INTERNATIONAL STANDARD IS0 14126:1999
TECHNICAL CORRIGENDUM 1
Published 2001-07-15
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEX(QYHAP0nHAFI OPTAHkl3AUMFI fl0 CTAWPTH3AUHH ORGANISATION INTERNATIONALE DE NORMALISATION
Fibre-reinforced plastic composites - Determination of
compressive properties in the in-plane direction
TECHNICAL CORRIGENDUM 1
Composites plastiques renforcés de fibres - Détermination des caractéristiques en compression dans le plan
RECTIFICA TIF TECHNIQUE 1
Technical Corrigendum 1 to International Standard IS0 14126:1999 was prepared by Technical Committee
ISOTTC 61, Plastics, Subcommittee SC 13, Composites and reinforcement fibres.
Page 1, subclause 1.4
Replace the second paragraph by the following text:
“IS0 604 (see the bibliography) applies to bulk compounds having fibres shorter than 7,5 mm. This is generally
the case with materials intended for injection moulding.”
~~
ICs 83.120 Ref. No. IS0 14126:1999/Cor.I:2001(E)
O IS0 2001 -All rights reserved
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STD=ISO 3432b-ENGL 3779 E 4853703 0794035 887 E
INTERNATIONAL
STANDARD
IS0
141 26
First edition
1999-09-01
Fibre-reinforced plastic composites -
Determination of compressive properties in
the in-plane direction
Composites plastiques renforcés de fibres - Détermination des
caractéristiques en compression dans le plan
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part of these IS0 documents may be reproduced in any form, electronic retrieval system
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22 734 1 O 79), IHS or the IS0 Licensor's members.
Reference number
IS0 14126:19!39(E)
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STD=ISO IrlbZb-ENGL 1999 4851903 079403b 715
IS0 14126:1999(E)
Contents
1 scope ........................................................................................................................................................................ 1
2 Normative references .............................................................................................................................................. 2
3 Definitions ................................................................................................................................................................ 2
4 Principle .................................................................................................................................................................... 3
5 Apparatus ................................................................................................................................................................. 3
5.1 lest machine ......................................................................................................................................................... 3
5.1.1 General ................................................................................................................................................................ 3
5.1.2 Speed of testing ................................................................................................................................................. 4
5.1.3 Indication of load ............................................................................................................................................... 4
5.2 Strain measurement ............................................................................................................................................. 4
5.3 Micrometer ............................................................................................................................................................. 4
5.4 Loading fixtures .................................................................................................................................................... 4
5.4.1 General ................................................................................................................................................................ 4
5.4.2 Method 1 : shear loading ................................................................................................................................... 4
5.4.3 Method 2: end loading ....................................................................................................................................... 4
6 Test specimens ........................................................................................................................................................ 4
6.1 Shape and dimensions ......................................................................................................................................... 4
6.1.1 Type A specimen ............................................................................................................................................... 4
6.1.2 Type B specimen ............................................................................................................................................... 5
6.2 Preparation ............................................................................................................................................................ 5
6.2.1 General ................................................................................................................................................................ 5
6.2.2 End-tab material ................................................................................................................................................. 5
6.2.3 Application of end tabs ..................................................................................................................................... 5
Q IS0 1999
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Q IS0 IS0 14126:1999(E)
6.2.4 Machining the specimens ................................................................................................................................. 5
6.3 Checking ................................................................................................................................................................ 6
7 Number of test specimens ...................................................................................................................................... 6
8 Conditioning ............................................................................................................................................................. 6
9 Procedure ................................................................................................................................................................. 6
10 Expression of results ............................................................................................................................................ 7
11 Precision ................................................................................................................................................................. 8
12 lest report .............................................................................................................................................................. 8
Annex A (normative) Specimen preparation .......................................................................................................... 12
Annex B (informative) Compression fixtures for method 1 .................................................................................. 14
Annex C (informative) Compression fixtures for method 2 .................................................................................. 15
Annex D (informative) Euler buckling criteria ........................................................................................................ 17
Bibliography .............................................................................................................................................................. 18
iii
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IS0 141 26:1999(€) o IS0
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0
member bodies). The work of preparing International Standards is normally carried out through IS0 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. IS0 collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISOAEC Directives, Part 3.
