EN ISO 14129:1997

Fibre-reinforced plastic composites - Determination of the in-plane shear stress/shear strain response, including the in-plane shear modulus and strength, by the +/- 45° tension test method (ISO 14129:1997)

This International Standard specifies a procedure for determining the in-plane shear stress-shear strain, shear modulus and shear strength of fibre-reinforced plastic composites by the +/- 45° tension test method. The method is suitable f for use with the following materials: - thermoset and thermoplastic matrix laminates made from unidirectional layers and/or fabrics including unidirectional fabrics, with the fibres oriented at +/- 45° to the specimen axis. the lay-up shall be symmetrical and balanced about the specimen mid-plane.

Faserverstärkte Kunststoffe - Zugversuch an 45°-Laminaten zur Bestimmung der Schubspannungs/Schubverformungs-Kurve, des Schubmoduls und der Schubfestigkeit in der Lagenebene (ISO 14129:1997)

Diese Internationale Norm legt ein Verfahren zur Bestimmung der Schubspannungs- Schubverformungs-Kurve, des Schubmoduls und der Schubfestigkeit von faserverstärkten Kunststoffen im Zugversuch an 45°-Laminaten in der Lagenebene fest. Das Verfahren ist anwendbar auf Laminate, die aus einer thermoplastischen oder duroplastischen Grundmasse und aus unidirektionalen Lagen und/oder Geweben, einschließlich unidirektionaler Gewebe mit einer Faserorientierung von +/- 45° zur Probekörperachse bestehen.

Composites plastiques renforcés de fibres - Détermination de la réponse contrainte-déformation en cisaillement plan, module et résistance compris, par essai de traction à +/- 45° (ISO 14129:1997)

1.1 La présente Norme internationale prescrit une méthode pour la détermination de la réponse contrainte-déformation en cisaillement plan, module et résistance compris, des composites plastiques renforcés de fibre par l'essai de traction à ± 45°. 1.2 La méthode est applicable aux stratifiés à matrice thermodurcissable et matrice thermoplastique fabriqués à partir de couches unidirectionnelles et/ou de tissus, y compris les tissus unidirectionnels, dont les fibres sont orientées à ± 45° par rapport à l'axe de l'éprouvette; la disposition des couches doit être équilibrée et symétrique par rapport au plan moyen de l'éprouvette.  
NOTE -- Cette méthode ne convient pas aux tissus grossiers. 1.3 Étant donné que le nombre et la répartition des couches influencent l'essai, il convient de veiller à ce que les comparaisons soient effectuées en utilisant le même nombre de couches et que celles-ci soient bien réparties.

Z vlakni ojačeni kompozitni polimerni materiali – Določevanje odvisnosti strižne napetosti od strižne deformacije vključno s strižnim modulom in strižno trdnostjo v ravnini - 45° preskus (ISO 14129:1997)

General Information

• Status: Published
• Publication Date: 14-Dec-1997
• Withdrawal Date: 29-Jun-1998
• ICS: 83.120 - Reinforced plastics
• ICS: 83.140.20 - Laminated sheets
• Technical Committee: CEN/TC 249 - Plastics
• Drafting Committee: CEN/TC 249/SC 2/WG 5 - Structural properties
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 15-Dec-1997
• Completion Date: 15-Dec-1997
• Ref Project: SIST EN ISO 14129:1999 - Fibre-reinforced plastic composites - Determination of the in-plane shear stress/shear strain response, including the in-plane shear modulus and strength, by the +/- 45° tension test method (ISO 14129:1997)

Overview

EN ISO 14129:1997 defines the ±45° tension test method to determine the in‑plane shear stress–shear strain response, including the in‑plane shear modulus and shear strength, of fibre‑reinforced plastic composites. The procedure is applicable to thermoset and thermoplastic matrix laminates manufactured from unidirectional layers and/or fabrics where the plies are arranged symmetrically and balanced about the mid-plane.

The standard emphasises practical measurement and test control for reliable material data used in design, material selection and quality control of composite components.

