s – s ) ≤ 2mm
B D
Type t: (s – s ) ≥ 2mm
B D
Complete break
s is the deflection after s ,
D M
where the steepest decline
of the F-s-curve occurs

Figure 2 — Typical force-deflection curves showing different failure modes for Type 1

specimens tested edgewise
3.13
complete break

break where the specimen separates into two or more pieces, subdivided in the following behaviours:

Note 1 to entry: See Figure 2.
3.13.1
tough break

yielding followed by stable cracking, resulting in a force at the deflection limit s which is less than or

equal to 5 % of the maximum force
3.13.2
brittle break
yielding followed by unstable cracking
6 © ISO 2020 – All rights reserved
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SIST EN ISO 179-2:2020
ISO 179-2:2020(E)
3.13.3
splintering break
unstable cracking followed by splintering
3.14
hinge break

incomplete break, such that one part of the specimen cannot support itself above the horizontal when

the other part is held vertically (less than 90° included angle)
3.15
partial break
incomplete break that does not meet the definition for a hinge or complete break

Note 1 to entry: For automatic detection resulting in a force at the deflection limit s which is greater than 5 % of

the maximum force.
3.16
non-break
yielding followed by plastic deformation up to the deflection limit, s

Note 1 to entry: The test specimen shows extended plastic deformation but no visible fracture surfaces.

4 Principle

A rod-shaped test specimen, supported near its ends as a horizontal beam, is impacted perpendicularly,

with the line of impact midway between the supports, and bent at a high, nominally constant velocity.

During the impact, the impact force is recorded as a function of time and/or deflection. Depending on

the method of evaluation, the deflection of the specimen may be either measured directly by suitable

measuring devices or, in the case of energy carriers which give a frictionless impact, calculated from

the initial velocity and the force as a function of time. The force-deflection diagram obtained in these

tests describes the high-bending-rate impact behaviour of the specimen from which several aspects of

the material properties may be inferred.
5 Apparatus
5.1 Test machine
5.1.1 Basic components

The basic components of the test machine are the energy carrier, the striker and the frame with its

specimen supports. The energy carrier may be of the inertial type (e.g. a pendulum or free-falling dart,

which may be spring- or pneumatically assisted before impact) or of the hydraulic type.

The test machine shall ensure that the specimen is bent by the impact at a nominally constant velocity

perpendicular to the specimen length. The force exerted on the specimen shall be measurable, and its

deflection in the direction of impact shall be derivable or measurable.

If the test machine is of the pendulum type it shall be verified according to ISO 13802:2015, Clause 6

and Annex A, as applicable.
5.1.2 Energy carrier

For the low-energy pendulum types specified in ISO 179-1 (see also ISO 13802:2015, Annex A), the

impact velocity, v , is (2,90 ± 0,15) m/s and for the high-energy types it is (3,8 ± 0,2) m/s. For the purposes

© ISO 2020 – All rights reserved 7
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SIST EN ISO 179-2:2020
ISO 179-2:2020(E)

of comparing impact strength data obtained using this method with data obtained in accordance with

ISO 179-1, the impact velocity used in this document shall be (2,90 ± 0,15) m/s, although it may be

desirable to also use the impact velocity v = (3,8 ± 0,2) m/s.

NOTE 1 The height of the inertial peak F (see Figure 1, Curve b), and also the amplitudes of the subsequent

vibrations of the specimen, increase with increasing impact velocity. For basic information about these vibrations,

see Annex A and References [1] and [3]. For further information about the interpretation of the inertial peak and

the damping of vibrations, see Annex A.

NOTE 2 For special applications, e.g. testing precracked test specimens to obtain data on fracture properties,

it is useful to use a lower impact velocity of, for example, 1 m/s ± 0,05 m/s to reduce the vibrations mentioned

in NOTE 1.

To avoid obtaining results which cannot be compared due to the viscoelastic behaviour of the material

under test, the decrease of velocity during impact shall not exceed 10 % if the energy carrier is rated to

less than 50 J at the speed being selected for testing. These mass carriers allow measurements between

0 % and 20 % of their nominal work capacity, E.

