ISO 20975-1:2023

INTERNATIONAL ISO
STANDARD 20975-1
First edition
2023-01
Fibre-reinforced plastic composites —
Determination of laminate through-
thickness properties —
Part 1:
Direct tension and compression tests
Composites plastiques renforcés de fibres — Détermination des
propriétés dans l'épaisseur d'un composite stratifié —
Partie 1: Essais directs de traction et de compression
Reference number
© ISO 2023
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
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 4
5 Apparatus . 4
5.1 Test machine . 4
5.1.1 General . 4
5.1.2 Indicators for load and strain . 5
5.2 Strain gauges and strain acquisition . 5
5.3 Micrometer . 5
5.4 Loading fixtures . 5
5.4.1 General . 5
5.4.2 Method A - Tension loading . . 5
5.4.3 Method B - Compression loading . 5
6 Test specimens . 6
6.1 Shape and dimensions . 6
6.1.1 Type I specimens . 6
6.1.2 Type II specimens . 7
6.1.3 Type III specimens . 8
6.1.4 Non-standard test specimens . 9
6.2 Preparation of test specimens . 10
6.2.1 General . 10
6.2.2 Parallelism . 10
6.2.3 Application of end-loading blocks for Method A — Tension only . 10
6.3 Checking . 10
7 Test specimens .10
8 Conditioning .11
9 Test procedure .11
9.1 Test atmosphere . 11
9.2 Specimen dimensions . 11
9.3 Specimen preparation Method A — Tension only . 11
9.4 Strain recording . 11
9.5 Specimen alignment. 11
9.5.1 Method A – Tension . 11
9.5.2 Method B – Compression .12
9.6 Testing speed, v .12
9.7 Data collection .12
9.8 Maximum load .12
9.9 Failure mode .12
9.10 Test acceptance .12
10 Expression of results .12
10.1 Method A — Tension .12
10.1.1 Tensile strength .12
10.1.2 Modulus of elasticity (chord) in tension . 13
10.1.3 Tensile failure strain . 14
10.2 Method B — Compression . 14
10.2.1 Compressive strength . 14
10.2.2 Modulus of elasticity (chord) in compression . 15
iii
10.2.3 Compressive failure strain . 15
10.3 Poisson’s ratio – Methods A and B . 15
10.4 Statistical analysis . 16
11 Precision .16
12 Test report .16
Annex A (informative) Precision data .17
Bibliography .19
iv
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 13,
Composites and reinforcement fibres.
A list of all parts in the ISO 20975 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.
v
...