Rigid cellular plastics - Determination of compression properties (ISO 844:2021)

This document specifies methods for determining the compressive strength and corresponding relative
deformation, the compressive stress at 10 % relative deformation, and the compressive modulus of
rigid cellular plastics.

Harte Schaumstoffe - Bestimmung der Druckeigenschaften (ISO 844:2021)

Dieses Dokument legt Verfahren zur Bestimmung der Druckfestigkeit und der zugehörigen Stauchung, der Druckspannung bei 10 % relativer Stauchung und des Druckmoduls für harte Schaumstoffe fest.

Plastiques alvéolaires rigides - Détermination des caractéristiques de compression (ISO 844:2021)

Penjeni polimerni materiali - Trde pene - Ugotavljanje lastnosti stiskanja (ISO 844:2021)

General Information

Status
Published
Public Enquiry End Date
16-Sep-2019
Publication Date
04-May-2021
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
03-May-2021
Due Date
08-Jul-2021
Completion Date
05-May-2021

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SLOVENSKI STANDARD
SIST EN ISO 844:2021
01-junij-2021
Nadomešča:
SIST EN ISO 844:2014
Penjeni polimerni materiali - Trde pene - Ugotavljanje lastnosti stiskanja (ISO
844:2021)
Rigid cellular plastics - Determination of compression properties (ISO 844:2021)
Harte Schaumstoffe - Bestimmung der Druckeigenschaften (ISO 844:2021)

Plastiques alvéolaires rigides - Détermination des caractéristiques de compression (ISO

844:2021)
Ta slovenski standard je istoveten z: EN ISO 844:2021
ICS:
83.100 Penjeni polimeri Cellular materials
SIST EN ISO 844:2021 en,fr,de

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

---------------------- Page: 1 ----------------------
SIST EN ISO 844:2021
---------------------- Page: 2 ----------------------
SIST EN ISO 844:2021
EN ISO 844
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2021
EUROPÄISCHE NORM
ICS 83.100 Supersedes EN ISO 844:2014
English Version
Rigid cellular plastics - Determination of compression
properties (ISO 844:2021)

Plastiques alvéolaires rigides - Détermination des Harte Schaumstoffe - Bestimmung der

caractéristiques de compression (ISO 844:2021) Druckeigenschaften (ISO 844:2021)
This European Standard was approved by CEN on 31 January 2021.

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

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 844:2021 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 844:2021
EN ISO 844:2021 (E)
Contents Page

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

---------------------- Page: 4 ----------------------
SIST EN ISO 844:2021
EN ISO 844:2021 (E)
European foreword

This document (EN ISO 844:2021) 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 October 2021, and conflicting national standards shall

be withdrawn at the latest by October 2021.

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 844:2014.

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 844:2021 has been approved by CEN as EN ISO 844:2021 without any modification.

---------------------- Page: 5 ----------------------
SIST EN ISO 844:2021
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SIST EN ISO 844:2021
INTERNATIONAL ISO
STANDARD 844
Seventh edition
2021-03
Rigid cellular plastics —
Determination of compression
properties
Plastiques alvéolaires rigides — Détermination des caractéristiques
de compression
Reference number
ISO 844:2021(E)
ISO 2021
---------------------- Page: 7 ----------------------
SIST EN ISO 844:2021
ISO 844:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 844:2021
ISO 844:2021(E)
Contents Page

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

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

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols .......................................................................................................................................................................................................................... 2

5 Principle ........................................................................................................................................................................................................................ 3

6 Apparatus ..................................................................................................................................................................................................................... 3

6.1 Compression-testing machine ................................................................................................................................................... 3

6.2 Devices for measuring displacement and force .......................................................................................................... 3

6.2.1 Measurement of displacement ............................................................................................................................ 3

6.2.2 Measurement of force .................................................................................................................................................. 4

6.2.3 Calibration ............................................................................................................................................................................. 4

6.3 Instruments for measuring the dimensions of the test specimens ........................................................... 4

7 Test specimens........................................................................................................................................................................................................ 4

7.1 Dimensions ................................................................................................................................................................................................. 4

7.2 Preparation ................................................................................................................................................................................................ 5

7.3 Number .......................................................................................................................................................................................................... 5

7.4 Conditioning .............................................................................................................................................................................................. 5

8 Procedure..................................................................................................................................................................................................................... 5

9 Expression of results ........................................................................................................................................................................................ 6

9.1 General ........................................................................................................................................................................................................... 6

9.2 Compressive strength and corresponding relative deformation ................................................................. 7

9.2.1 Compressive strength .................................................................................................................................................. 7