For the sake of extending the application range of pendulum impact instruments, in case of energy

carriers larger or equal to 50 J at the speed selected for testing, a range of 0 % to 80 % of its nominal

work capacity is permitted, this leading to a decrease of speed of 55 % in extreme cases.

The hydraulic-type energy carrier is a high-speed impact-testing machine with suitable attachments.

In the case of gravitationally accelerated energy carriers, the above impact velocities correspond to

drop heights of (43 ± 5) cm and (74 ± 7) cm, respectively, the latter representing an increase by a factor

of 1,54 in the kinetic energy E at impact if the same energy carrier is used at both impact velocities.

The maximum permitted decrease in velocity during impact specified above means that for energy

carriers smaller than 50 J the kinetic energy E in joules, at impact shall satisfy the condition given as

Formula (1):
EW/ ≥5 (1)
where W*
...

SLOVENSKI STANDARD
oSIST prEN ISO 179-2:2018
01-oktober-2018
3ROLPHUQLPDWHULDOL'RORþDQMHXGDUQHåLODYRVWLSR&KDUS\MXGHO3UHVNXV
XGDUQHåLODYRVWL]LQVWUXPHQWDOQLPSULND]RP ,62',6

Plastics - Determination of Charpy impact properties - Part 2: Instrumented impact test

(ISO/DIS 179-2:2018)

Kunststoffe - Bestimmung der Charpy-Schlageigenschaften - Teil 2: Instrumentierte

Schlagzähigkeitsprüfung (ISO/DIS 179-2:2018)

Plastiques - Détermination des caractéristiques au choc Charpy - Partie 2: Essai de choc

instrumenté (ISO/DIS 179-2:2018)
Ta slovenski standard je istoveten z: prEN ISO 179-2
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
oSIST prEN ISO 179-2:2018 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 179-2:2018
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oSIST prEN ISO 179-2:2018
DRAFT INTERNATIONAL STANDARD
ISO/DIS 179-2
ISO/TC 61/SC 2 Secretariat: KATS
Voting begins on: Voting terminates on:
2018-08-03 2018-10-26
Plastics — Determination of Charpy impact properties —
Part 2:
Instrumented impact test
Plastiques — Détermination des caractéristiques au choc Charpy —
Partie 2: Essai de choc instrumenté
ICS: 83.080.01
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 179-2:2018(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2018
---------------------- Page: 3 ----------------------
oSIST prEN ISO 179-2:2018
ISO/DIS 179-2:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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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Phone: +41 22 749 01 11
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Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
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oSIST prEN ISO 179-2:2018
ISO/DIS 179-2:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 2

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Principle ........................................................................................................................................................................................................................ 7

5 Apparatus ..................................................................................................................................................................................................................... 7

5.1 Test machine ............................................................................................................................................................................................. 7

5.1.1 Basic components ........................................................................................................................................................... 7

5.1.2 Energy carrier .................................................................................................................................................................... 7

5.1.3 Striking edge ........................................................................................................................................................................ 8

5.1.4 Pendulum ............................................................................................................................................................................... 8

5.1.5 Test specimen supports ............................................................................................................................................. 8

5.1.6 Frame ......................................................................................................................................................................................... 8

5.1.7 Losses due to friction ................................................................................................................................................... 9

5.2 Instruments for measuring force and deflection ....................................................................................................... 9

5.2.1 Force measurement ....................................................................................................................................................... 9

5.2.2 Deflection measurement ........................................................................................................................................10

5.3 Micrometers and gauges ..............................................................................................................................................................10

6 Test specimens.....................................................................................................................................................................................................10

7 Procedure..................................................................................................................................................................................................................10

8 Calculation and expression of results ..........................................................................................................................................11

8.1 General ........................................................................................................................................................................................................11

8.2 Calculation of deflection ..............................................................................................................................................................11

8.3 Calculation of energy ......................................................................................................................................................................12

8.4 Calculation of impact strength ...............................................................................................................................................12

8.4.1 Unnotched test specimens....................................................................................................................................12

