SIST EN ISO 899-1:2018
(Main)Plastics - Determination of creep behaviour - Part 1: Tensile creep (ISO 899-1:2017)
Plastics - Determination of creep behaviour - Part 1: Tensile creep (ISO 899-1:2017)
This document specifies a method for determining the tensile creep of plastics in the form of standard test specimens under specified conditions such as those of pretreatment, temperature and humidity.
The method is suitable for use with rigid and semi-rigid non-reinforced, filled and fibre-reinforced plastics materials in the form of dumb-bell-shaped test specimens moulded directly or machined from sheets or moulded articles.
The method is intended to provide data for engineering-design and research and development purposes.
Data for engineering-design purposes requires the use of extensometers to measure the gauge length
of the specimen. Data for research or quality-control purposes may use the change in distance between the grips (nominal extension).
Tensile creep can vary significantly with differences in specimen preparation and dimensions and in the test environment. The thermal history of the test specimen can also have profound effects on its creep behaviour (see Annex A). Consequently, when precise comparative results are required, these factors are intended to be carefully controlled.
If tensile-creep properties are used for engineering-design purposes, the plastics materials are intended to be tested over a broad range of stresses, times and environmental conditions.
Kunststoffe - Bestimmung des Kriechverhaltens - Teil 1: Zeitstand-Zugversuch (ISO 899-1:2017)
Plastiques - Détermination du comportement au fluage - Partie 1: Fluage en traction (ISO 899-1:2017)
L'ISO 899-1 spécifie une méthode de détermination du fluage en traction des plastiques sous forme d'éprouvettes normalisées dans des conditions spécifiées, telles qu'en matière de traitement préalable, température et humidité.
Cette méthode est destinée aux plastiques rigides et semi rigides, non renforcés, chargés et renforcés par des fibres sous forme d'éprouvettes en forme d'haltères moulées directement ou usinées à partir de feuilles ou d'objets moulés.
Cette méthode est proposée pour fournir des données utiles pour la conception en ingénierie, la recherche et le développement. Les données utiles pour la conception en ingénierie nécessitent l'emploi d'extensomètres positionnés sur la longueur de référence de l'éprouvette. Les données pour la recherche ou le contrôle qualité peuvent utiliser la méthode de fluage en traction nominale.
Le fluage en traction peut dépendre étroitement des différences existant en matière de dimensions et préparation des éprouvettes ainsi qu'en ce qui concerne l'environnement d'essai. L'histoire thermique de l'éprouvette peut également influencer profondément son comportement au fluage (voir Annexe A). En conséquence, lorsque des résultats comparatifs précis sont requis, ces facteurs sont destinés à être soigneusement contrôlés.
Si les caractéristiques de fluage en traction sont destinées à des fins de conception en ingénierie, les matériaux plastiques sont destinés à être soumis à essai dans une large gamme de contraintes, durées et environnements.
Polimerni materiali - Ugotavljanje lezenja - 1. del: Lezenje pri natezni obremenitvi (ISO 899-1:2017)
Ta dokument določa metodo za določevanje lezenja pri natezni obremenitvi polimernih materialov v obliki standardnih preskusnih vzorcev pod določenimi pogoji, npr. pogoji za predhodno obdelavo, temperaturo in vlago.
Metoda je primerna za uporabo s preskusnimi vzorci trdih in poltrdih neojačenih polimernih materialov, polnjenih polimernih materialov ter z vlakni ojačanih polimernih materialov v obliki ročke, ki so neposredno oblikovani oziroma izdelani iz trakov ali oblikovanih predmetov.
Cilj metode je zagotoviti podatke za namene načrtovanja in razvoja.
Za pridobivanje podatkov za namene načrtovanja je treba uporabiti ekstenzometre za merjenje dolžine preskusnega
vzorca. Podatki za namene raziskav ali nadzora kakovosti lahko uporabljajo razliko v razdalji med prižemkami (nazivna razteznost).
Lezenje pri natezni obremenitvi se lahko znatno razlikuje zaradi razlik pri pripravi vzorcev, različnih velikosti vzorcev in razlik v preskusnem okolju. Pretekla temperatura vzorca lahko tudi močno vpliva na njegovo lezenje pri natezni napetosti (glej dodatek A). Zato je za natančne primerljive rezultate treba te dejavnike natančno nadzirati.