9.2.2 Nominal relative deformation (procedure A) ......................................................................................... 7

9.2.3 Relative deformation (procedure B) ............................................................................................................... 8

9.3 Compressive stress at 10 % nominal relative deformation (procedure A) ........................................ 8

9.4 Nominal compressive modulus of elasticity (procedure A) ............................................................................. 8

9.5 Compressive modulus of elasticity (procedure B) ................................................................................................... 9

10 Precision ....................................................................................................................................................................................................................... 9

10.1 Procedure A ............................................................................................................................................................................................... 9

10.2 Procedure B ............................................................................................................................................................................................10

11 Test report ................................................................................................................................................................................................................11

Annex A (informative) Remarks about the determination of the compressive modulus ...........................12

Bibliography .............................................................................................................................................................................................................................15

© ISO 2021 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 844:2021
ISO 844:2021(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 of 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 www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 10, Cellular

plastics, 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 seventh edition cancels and replaces the sixth edition (ISO 844:2014), which has been technically

revised. The main changes compared to the previous edition are as follows:

— different extensometer gage lengths have been given for use with different specimen thicknesses;

— repeatability and reproducibility results from the interlaboratory test on Procedure B have been

added for compressive strength and compressive modulus of elasticity measurements;

— Annex A has been added to provide information on the determination of the compressive modulus

by means Procedure B.

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 2021 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 844:2021
INTERNATIONAL STANDARD ISO 844:2021(E)
Rigid cellular plastics — Determination of compression
properties
1 Scope

This document specifies methods for determining the compressive strength and corresponding relative

deformation, the compressive stress at 10 % relative deformation, and the compressive modulus of

rigid cellular plastics.
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 1923, Cellular plastics and rubbers — Determination of linear dimensions

ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:

Tension/compression testing machines — Calibration and verification of the force-measuring system

ISO 9513, Metallic materials — Calibration of extensometer systems used in uniaxial testing

3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
nominal relative deformation (procedure A)

ratio of the reduction (in relation to its initial value) in thickness of the test specimen

Note 1 to entry: It is expressed as a percentage.

Note 2 to entry: ε is the nominal relative deformation corresponding to σ (see 3.3).

Cm m
3.2
relative deformation (procedure B)

ratio of the reduction (in relation to its initial value) of extensometer gauge length

Note 1 to entry: It is expressed as a percentage.
Note 2 to entry: ε is the relative deformation corresponding to σ (see 3.3).
m m
© ISO 2021 – All rights reserved 1
---------------------- Page: 11 ----------------------
SIST EN ISO 844:2021
ISO 844:2021(E)
3.3
compressive strength

maximum compressive force F divided by the initial cross-sectional area A of the test specimen when

m 0

the relative deformation ε and the nominal relative deformation ε respectively is < 10 %

Note 1 to entry: It is expressed in megapascals (MPa).
3.4
compressive stress at 10 % nominal relative deformation (procedure A)
C10

ratio of the compressive force F at 10 % nominal relative deformation ε to the initial cross-sectional

10 C10
area of the test specimen
Note 1 to entry: It is expressed in megapascals (MPa).
3.5
nominal compressive modulus of elasticity (procedure A)

difference in compressive stress divided by the difference in corresponding nominal relative

deformation below the proportional limit, i.e. when the relation is linear
Note 1 to entry: It is expressed in megapascals (MPa).
3.6
compressive modulus of elasticity (procedure B)

difference in compressive stress divided by the corresponding difference in relative deformation below

the proportional limit, i.e. when the relation is linear
Note 1 to entry: It is expressed in megapascals (MPa).
3.7
conventional proportional limit
upper limit of the linear part of the force - deformation curve
Note 1 to entry: It is expressed in millimetres (mm).
4 Symbols
Symbol Definition Unit
A initial cross-sectional area in square milli-
metres
E compressive modulus of elasticity in megapascals
E nominal compressive modulus of elasticity in megapascals
F force corresponding to x (conventional proportional limit) in newtons
e e
F force corresponding to x (nominal proportional limit) in newtons
Ce Ce
F maximum force in newtons
F force at 10 % nominal relative deformation in newtons
h initial thickness of test specimen (Procedure A) in millimetres
l initial gauge length of the extensometer (Procedure B) in millimetres
Ra surface roughness
t thickness

X displacement at F in the conventional elastic zone, (Procedure B) in millimetres

e e
X nominal displacement at F in the conventional ela
...