Key Topics

• Scope and applicability: Suitable for unidirectional and fabric laminates with fibres at ±45° to the specimen axis; not recommended for coarse fabrics.
• Specimen geometry: Typical specimen width 25 mm, length 250 mm, nominal thickness 2 mm (values and tolerances are stated in the standard). For layers thicker than 0.125 mm, a 16‑layer laminate is specified.
• Test setup and instrumentation:
  • Strain measurement both parallel and perpendicular to the specimen axis using strain gauges or extensometers.
  • Load measurement per ISO 5893 with accuracy better than ±1% full scale.
  • Typical test speed: 2 mm/min (unless material-specific conditions apply).
• Termination and failure criterion: Tests are terminated at a shear strain g = 0.05 if failure has not occurred; this reduces uncertainty for high shear‑elongation materials.
• Calculations and reporting:
  • In‑plane shear stress is calculated from instantaneous load and specimen cross section.
  • Shear strain is obtained as the sum of longitudinal and transverse strains (εx + εy).
  • Shear (chord) modulus is derived from shear stress and strain intervals (example points g' = 0.001 and g'' = 0.005 in the standard).
  • Minimum five specimens are required; results include mean values, standard deviation and 95% confidence intervals if requested.

Applications

This test method provides practical material properties for:

• Structural design and finite element input where accurate in‑plane shear properties are required.
• Comparative evaluation of laminate lay‑ups and resin/fibre combinations.
• Quality control and acceptance testing of production panels and prepregs.

The method is most effective for materials that fail in the expected shear‑dominated manner; caution is advised when interpreting ultimate shear values for high‑elongation systems.

Related Standards

• ISO 5893 - tensile test machine requirements
• ISO 291 - conditioning and testing atmospheres
• ISO 1268 / ISO 2818 - specimen and panel preparation guidance
• ISO 2602 - statistical interpretation and confidence intervals

For full procedural details, formulas and annex guidance on specimen preparation, refer to the complete EN ISO 14129:1997 text. The standard provides the required test geometry, data collection, calculation method and mandatory reporting items for traceable in‑plane shear characterization.

Standards Content (Sample)