8.4.2 Notched test specimens ..........................................................................................................................................13

8.5 Statistical parameters ....................................................................................................................................................................13

8.6 Number of significant figures ..................................................................................................................................................13

9 Precision ....................................................................................................................................................................................................................13

10 Test report ................................................................................................................................................................................................................13

[3]

Annex A (informative) Inertial peak ............................................................................................................................................................15

Annex B (informative) Mass of frame ...............................................................................................................................................................18

Annex C (informative) Bibliography ..................................................................................................................................................................19

Annex D (informative) Precision data ..............................................................................................................................................................20

© ISO 2018 – All rights reserved iii
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oSIST prEN ISO 179-2:2018
ISO/DIS 179-2:2018(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: www .iso .org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 2,

Mechanical properties.

ISO 179 consists of the following parts, under the general title Plastics — Determination of Charpy

impact properties:
— Part 1: Non-instrumented impact test
— Part 2: Instrumented impact test
Annexes A to C of this part of ISO 179 are for information only.
Changes made relative to ISO 179-2:1997 are:

— Amendment1: 2011 has been included into this document as “Annex D Precision Statement”.

— Minor editorial changes.

— Revision of referrals to ISO 13802 according to the currently valid edition (2015) of this standard.

— Clarification of force calibration requirements (yet missing). A relative error of 1 % throughout the

measuring range appears realistic. Discussion with manufactrueres is ongoing.
iv © ISO 2018 – All rights reserved
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oSIST prEN ISO 179-2:2018
DRAFT INTERNATIONAL STANDARD ISO/DIS 179-2:2018(E)
Plastics — Determination of Charpy impact properties —
Part 2:
Instrumented impact test
1 Scope

1.1 This part of ISO 179 specifies a method for determining Charpy impact properties of plastics from

force-deflection diagrams. Different types of rod-shaped test specimens and test configurations, as well

as test parameters depending on the type of material, the type of test specimen and the type of notch are

defined in Part 1 of ISO 179.

Dynamic effects such as load-cell/striker resonance, test specimen resonance and initial-contact/inertia

peaks are described (see Figure 1, Curve b, and Annex A).

1.2 ISO 179-1 is suitable for characterizing the impact behaviour by the impact strength only and for

using apparatus whose potential energy is matched approximately to the particular energy to break to

be measured (see ISO 13802, Annex E). This part of ISO 179 is used if a force-deflection or force-time

diagram is necessary for detailed characterization of the impact behaviour, and for developing automatic

apparatus, i.e. avoiding the need, mentioned above, to match energy.

1.3 For the range of materials which may be tested by this method, see ISO 179-1, Clause 1.

1.4 For the general comparability of test results, see ISO 179-1, Clause 1.

1.5 The method may not be used as a source of data for design calculations on components. However,

the possible use of data is not the subject of this part of ISO 179. Any application of data obtained using

this part of ISO 179 should be specified by a referring standard or agreed upon by the interested parties.

Information on the typical behaviour of materials can be obtained by testing at different temperatures,

by varying the notch radius and/or specimen thickness and by testing specimens prepared under

different conditions.

It is not the purpose of this part of ISO 179 to give an interpretation of the mechanism occurring at

every point on the force-deflection diagram. These interpretations are a task for on-going scientific

research.

1.6 The test results are comparable only if the conditions of test specimen preparation, as well as

the test conditions, are the same. Comprehensive evaluation of the reaction to impact stress requires

that determinations be made as a function of deformation rate and temperature for different material

variables such as crystallinity and moisture content. The impact behaviour of finished products cannot,

therefore, be predicted directly from this test, but test specimens may be taken from finished products

for testing by this method.

1.7 Impact strengths determined by this method may replace those determined using ISO 179-1 if

comparability has been established by previous tests.
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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 179-1, Plastics — Determination of Charpy impact properties — Part 1: Non-instrumented impact test

ISO 13802, Plastics  —  Verification  of  pendulum  impact-testing  machines  —  Charpy,  Izod  and  tensile

impact-testing
ISO 16012, Plastics — Determination of linear dimensions of test specimens

ISO 2602, Statistical interpretation of test results — Estimation of the mean — Confidence interval

3 Terms a nd definiti ons

For the purposes of this part of ISO 179, the definitions given in Part 1 apply, together with the following.