SLOVENSKI STANDARD
oSIST prEN ISO 844:2019
01-september-2019

Penjeni polimerni materiali - Trde pene - Ugotavljanje lastnosti stiskanja (ISO/DIS

844:2019)

Rigid cellular plastics - Determination of compression properties (ISO/DIS 844:2019)

Harte Schaumstoffe - Bestimmung der Druckeigenschaften (ISO/DIS 844:2019)

Plastiques alvéolaires rigides - Détermination des caractéristiques de compression

(ISO/DIS 844:2019)
Ta slovenski standard je istoveten z: prEN ISO 844
ICS:
83.100 Penjeni polimeri Cellular materials
oSIST prEN ISO 844:2019 en,fr,de

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

---------------------- Page: 1 ----------------------
oSIST prEN ISO 844:2019
---------------------- Page: 2 ----------------------
oSIST prEN ISO 844:2019
DRAFT INTERNATIONAL STANDARD
ISO/DIS 844
ISO/TC 61/SC 10 Secretariat: SCC
Voting begins on: Voting terminates on:
2019-06-25 2019-09-17
Rigid cellular plastics — Determination of compression
properties

Plastiques alvéolaires rigides — Détermination des caractéristiques de compression

ICS: 83.100
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 844:2019(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 2019
---------------------- Page: 3 ----------------------
oSIST prEN ISO 844:2019
ISO/DIS 844:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

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 2019 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 844:2019
ISO/DIS 844:2019(E)
Contents Page

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

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

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviated terms ........................................................................................................................................................... 3

5 Principle ........................................................................................................................................................................................................................ 4

6 Apparatus ..................................................................................................................................................................................................................... 4

6.1 Compression-testing machine ................................................................................................................................................... 4

6.2 Devices for measuring displacement and force .......................................................................................................... 5

6.2.1 Measurement of displacement ............................................................................................................................ 5

6.2.2 Measurement of force .................................................................................................................................................. 5

6.2.3 Calibration ............................................................................................................................................................................. 5

6.3 Instruments for measuring the dimensions of the test specimens ........................................................... 5

7 Test specimens........................................................................................................................................................................................................ 5

7.1 Dimensions ................................................................................................................................................................................................. 5

7.2 Preparation ................................................................................................................................................................................................ 6

7.3 Number .......................................................................................................................................................................................................... 6

7.4 Conditioning .............................................................................................................................................................................................. 6

8 Procedure..................................................................................................................................................................................................................... 6

9 Expression of results ........................................................................................................................................................................................ 7

9.1 General ........................................................................................................................................................................................................... 7

9.2 Compressive strength and corresponding relative deformation ................................................................. 8

9.2.1 Compressive strength .................................................................................................................................................. 8

9.2.2 Nominal relative deformation (procedure A) ......................................................................................... 8

9.2.3 Relative deformation (procedure B) ............................................................................................................... 9

9.3 Compressive stress at 10 % nominal relative deformation (procedure A) ........................................ 9

9.4 Nominal compressive modulus of elasticity (procedure A) ............................................................................. 9

9.5 Compressive modulus of elasticity (procedure B) ................................................................................................10

10 Precision ....................................................................................................................................................................................................................10

10.1 Procedure A ............................................................................................................................................................................................10

10.2 Procedure B ............................................................................................................................................................................................11

11 Test report ................................................................................................................................................................................................................12

Annex A (informative) Remarks about the determination of the compressive modulus ...........................13

© ISO 2019 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 844:2019
ISO/DIS 844:2019(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 meaning of ISO specific terms and expressions related to conformity

assessment, as well as information about ISO's adherence to the WTO principles in the Technical

Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information

The committee responsible for this document is ISO/TC 61, Plastics, Subcommittee SC 10, Cellular

plastics.

This sixth edition cancels and replaces the fifth edition (ISO 844:2007), which has been technically

revised to specify the choice of the procedure for the determination of the compressive strength and

corresponding relative deformation, the compressive stress at 10 % relative deformation and the

compressive modulus of rigid cellular plastics.
iv © ISO 2019 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 844:2019
DRAFT INTERNATIONAL STANDARD ISO/DIS 844:2019(E)
Rigid cellular plastics — Determination of compression
properties
1 Scope

This document specifies methods for determining the compressive strength and corresponding relative

deformation; the compressive stress at 10 % relative deformation; and the compressive modulus of

rigid cellular plastics.

Two methods are given. Procedure A employs crosshead motion for determination of nominal

compressive properties. Procedure B employs displacement measuring device (including contact and

optical types).
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. 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 1923, Cellular plastics and rubbers — Determination of linear dimensions

ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:

Tension/compression testing machines — Calibration and verification of the force-measuring system

ISO 9513, Metallic materials — Calibration of extensometer systems used in uniaxial testing

ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method

for the determination of repeatability and reproducibility of a standard measurement method

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
nominal relative deformation (procedure A)

ratio of the reduction (in relation to its initial value) in thickness of the test specimen

Note 1 to entry: It is expressed as a percentage.