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 IS0 14126 was prepared by ISOTTC 61, Plastics, Subcommittee SC 13, Composites and
reinforcement fibres.
This first edition cancels and replaces IS0 851 5:1991, which dealt only with glass-fibre-reinforced plastic
composites.
Annex A forms a normative part of this International Standard. Annexes B to D are for information only.
iv
8 IS0
STD*ISO L412b-ENGL 3999 4853903 0794039 424
IS0 14126:1999(E)
Introduction
This standard is based on IS0 8515, with the scope extended to include all fibre-reinforced plastic composites, such
as more recent composites based on carbon and aramid fibres, but retains the test conditions relevant for giass-
fibre-reinforced systems. Other source documents consulted include ASTM D 341 O (buckling criteria, larger
specimen width and longer gauge length), ASTM D 695 (modified version in SACMA SRMl), prEN 2850,
CRAG 400, DIN 65380 and JIS K 7076 (see bibliography).
Several different types of jig, different materials and different specimen sizes are covered by these source
documents. The table below presents examples, the specimen sizes being given as overall length x gauge length x
width x thickness, in millimetres.
IS0 8515 Celanese type End block
110 x 13 x 6,4 x 2 (GRW 120 x 20 x 10 x (3 to 10)
prEN 2850 Celanese type ASTM D 695 Revision includes a machined
(CFRP) 11ox l o x 1 0 x 2 8Ox5x12,5x2 specimen with co-cured tabs.
JIS K 7076 ASTM D 695 Celanese Il-rRI
(CFRP) 78 x 8 x 123 x 2 134 x 8 x 6,5x 2 108 x 8 x (6 to 123) x (1 to 2)
ASTM D 3410 Celanese I ìTRI
(all fibres) 140 x (25 to 12) x (12 or 25) x variable
(equationshables give required thickness for modulus, expected strength and gauge length)
140 x 12 x 6 x variable
DIN 65380 Celanese ITTRI
(all fibres) 112 x 8 x 6,35 x 2 112 x 8 x 6,35 x 2
CRAG 400
(all fibres) 11ox 10X10X2
Ce I an es e
SACMA SRM1
(all fibres)
ASTM D 695 (modified)
80,8 x 12,7 x 4,8 x [l (unidir.) or 3 (fabric)]
These test methods use aspect ratios (heightíthickness and heightlwidth) for the gauge area covering a range of
values, which appears undesirable in a test known to be susceptible to buckling failures. Also, new support jigs are
still being developed. This International Standard harmonizes and rationalizes the current situation by:
concentrating on the quality of the test by limiting the maximum bending-buckling strain allowable at failure
(¡.e. 10 % as recommended by ASTM - see also 5 % level in prEN 2850), so that it is possible to justify an
axial-load analysis;
allowing any design of jig to be used that meets this above requirement, using two methods of loading
(¡.e. shear and end loaded);
standardizing on two specimen designs, one principally for unidirectional material and one for other materials
(the chosen specimen can be used with either loading method);
adding an informative note as annex D, which was proposed by ASTM for harmonization purposes, and is
taken from ASTM D 3410 (in a modified form).
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~~
INTERNATIONAL STANDARD 8 IS0 IS0 141 26: 1999( E)
Fibre-reinforced plastic composites - Determination of
compressive properties in the in-plane direction
1 Scope
1.1 This International Standard specifies two methods for determining compressive properties, in directions parallel
to the plane of lamination, of fibre-reinforced plastic composites.
1.2 The compressive properties are of interest for specifications and quality-control purposes.
1.3 Two loading methods and two types of specimen are described. They are:
- Method 1: provides shear loading of the specimen (gauge length unsupported).
- Method 2: provides end Loading, or mixed loading, of the specimen (gauge length unsupported).
NOTE
shear through the tabs.
For tabbed specimens end-loaded using method 2, some load is transferred into the specimen gauge length by
- Type A specimen: rectangular cross-section, fixed thickness, end-tabbed.
- Type B specimen: rectangular cross-section, range of thicknesses, untabbed or end-tabbed (two sizes
available).