SLOVENSKI STANDARD
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Fibre-reinforced plastic composites - Determination of the in-plane shear stress/shear
strain response, including the in-plane shear modulus and strength, by the +/- 45°
tension test method (ISO 14129:1997)
Faserverstärkte Kunststoffe - Zugversuch an 45°-Laminaten zur Bestimmung der
Schubspannungs/Schubverformungs-Kurve, des Schubmoduls und der Schubfestigkeit
in der Lagenebene (ISO 14129:1997)
Composites plastiques renforcés de fibres - Détermination de la réponse contrainte-
déformation en cisaillement plan, module et résistance compris, par essai de traction a
+/- 45° (ISO 14129:1997)
Ta slovenski standard je istoveten z: EN ISO 14129:1997
ICS:
83.120 2MDþDQLSROLPHUL Reinforced plastics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 14129
First edition
1997-12-15
Fibre-reinforced plastic composites —
Determination of the in-plane shear stress/
shear strain response, including the
in-plane shear modulus and strength,
by the – 45� tension test method
Composites plastiques renforcés de fibres — Détermination de la réponse
contrainte-déformation en cisaillement plan, module et résistance compris,
par essai de traction à – 45�
A
Reference number
ISO 14129:1997(E)
ISO 14129:1997(E)
Contents Page
1 Scope . 1
2 Normative references . 1
3 Principle . 2
4 Definitions . 2
5 Apparatus . 2
6 Test specimens . 4
Number of test specimens .
7 4
8 Conditioning . 5
9 Procedure . 5
10 Calculation and expression of results . 6
11 Precision . 7
12 Test report . 7
Annex
A Specimen preparation . 8
©  ISO 1997
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet [e-mail]
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Printed in Switzerland
ii
©
ISO ISO 14129:1997(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.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 14129 was prepared by Technical Committee
ISO/TC 61, Plastics, Subcommittee SC 13, Composites and reinforcement
fibres.
Annex A forms an integral part of this International Standard.
iii
©
ISO 14129:1997(E) ISO
Introduction
This International Standard covers all current and future fibre-reinforced
plastic composites which fail in the required manner. Harmonisation with
the new tensile standard, ISO 527-5:1997, Plastics — Determination of
tensile properties — Part 5: Test conditions for unidirectional fibre-
reinforced plastic composites, has been achieved where relevant (e.g.
document format, specimen size and related strains for modulus
measurement).
The test is acceptable for modulus but there is concern over its use for the
ultimate shear strength for high shear-elongation materials due to the high
strain at failure with only a small further increase in load, fibre rotation and
associated temperature rise. Therefore, the stress at a maximum shear
strain of 5 % or less is used as the failure criterion. This failure criterion is
also used in ASTM D 3518 (1995).
iv
©
INTERNATIONAL STANDARD  ISO ISO 14129:1997(E)
Fibre-reinforced plastic composites — Determination of the
in-plane shear stress/shear strain response, including the in-plane
shear modulus and strength, by the – 45� tension test method
1  Scope
1.1  This International Standard specifies a procedure for determining the in-plane shear stress/shear strain
response, including the in-plane shear modulus and shear strength, of fibre-reinforced plastic composites by the
– 45� tension test method.
1.2  The method is suitable for use with thermoset and thermoplastic matrix laminates made from unidirectional
layers and/or fabrics including unidirectional fabrics, with the fibres oriented at – 45� to the specimen axis, where the
lay-up is symmetrical and balanced about the specimen mid-plane.
NOTE —  The method is not suitable for coarse fabrics.
1.3  As the test has been shown to be sensitive to the number and distribution of layers, comparisons should be
undertaken using the same number of layers, which must be well distributed.
2  Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
ISO 291:1997, Plastics — Standard atmospheres for conditioning and testing.
ISO 1268:1974, Plastics — Preparation of glass fibre reinforced, resin bonded, low-pressure laminated plates or
1)
panels for test purposes.
ISO 2602:1980, Statistical interpretation of test results — Estimation of the mean — Confidence interval.
ISO 2818:1994, Plastics — Preparation of test specimens by machining.
ISO 5893:1993, Rubber and plastics test equipment — Tensile, flexural and compression types (constant rate of
traverse) — Description.
____________
1)  Under revision.
©
ISO
ISO 14129:1997(E)
3  Principle
A test specimen consisting of a strip of rectangular cross-section with the fibres oriented at – 45� to the specimen
axis is loaded in tension. To determine the shear modulus the strains parallel and perpendicular to the specimen
axis are measured. The test is terminated at g = 0,05 if failure (excluding premature failure at or within the grip)
has not occurred.
NOTE —  Although this test method can establish shear stress/shear strain response well into the nonlinear region, the
ultimate stress and strain values so obtained should be evaluated with the following caution. The material in the gauge section
of this specimen is not in a state of pure shear, as normal stress components are present, even in the rotated ply coordinate
system. It has been established that when a – 45� laminate is loaded in tension, normal stress components, though small,
generally decrease the calculated ultimate stress and strain values of the material below the actual capability of the material,
thus resulting in lower values of ultimate strength and strain than those obtained by more ideal methods, such as the tube
torsion test.
4  Definitions
For the purposes of this International Standard, the following definitions apply:
4.1  in-plane shear stress, t : The shear stress obtained by dividing the instantaneous load by twice the
specimen cross-sectional area.
It is expressed in megapascals (MPa).
4.2  in-plane shear strength, t : The maximum in the shear stress prior to or at termination of the test at
12M
g = 0,05.
It is expressed in megapascals (MPa).
4.3  shear strain, g : The sum total of strain in the direction parallel and perpendicular to the specimen axis, i.e.
(e - e ).
x y
NOTE —  e has an negative sign when e is positive.
y x
4.4  in-plane shear (chord) modulus, G : The shear stress difference (t ¢¢ - t ¢) divided by the corresponding
12 12 12
shear strain difference (g ¢¢ = 0,005 - g ¢ = 0,001) [see 10.3, equation (3)].
12 12
It is expressed in megapascals (MPa).
4.5  specimen coordinate axes: For the specimen shown in figure 1, the direction parallel to the specimen
longitudinal axis is the “x” direction and the direction perpendicular to it is the “y” direction. The fibres are oriented at
– 45� to these directions. The coordinate axes for a unidirectional reinforced composite material plate element are
shown in figure 2.
5  Apparatus
5.1  Test machine
5.1.1  General
The machine shall conform to ISO 5893 as appropriate to the requirements
...