Note 2 to entry: ε is the nominal relative deformation corresponding to σ (see 3.3).

Cm m
3.2
relative deformation (procedure B)

ratio of the reduction (in relation to its initial value) of extensometer gauge length

Note 1 to entry: It is expressed as a percentage.
Note 2 to entry: ε is the relative deformation corresponding to σ (see 3.3).
m m
© ISO 2019 – All rights reserved 1
---------------------- Page: 7 ----------------------
oSIST prEN ISO 844:2019
ISO/DIS 844:2019(E)
3.3
compressive strength (procedure A or B)

maximum compressive force F divided by the initial cross-sectional area A of the test specimen when

m 0

the relative deformation ε and the nominal relative deformation ε respectively is < 10 %

Note 1 to entry: It is expressed in megapascals (MPa).
3.4
compressive stress at 10 % nominal relative deformation (procedure A)
C10

ratio of the compressive force F at 10 % nominal relative deformation ε to the initial cross-sectional

10 C10
area of the test specimen
Note 1 to entry: It is expressed in megapascals (MPa).
3.5
nominal compressive modulus of elasticity (procedure A)

difference in compressive stress divided by the difference in corresponding nominal relative

deformation below the proportional limit, i.e. when the relation is linear
Note 1 to entry: It is expressed in megapascals (MPa).
3.6
compressive modulus of elasticity (procedure B)

difference in compressive stress divided by the corresponding difference in relative deformation below

the proportional limit, i.e. when the relation is linear
Note 1 to entry: It is expressed in megapascals (MPa).
3.7
Cross sectional area

the initial cross sectional area of the test specimen perpendicular to the loading direction

Note 1 to entry: It is expressed in square millimetres mm .
3.8
Conventional proportional limit
the upper limit of the linear part of the force - deformation curve
Note 1 to entry: It is expressed in millimetres (mm).
3.9
Force at proportional limit
the force corresponding to x (conventional proportional limit)
Note 1 to entry: It is expressed in newtons (N).
3.10
Maximum Force
the maximum force transferred by the test specimen
Note 1 to entry: It is expressed in newtons (N).
2 © ISO 2019 – All rights reserved
---------------------- Page: 8 ----------------------
oSIST prEN ISO 844:2019
ISO/DIS 844:2019(E)
3.11
Force at 10% nominal relative deformation
the force transferred by the test specimen at 10% nominal relative deformation
Note 1 to entry: It is expressed in newtons (N).
3.12
Initial thickness
the initial thickness of test specimen (Procedure A)
Note 1 to entry: It is expressed in millimetres (mm).
3.13
Initial gauge length
the initial extensometer gauge length (Procedure B)
Note 1 to entry: It is expressed in millimetres (mm).
3.14
displacement

the displacement of the moving plate versus the fixed plate during the test (Procedure A) and

displacement of extensometer respectively (Procedure B)
X displacement at maximum force F
m m
X nominal displacement at maximum force F
Cm m
X nominal displacement at 10 % nominal relative deformation
C10
Note 1 to entry: It is expressed in millimetres (mm).
4 Symbols and abbreviated terms
A initial cross-sectional area, in square millimetres
E compressive modulus of elasticity, in megapascals
E nominal compressive modulus of elasticity, in megapascals
F force corresponding to x (conventional proportional limit), in newtons
e e
F force corresponding to x (conventional proportional limit), in newtons
Ce Ce
F maximum force, in newtons
F force at 10 % nominal relative deformation, in newtons
h initial thickness of test specimen (Procedure A), in millimetres
l initial gauge length of the extensometer (Procedure B), in millimetres

X displacement at F in the conventional elastic zone, in millimetres (Procedure B)

e e

X nominal displacement at F in the conventional elastic zone, in millimetres (Procedure A)

Ce Ce
X displacement at maximum force, in millimetres
© ISO 2019 – All rights reserved 3
---------------------- Page: 9 ----------------------
oSIST prEN ISO 844:2019
ISO/DIS 844:2019(E)
X nominal displacement at maximum force, in millimetres
X displacement at 10 % nominal relative deformation, in millimetres
C10
ε relative deformation corresponding to compressive strength σ , in percent
m m

ε nominal relative deformation corresponding to compressive strength σ , in percent

Cm m
ε 10 % nominal relative deformation, in percent
C10
σ compressive strength, in megapascals
σ compressive stress at 10 % nominal relative deformation, in megapascals
5 Principle

A compressive force is applied in an axial direction and perpendicular to the faces

...

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