Any combination of test method and specimen may be used, provided that the requirements of subclause 9.8 are
satisfied and that the specimen is representative of the material under test. These alternative test conditions will not
necessarily give the same result.
The type A specimen is the preferred specimen for unidirectionally reinforced materials tested in the fibre direction.
For other materials, the type A or B specimen may be used. The type 82 specimen is preferred for mat, fabric and
other multidirectionally reinforced materials.
1.4 The methods are suitable for fibre-reinforced thermoplastic and thermosetting plastic composites.
Unreinforced and particle-filled plastics, as well as those reinforced with short fibres (less than 1 mm in length), are
covered by IS0 604 (see bibliography).
1.5 The methods are performed using specimens which may be machined from a test panel made in accordance
with IS0 1268 or equivalent methods, or from finished or semi-finished products.
1.6 The methods specify required dimensions for the specimen. Tests which are carried out on specimens of other
dimensions, or on specimens which are prepared under different conditions, may produce results which are not
comparable. Other factors, such as the speed of testing, the support fixture used and the condition of the
Specimens, can influence the results. Consequently, when comparative data are required, these factors must be
carefully controlled and recorded.
1.7 Fibre-reinforced plastics are usually anisotropic. It is therefore often useful to cut test specimens in at least the
two main directions of anisotropy, or in directions previously specified (for example a lengthwise direction
associated with the production process).
1
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IS0 141 26:1999(E) Q IS0
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of IS0 and IEC
maintain registers of currently valid International Standards.
IS0 291 :1997, Plastics - Standard atmospheres for conditioning and testing.
IS0 527-1 :1993, Plastics - Determination of tensile properties - Part I: General principles.
IS0 527-4: 1 997, Plastics - Determination of tensile properties - Part 4: Test conditions for isotropic and
orthotropic fibre-reinforced plastic composites.
IS0 1268:1974, Plastics - Preparation of glass fibre reinforced, resin bonded, low-pressure laminated plates or
panels for test purposes (under revision).
IS0 2602:1980, Statistical interpretation of test results - Estimation of the mean - Confidence interval.
IS0 3534-1 :1993, Statistics - Vocabulary and symbols - Part 1: Probability and general statistical terms.
IS0 5893:1993, Rubber and plastics test equipment - Tensile, flexural and compression types (constant rate of
traverse) - Description.
IS0 9353: 1 991, Glass-reinforced plastics - Preparation of plates with unidirectional reinforcements by bag
moulding.
3 Definitions
For the purpose of this International Standard, the following definitions apply:
3.1
compressive stress
CC
the compressive force experienced by the test specimen at any particular moment divided by the initial cross-
sectional area of the parallel-sided portion of the specimen
It is expressed in megapascals.
3.2
compressive strength
compressive failure stress
Oc,
the maximum compressive stress sustained by the specimen
It is expressed in megapascals.
3.3
compressive strain
E,
the ratio of the decrease in the distance between the gauge marks on the parallel-sided portion of the test specimen
(due to a compressive force) to the initial distance between the gauge marks
It is expressed as a dimensionless ratio or in percent.
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8 IS0
STD*ISO 1412b-ENGL 1999 4851903 079VOV2 T19
IS0 14126:1999(E)
3.4
compressive failure strain
&cM
the longitudinal compressive strain at the compressive failure stress
It is expressed as a dimensionless ratio or in percent.
3.5
modulus of elasticity in compression
chord modulus
the stress difference (d minus d) divided by the corresponding strain difference [EL1 (= 0,0025) minus d (= 0,0005)]
(see subclause 10.2)
It is expressed in megapascals.
E,
3.6
specimen coordinate axes
the coordinate axes for the material with the fibres preferentially aligned in one direction (see Figure 1)
The direction parallel to the fibre axes is defined as the "l''-direction and the direction perpendicular to the fibre axes
the "2"-direction. For other materials, the "l''-direction is normally defined in terms of a feature associated with the
production process, such as the long direction for a continuous-sheet process. The "2"-direction is again
perpendicular to the "1" direction.
Results for specimens cut parallel to the "1 "-direction are identified by the subscript