Če se lastnosti lezenja pri natezni obremenitvi uporabljajo za namene načrtovanja, je treba polimerne materiale preskusiti pod različnimi obremenitvami, z različnimi časi obremenitve in pri različnih okoljskih pogojih.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 899-1:2018
01-februar-2018
1DGRPHãþD
SIST EN ISO 899-1:2003
SIST EN ISO 899-1:2003/A1:2015
Polimerni materiali - Ugotavljanje lezenja - 1. del: Lezenje pri natezni obremenitvi
(ISO 899-1:2017)
Plastics - Determination of creep behaviour - Part 1: Tensile creep (ISO 899-1:2017)
Kunststoffe - Bestimmung des Kriechverhaltens - Teil 1: Zeitstand-Zugversuch (ISO 899-
1:2017)
Plastiques - Détermination du comportement au fluage - Partie 1: Fluage en traction (ISO
899-1:2017)
Ta slovenski standard je istoveten z: EN ISO 899-1:2017
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
SIST EN ISO 899-1:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN ISO 899-1:2018
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SIST EN ISO 899-1:2018
EN ISO 899-1
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2017
EUROPÄISCHE NORM
ICS 83.080.01 Supersedes EN ISO 899-1:2003
English Version
Plastics - Determination of creep behaviour - Part 1:
Tensile creep (ISO 899-1:2017)
Plastiques - Détermination du comportement au fluage Kunststoffe - Bestimmung des Kriechverhaltens - Teil
- Partie 1: Fluage en traction (ISO 899-1:2017) 1: Zeitstand-Zugversuch (ISO 899-1:2017)
This European Standard was approved by CEN on 31 October 2017.
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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 899-1:2017 E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 899-1:2018
EN ISO 899-1:2017 (E)
Contents Page
European foreword . 3
2
---------------------- Page: 4 ----------------------
SIST EN ISO 899-1:2018
EN ISO 899-1:2017 (E)
European foreword
This document (EN ISO 899-1:2017) 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 May 2018, and conflicting national standards shall be
withdrawn at the latest by May 2018.
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 899-1:2003.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 899-1:2017 has been approved by CEN as EN ISO 899-1:2017 without any modification.
3
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SIST EN ISO 899-1:2018
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SIST EN ISO 899-1:2018
INTERNATIONAL ISO
STANDARD 899-1
Third edition
2017-09
Plastics — Determination of creep
behaviour —
Part 1:
Tensile creep
Plastiques — Détermination du comportement au fluage —
Partie 1: Fluage en traction
Reference number
ISO 899-1:2017(E)
©
ISO 2017
---------------------- Page: 7 ----------------------
SIST EN ISO 899-1:2018
ISO 899-1:2017(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. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 899-1:2018
ISO 899-1:2017(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Apparatus . 3
5 Test specimens. 4
6 Procedure. 4
6.1 Conditioning and test atmosphere . 4
6.2 Measurement of test-specimen dimensions . 5
6.3 Mounting the test specimens . 5
6.4 Selection of stress value . 5
6.5 Loading procedure . 5
6.5.1 Preloading . 5
6.5.2 Loading . 5
6.6 Extension-measurement schedule . 5
6.7 Time measurement . 5
6.8 Temperature and humidity control . 6
6.9 Measurement of recovery rate (optional) . 6
7 Expression of results . 6
7.1 Method of calculation . 6
7.1.1 Tensile-creep modulus, E . 6
t
7.1.2 Nominal tensile-creep modulus, E* . 6
t
7.2 Presentation of results . 7
7.2.1 Creep curves . 7
7.2.2 Creep-modulus/time curves . 7
7.2.3 Isochronous stress-strain curves . 8
7.2.4 Three-dimensional representation . 8
7.2.5 Creep-to-rupture curves. 8
7.3 Precision . 9
8 Test report . 9
Annex A (informative) Physical-ageing effects on the creep of polymers .10
Bibliography .14
© ISO 2017 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 899-1:2018
ISO 899-1:2017(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: www.iso.org/iso/foreword.html
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 2,
Mechanical behaviour.
This third edition cancels and replaces the second edition (ISO 899-1:2003), of which it constitutes a
minor revision to update the normative references in Clause 2. It also incorporates the Amendment
ISO 899-1:2003/Amd.1:2015.