3.1
impact velocity

the velocity of the striker relative to the test specimen supports at the moment of impact

Note 1 to entry: It is expressed in metres per second (m/s).
3.2
inertial peak
the first peak in a force-time or force-deflection diagram

It arises from the inertia of that part of the test specimen accelerated after the first contact with the

striker (see Figure 1, Curve b, and Annex A).
3.3
impact force

the force exerted by the striking edge on the test specimen in the direction of impact

Note 1 to entry: It is expressed in newtons (N).
3.4
def le c t ion

the displacement of the striker relative to the test specimen supports after impact, starting at first

contact between striker and test specimen
Note 1 to entry: It is expressed in millimetres (mm).
3.5
impact energy

the energy expended in accelerating, deforming and breaking the test specimen during the deflection s

Note 1 to entry: It is expressed in joules (J).

Note 2 to entry: It is measured by integrating the area under the force-deflection curve from the point of impact

to the deflection s.
2 © ISO 2018 – All rights reserved
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oSIST prEN ISO 179-2:2018
ISO/DIS 179-2:2018(E)
3.6
maximum impact force

the maximum value of the impact force in a force-time or force-deflection diagram (see Figure 1)

Note 1 to entry: It is expressed in newtons (N).
3.7
de f le c t ion at m a x i mu m i mp ac t f or c e
the deflection at which the maximum impact force F occurs (see Figure 1)
Note 1 to entry: It is expressed in millimetres (mm).
© ISO 2018 – All rights reserved 3
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oSIST prEN ISO 179-2:2018
ISO/DIS 179-2:2018(E)

F i g u r e 1 — Ty pic a l f or c e - de f le c t ion (t op: N and t) and force-time (bottom: b) curves

(for the types of failure, see Figure 2)
4 © ISO 2018 – All rights reserved
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oSIST prEN ISO 179-2:2018
ISO/DIS 179-2:2018(E)
Key

N no break: yielding followed by plastic deformation up to the deflection limit s

P partial break: yielding followed by stable cracking, resulting in a force at the deflection limit s which is greater

than 5 % of the maximum force

t tough break: yielding followed by stable cracking, resulting in a force at the deflection limit s which is less than

or equal to 5 % of the maximum force
b brittle break: yielding followed by unstable cracking
s splintering break: unstable cracking followed by splintering
s deflection limit; beginning of pull-through

NOTE Due to the different modes of deformation, force-deformation curves obtained using this part of

[1]

ISO 179 show features which are different from those obtained using ISO 6603-2 . In particular, the first damage

event in instrumented puncture tests frequently appears as a slight sudden force decrease (crack initiation),

followed by a gradual force increase. Force increases after crack initiation are never observed in instrumented

three-point-bending impact tests. Furthermore, inertial effects are not as pronounced in plate impact tests as

they are in bending impacts tests (see Annex A).

F i g u r e 2 — Ty pic a l f or c e - de f le c t ion c u r ve s s how i n g d i f f er ent f a i lu r e mo de s f or Ty p e 1

specimens tested edgewise
3.8
energy to maximum impact force
the energy expended up to the deflection at maximum impact force
Note 1 to entry: It is expressed in joules (J).
© ISO 2018 – All rights reserved 5
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oSIST prEN ISO 179-2:2018
ISO/DIS 179-2:2018(E)
3.9
de f le c t ion at br e a k

the deflection at which the impact force is reduced to less than or equal to 5 % of the maximum impact

force F (see Figure 1)
Note 1 to entry: It is expressed in millimetres (mm).

It is necessary to differentiate between the deflection at break s and the deflection limit s at the

B L

beginning of pull-through (see Figure 1, Curve N) which is determined by the length l and width b of the

test specimen and the distance L between the specimen supports. For Type 1 specimens in the edgewise

position, s is in the range 32 mm to 34 mm.

Note 2 to entry: Using Type 1 specimens tested edgewise, apparent deflection limits are sometimes observed, i.e.

unexpectedly low values (down to only 20 mm) at which the impact force drops to zero, but the specimens do not

break. Carrying out the test slowly shows that, in such cases, the specimen changes from the edgewise to the more

stable flatwise position by a combined bending-twisting deformation. This can easily be confirmed by checking

the specimen after the test: it is bent with respect to an axis not parallel, but inclined to, the specimen width.

This behaviour is caused by the high ratio between the edgewise and the flatwise flexural rigidity of the specimen

and is triggered by a small asymmetry feature e.g. the draft angle.

The effects of such instability phenomena may be decreased by attaching guide elements to the hammer close to,

but not connected to, the instrumented striking edge. The guide elements shall allow passage of the test specimen

but be close enough together to prevent, the central part of the specimen from twisting to any great extent.

3.10
impact energy at break
the impact energy up to the deflection at break s
Note 1 to entry: It is expressed in joules (J).
3.11
charpy (notched) impact strength
a (a )
cU cN

the impact energy at break relative to the initial central cross-sectional area A (A ) of the unnotched

(notched) specimen (see 8.4 and ISO 179-1, 3.1 and 3.2)
Note 1 to entry: It is expressed in kilojoules per square metre (kJ/m ).
3.12
type of failure

the type of deformation behaviour of the material under test (see Figure 2). It may be either no

break (N), partial break (P), tough (t), brittle (b) or splintering (s)

Types t, b and s represent subgroups of the complete break C and hinge break H defined below. For

these types, values of the impact energy at break W , and thus for the Charpy impact strength, may

be averaged to give a common mean value. For specimens giving a partial break P and for materials

exhibiting interlaminar shear fracture, see ISO 179-1, 7.7. For specimens showing more than one failure

type, see ISO 179-1, 7.7 and ISO 179-1, subclause 10l).
Failure types (see ASTM D256):

C = Complete Break — A break where the specimen separates into two or more pieces.

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oSIST prEN ISO 179-2:2018
ISO/DIS 179-2:2018(E)

H = Hinge Break — An incomplete break, such that one part of the specimen cannot support itself

above the horizontal when the other part is held vertically (less than 90° included angle).

P = Partial Break — An incomplete break that does not meet the definition for a hinge break but

has fractured at least 90 % of the distance between the vertex of the notch (if present) and the

opposite side.

NB = Non-Break — An incomplete break where the fracture extends less than 90 % of the distance

between the vertex of the notch and the opposite side.

Note 1 to entry: As can be seen from Figure 2, the deflection and the impact energy at maximum force are

identical to the deflection and impact energy at break in the case of splintering failure (see Curve s) and brittle

failure (see Curve b), where unstable cracking takes place at the maximum impact force.

4 Principle

A rod-shaped test specimen, supported near its ends as a horizontal beam, is impacted perpendicularly,

with the line of impact midway between the supports, and bent at a high, nominally constant velocity.

During the impact, the impact force is recorded as a function of time and/or deflection. Depending on

the method of evaluation, the deflection of the specimen may be either measured directly by suitable

measuring devices or, in the case of energy carriers which give a frictionless impact, calculated from

the initial velocity and the force as a function of time. The force-deflection diagram obtained in these

tests describes the high-bending-rate impact behaviour of the specimen from which several aspects of

the material properties may be inferred.
5 Apparatus
5.1 Test machine
5.1.1 Basic components

The basic components of the test machine are the energy carrier, the striker and the frame with its

specimen supports. The energy carrier may be of the inertial type (e.g. a pendulum or free-falling dart,

which may be spring- or pneumatically assisted before impact) or of the hydraulic type.

The test machine shall ensure that the specimen is bent by the impact at a nominally constant velocity

perpendicular to the specimen length. The force exerted on the specimen shall be measurable, and its

deflection in the direction of impact shall be derivable or measurable.