A list of all parts in the ISO 899 series can be found on the ISO website.
iv © ISO 2017 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 899-1:2018
INTERNATIONAL STANDARD ISO 899-1:2017(E)
Plastics — Determination of creep behaviour —
Part 1:
Tensile creep
1 Scope
This document specifies a method for determining the tensile creep of plastics in the form of standard
test specimens under specified conditions such as those of pretreatment, temperature and humidity.
The method is suitable for use with rigid and semi-rigid non-reinforced, filled and fibre-reinforced
plastics materials in the form of dumb-bell-shaped test specimens moulded directly or machined from
sheets or moulded articles.
The method is intended to provide data for engineering-design and research and development purposes.
Data for engineering-design purposes requires the use of extensometers to measure the gauge length
of the specimen. Data for research or quality-control purposes may use the change in distance between
the grips (nominal extension).
Tensile creep can vary significantly with differences in specimen preparation and dimensions and in
the test environment. The thermal history of the test specimen can also have profound effects on its
creep behaviour (see Annex A). Consequently, when precise comparative results are required, these
factors are intended to be carefully controlled.
If tensile-creep properties are used for engineering-design purposes, the plastics materials are intended
to be tested over a broad range of stresses, times and environmental conditions.
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 291, Plastics — Standard atmospheres for conditioning and testing
ISO 472, Plastics — Vocabulary
ISO 527-1:2012, Plastics — Determination of tensile properties — Part 1: General principles
ISO 527-2, Plastics — Determination of tensile properties — Part 2: Test conditions for moulding and
extrusion plastics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 472 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
---------------------- Page: 11 ----------------------
SIST EN ISO 899-1:2018
ISO 899-1:2017(E)
3.1
creep
increase in strain with time when a constant force is applied
3.2
initial stress
σ
tensile force per unit area of the initial cross-section within the gauge length
Note 1 to entry: It is given by the formula
F
σ =
A
where
F is the force, in newtons;
A is the average initial cross-sectional area within the narrow (gauge) section of the specimen, in square
millimetres.
Note 2 to entry: It is expressed in megapascals.
3.3
extension
(ΔL)
t
increase in the distance between the gauge marks, expressed in millimetres, at time t
Note 1 to entry: It is given by the formula
()ΔLL=−L
tt 0
where
L is the gauge length, in millimetres, at any given time t during the test;
t
L is the original gauge length, in millimetres, of the specimen after application of a preload but prior to
0
application of the test load.
3.4
nominal extension
(ΔL*)
t
increase in the distance between the grips (increase in grip separation)
Note 1 to entry: It is given by the formula
∗∗ ∗
()ΔLL=− L
tt 0
where
L* is the distance between the grips at any given time t during the test, in millimetres;
t
L* is the initial distance between the grips, expressed in millimetres, holding the specimen after application
0
of a preload but prior to application of the test load.
2 © ISO 2017 – All rights reserved
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SIST EN ISO 899-1:2018
ISO 899-1:2017(E)
3.5
tensile-creep strain
ε
t
change in the distance between the gauge marks, relative to the initial distance, produced by the applied
load at any given time t during a creep test
Note 1 to entry: It is given by the formula
()ΔL
t
ε =
t
L
0
Note 2 to entry: It is expressed as a dimensionless ratio or as a percentage.
3.6
nominal tensile-creep strain
ε*
t
change in the distance between the grips, relative to the initial distance, produced by the applied load
at any given time t during a creep test
Note 1 to entry: It is given by the formula
∗
()ΔL
∗ t
ε =
t
∗
L
0
Note 2 to entry: It is expressed as a dimensionless ratio or as a percentage.
3.7
tensile-creep modulus
E
t
ratio of initial stress to tensile-creep strain
3.8
nominal tensile-creep modulus
E*
t
ratio of initial stress to nominal tensile-creep strain
3.9
isochronous stress-strain curve
Cartesian plot of stress versus creep strain, at a specific time after application of the test load
3.10
time to rupture
period of time the specimen is under full load until rupture
3.11
creep-strength limit
initial stress which will just cause rupture (σ ) or will produce a specified strain (σ ) at a specified
B,t ε,t
time t, at a given temperature and relative humidity
3.12
recovery from creep
decrease in strain at any given time after completely unloading the specimen, expressed as a percentage
of the strain just prior to the removal of the load
4 Apparatus
4.1 Gripping device, capable of ensuring that the direction of the load applie
...
SLOVENSKI STANDARD
oSIST prEN ISO 899-1:2017
01-julij-2017
Polimerni materiali - Ugotavljanje lezenja - 1. del: Lezenje pri natezni obremenitvi
(ISO/FDIS 899-1:2017)
Plastics - Determination of creep behaviour - Part 1: Tensile creep (ISO/FDIS 899-
1:2017)
Kunststoffe - Bestimmung des Kriechverhaltens - Teil 1: Zeitstand-Zugversuch
(ISO/FDIS 899-1:2017)
Plastiques - Détermination du comportement au fluage - Partie 1: Fluage en traction
(ISO/FDIS 899-1:2017)
Ta slovenski standard je istoveten z: prEN ISO 899-1
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
oSIST prEN ISO 899-1:2017 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 899-1:2017
---------------------- Page: 2 ----------------------
oSIST prEN ISO 899-1:2017
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 899-1
ISO/TC 61/SC 2
Plastics — Determination of creep
Secretariat: SAC
behaviour —
Voting begins on:
2017-05-23
Part 1:
Voting terminates on:
Tensile creep
2017-08-15
Plastiques — Détermination du comportement au fluage —
Partie 1: Fluage en traction
ISO/CEN PARALLEL PROCESSING
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 SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 899-1:2017(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2017
---------------------- Page: 3 ----------------------
oSIST prEN ISO 899-1:2017
ISO/FDIS 899-1:2017(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. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 899-1:2017
ISO/FDIS 899-1:2017(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Apparatus . 3
5 Test specimens. 4
6 Procedure. 4
6.1 Conditioning and test atmosphere . 4
6.2 Measurement of test-specimen dimensions . 5
6.3 Mounting the test specimens . 5
6.4 Selection of stress value . 5
6.5 Loading procedure . 5
6.5.1 Preloading . 5
6.5.2 Loading . 5
6.6 Extension-measurement schedule . 5
6.7 Time measurement . 5
6.8 Temperature and humidity control . 6
6.9 Measurement of recovery rate (optional) . 6
7 Expression of results . 6
7.1 Method of calculation . 6
7.1.1 Tensile-creep modulus, E . 6
t
7.1.2 Nominal tensile-creep modulus, E* . 6
t
7.2 Presentation of results . 7
7.2.1 Creep curves . 7
7.2.2 Creep-modulus/time curves . 7
7.2.3 Isochronous stress-strain curves . 8
7.2.4 Three-dimensional representation . 8
7.2.5 Creep-to-rupture curves. 8
7.3 Precision . 9
8 Test report . 9
Annex A (informative) Physical-ageing effects on the creep of polymers .10
Bibliography .14
© ISO 2017 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 899-1:2017
ISO/FDIS 899-1:2017(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 61, Plastics, Subcommittee SC 2,
Mechanical behaviour.
This third edition cancels and replaces the second edition (ISO 899-1:2003), of which it constitutes a
minor revision to update the normative references in Clause 2. It also incorporates the Amendment
ISO 899-1:2003/Amd.1:2015.
A list of all parts in the ISO 899 series can be found on the ISO website.
iv © ISO 2017 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 899-1:2017
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 899-1:2017(E)
Plastics — Determination of creep behaviour —
Part 1:
Tensile creep
1 Scope
This document specifies a method for determining the tensile creep of plastics in the form of standard
test specimens under specified conditions such as those of pretreatment, temperature and humidity.
The method is suitable for use with rigid and semi-rigid non-reinforced, filled and fibre-reinforced
plastics materials in the form of dumb-bell-shaped test specimens moulded directly or machined from
sheets or moulded articles.
The method is intended to provide data for engineering-design and research and development purposes.
Data for engineering-design purposes requires the use of extensometers to measure the gauge length
of the specimen. Data for research or quality-control purposes may use the change in distance between
the grips (nominal extension).
Tensile creep can vary significantly with differences in specimen preparation and dimensions and in
the test environment. The thermal history of the test specimen can also have profound effects on its
creep behaviour (see Annex A). Consequently, when precise comparative results are required, these
factors are intended to be carefully controlled.
If tensile-creep properties are used for engineering-design purposes, the plastics materials are intended
to be tested over a broad range of stresses, times and environmental conditions.