If the test machine is of the pendulum type it shall be verified according to ISO 13802, clause 6 and

Annex A, as applicable.
5.1.2 Energy carrier

For the low-energy pendulum types specified in ISO 179-1 (see also ISO 13802, Annex A), the impact

velocity v is (2,90 ± 0,15) m/s and for the high-energy types it is (3,8 ± 0,2) m/s. For the purposes of

comparing impact strength data obtained using this method with data obtained in accordance with

ISO 179-1, the impact velocity used in this part of ISO 179 shall be (2,90 ± 0,15) m/s, although it may be

desirable to also use the impact velocity v = (3,8 ± 0,2) m/s (see also Notes 1 and 2 below).

To avoid obtaining results which cannot be compared due to the viscoelastic behaviour of the material

under test, the decrease in the velocity during impact shall not be greater than 10 % (see Note 3 below).

The hydraulic-type energy carrier is a high-speed impact-testing machine with suitable attachments.

In the case of gravitationally accelerated energy carriers, the above impact velocities correspond to

drop heights of (43± 5) cm and (74 ± 7) cm, respectively, the latter representing an increase by a factor

of 1,54 in the kinetic energy E at impact if the same energy carrier is used at both impact velocities.

© ISO 2018 – All rights reserved 7
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oSIST prEN ISO 179-2:2018
ISO/DIS 179-2:2018(E)

The maximum permitted decrease in velocity during impact of 10 % specified above means that the

kinetic energy E, in joules, at impact must satisfy the condition
EW/ ≥5 (1)

where W is the highest value, in joules, of the energy to be measured (see ISO 13802, Annex D, and

Note 2). The mass m , in kilograms, of the energy carrier must therefore satisfy inequalities (2) and (3):

* 2
mW≥ 10 /v (2)
C 0
mW≥=12,,when v 29ms/ (3)
C 0
e.g.
mW≥=12kg when 10J

NOTE 1 The height of the inertial peak F (see Figure 1, Curve b), and also the amplitudes of the subsequent

vibrations of the specimen, increase with increasing impact velocity. For basic information about these vibrations,

see Annex A and references [1] and [2] in Annex C. For further information about the interpretation of the inertial

peak and the damping of vibrations, see Annex A.

NOTE 2 For special applications, e.g. testing precracked test specimens to obtain data on fracture properties, it

may be useful to use a lower impact velocity of e.g. 1 m/s ± 0,05 m/s to reduce the vibrations mentioned in Note 1.

NOTE 3 This condition is in accordance with the conditions given in ISO 179-1, 7.3 (see ISO 13802, Annex D).

It ensures that the change in velocity during impact is comparable to that in conventional impact testing, and

consequently the values of impact strength are comparable. This is important, because plastics are bending-rate-

sensitive, especially at temperatures close to transition temperatures.
5.1.3 Striking edge
See ISO 13802, Annex A.

Any material with sufficient resistance to wear and sufficiently high strength to prevent it from being

deformed, as well as being capable of transmitting the forces exerted upon the specimen to the load-

measuring device, can be used for the striking edge.

NOTE Experience shows that steel is generally suitable. However, a material of lower density, e.g. titanium,

can be used to increase the natural frequency of the load-measuring system.
5.1.4 Pendulum
The pendulum shall conform to ISO 13802, 6.3 and Annex A.
5.1.5 Test specimen supports
The test specimen supports shall conform to ISO 13802, 6.3 and Annex A.
5.1.6 Frame

The frame of the test machine shall be capable of being levelled so that the striker and the specimen

supports conform to 5.1.3 and 5.1.5.

When calculating deflections from the kinetic energy of the energy carrier, the ratio m /m of the mass

F C

of the frame to the mass of the energy carrier shall be at least 10 (see Annex B and Notes 1 and 2 below).

For directly measured deflections, this ratio is a recommendation only. Impact-testing machines are

8 © ISO 2018 – All rights reserved
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oSIST prEN ISO 179-2:2018
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generally susceptible to acoustic vibrations. Therefore, the centre of gravity of the frame sh

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Questions, Comments and Discussion

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