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 291, Plastics — Standard atmospheres for conditioning and testing
ISO 472, Plastics — Vocabulary
ISO 527-1:2012, Plastics — Determination of tensile properties — Part 1: General principles
ISO 527-2, Plastics — Determination of tensile properties — Part 2: Test conditions for moulding and
extrusion plastics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 472 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
---------------------- Page: 7 ----------------------
oSIST prEN ISO 899-1:2017
ISO/FDIS 899-1:2017(E)
3.1
creep
increase in strain with time when a constant force is applied
3.2
initial stress
σ
tensile force per unit area of the initial cross-section within the gauge length
Note 1 to entry: It is given by the formula
F
σ =
A
where
F is the force, in newtons;
A is the average initial cross-sectional area within the narrow (gauge) section of the specimen, in square
millimetres.
Note 2 to entry: It is expressed in megapascals.
3.3
extension
(ΔL)
t
increase in the distance between the gauge marks, expressed in millimetres, at time t
Note 1 to entry: It is given by the formula
()ΔLL=−L
tt 0
where
L is the gauge length, in millimetres, at any given time t during the test;
t
L is the original gauge length, in millimetres, of the specimen after application of a preload but prior to
0
application of the test load.
3.4
nominal extension
(ΔL*)
t
increase in the distance between the grips (increase in grip separation)
Note 1 to entry: It is given by the formula
∗∗ ∗
()ΔLL=− L
tt 0
where
L* is the distance between the grips at any given time t during the test, in millimetres;
t
L* is the initial distance between the grips, expressed in millimetres, holding the specimen after application
0
of a preload but prior to application of the test load.
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3.5
tensile-creep strain
ε
t
change in the distance between the gauge marks, relative to the initial distance, produced by the applied
load at any given time t during a creep test
Note 1 to entry: It is given by the formula
()ΔL
t
ε =
t
L
0
Note 2 to entry: It is expressed as a dimensionless ratio or as a percentage.
3.6
nominal tensile-creep strain
ε*
t
change in the distance between the grips, relative to the initial distance, produced by the applied load
at any given time t during a creep test
Note 1 to entry: It is given by the formula
∗
()ΔL
∗ t
ε =
t
∗
L
0
Note 2 to entry: It is expressed as a dimensionless ratio or as a percentage.
3.7
tensile-creep modulus
E
t
ratio of initial stress to tensile-creep strain
3.8
nominal tensile-creep modulus
E*
t
ratio of initial stress to nominal tensile-creep strain
3.9
isochronous stress-strain curve
Cartesian plot of stress versus creep strain, at a specific time after application of the test load
3.10
time to rupture
period of time the specimen is under full load until rupture
3.11
creep-strength limit
initial stress which will just cause rupture (σ ) or will produce a specified strain (σ ) at a specified
B,t ε,t
time t, at a given temperature and relative humidity
3.12
recovery from creep
decrease in strain at any given time after completely unloading the specimen, expressed as a percentage
of the strain just prior to the removal of the load
4 Apparatus
4.1 Gripping device, capable of ensuring that the direction of the load applied to the test specimen
coincides as closely as possible with the longitudinal axis of the specimen. This ensures that the test
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specimen is subjected to simple stress and that the stresses in the loaded section of the specimen may be
assumed to be uniformly distributed over cross-sections perpendicular to the direction of the applied load.
It is recommended that grips be used that will allow the specimen to be fixed in place, correctly aligned,
prior to applying the load. Self-locking grips which allow the specimen to move as the load increases are
not suitable for this test.
4.2 Loading system, capable of ensuring that the load is applied smoothly, without causing transient
overloading, and that the load is maintained to within ± 1 % of the desired load. In creep-to-rupture tests,
provision shall be made to prevent any shocks which occur at the moment of rupture being transmitted
to adjacent loading systems. The loading mechanism shall allow rapid, smooth and reproducible loading.
4.3 Extension-measuring device, comprising any contactless or contact device capable of measuring
the extension of the specimen gauge length or the increase in the distance between the clamp grips under
load without influencing the specimen behaviour by mechanical effects (e.g. undesirable deformations,
notches), other physical effects (e.g. heating of the specimen) or chemical effects.
In the case of contactless (optical) measurement of the strain, the longitudinal axis of the specimen
...
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