Fibre-reinforced plastic composites — Standard qualification plan (SQP) for composite materials, including reduced qualification plan (RQP) and extended qualification plan (EQP) schemes

1.1 This document specifies a procedure for the initial qualification of composite materials in order to allow quality control, material selection and preliminary design to be undertaken. It provides a single procedure allowing quicker and lower cost qualification compared to multiple bi-lateral qualification against different bespoke user needs. This document focuses on developing B-basis design allowables. 1.2 The procedure comprises a standard qualification plan (SQP) that includes the minimum common test requirements for more highly anisotropic composite materials. Further test requirements are encompassed in an extended qualification plan (EQP), which includes options representing specific in-service features. A reduced qualification plan (RQP) scheme, using the same core structure of test plate preparation and test methods as the SQP, is available for less highly anisotropic and tending towards nominally isotropic composite materials. 1.3 The procedure is suitable for fibre-reinforced thermoset, and thermoplastic, based material systems intended for structural or semi-structural applications. Individual test method standards referred to in this document provide more details as to the classes and types of composite materials that are covered in each case. 1.4 Annexes A and B are included to support presentation of the data obtained in a consistent database and to provide statistical procedures for the determination of B-basis design allowables, respectively.

Composites plastiques renforcés de fibres — Plan de qualification normalisé (PQN) pour matériaux composites, y compris les programmes pour plan de qualification réduit (PQR) et plan de qualification étendu (PQE)

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Status
Published
Publication Date
11-Jul-2019
Current Stage
6060 - International Standard published
Due Date
06-Oct-2018
Completion Date
12-Jul-2019
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INTERNATIONAL ISO
STANDARD 20144
First edition
2019-07
Fibre-reinforced plastic composites —
Standard qualification plan (SQP) for
composite materials, including reduced
qualification plan (RQP) and extended
qualification plan (EQP) schemes
Composites plastiques renforcés de fibres — Plan de qualification
normalisé (PQN) pour matériaux composites, y compris les
programmes pour plan de qualification réduit (PQR) et plan de
qualification étendu (PQE)
Reference number
ISO 20144:2019(E)
©
ISO 2019

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ISO 20144:2019(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
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Phone: +41 22 749 01 11
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Email: copyright@iso.org
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Published in Switzerland
ii © ISO 2019 – All rights reserved

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ISO 20144:2019(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 3
4 Principle . 4
5 Test methods and specimen conditioning . 4
6 Test matrices and specimen sampling . 5
7 Apparatus . 6
8 Test plate preparation and specimen machining .11
9 Test requirements .11
9.1 Standard qualification plan .11
9.2 Extended qualification plan .11
9.3 Reduced qualification plan .11
10 Presentation of results — Standardized data sheets .11
11 Statistical analysis .12
12 Precision .12
13 Test report .14
Annex A (normative) Report sheets .15
Annex B (normative) Determination of statistical parameters.19
Bibliography .27
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ISO 20144:2019(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 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.
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 2019 – All rights reserved

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ISO 20144:2019(E)

Introduction
This document has been prepared to provide suppliers, designers, end-users and regulators of fibre-
reinforced plastic/composite materials, with an initial qualification framework aimed at reducing the
substantial costs involved in qualifying materials against different bespoke company specifications,
with varying degrees of commonality. Indeed, the cost associated with qualifying materials can prevent
the use of new materials in certain applications or even the development of new materials themselves.
In addition, designers and end-users often find that appropriate data for materials selection and
preliminary design are not readily available or comparable. Widespread use of this document for initial
qualification is intended to lead to a reduction in qualification costs and increased availability of reliable
and robust materials data across a wide range of sectors and applications. It provides for more detailed
qualification procedures, including calculation of B-basis design allowable, compared to ISO 10350-2.
Material suppliers are intended to adopt this procedure for obtaining the required data to support
initial material selection and qualification; and to supply the specified data, in the format given in
Annex A, at the same time as release of the material evaluated. This will greatly extend the availability
of consistent and comparable materials data based on agreed individual, international test methods to
support users, fabricators and regulators.
Validation has been undertaken for thermoset systems, which are currently the most abundant and
[1]
established matrix-based systems. However, it is accepted that the calculations, and therefore the
property data, can also be applied to similar thermoplastic matrix-based systems.
Therefore, thermoplastic matrix-based systems can also be covered by the document, providing the
underpinning test method’s technical aspects are met regarding failure mode etc.; with the exclusion of
property tests specifically designed for uncured thermoset materials, where indicated.
It is noted that, simultaneously, the underpinning test methods are themselves being reviewed
for application to a wider range of fibre formats and matrices. Validation data will be added for
thermoplastic matrix-based systems when international precision trials are conducted.
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INTERNATIONAL STANDARD ISO 20144:2019(E)
Fibre-reinforced plastic composites — Standard
qualification plan (SQP) for composite materials,
including reduced qualification plan (RQP) and extended
qualification plan (EQP) schemes
1 Scope
1.1 This document specifies a procedure for the initial qualification of composite materials in order
to allow quality control, material selection and preliminary design to be undertaken. It provides a single
procedure allowing quicker and lower cost qualification compared to multiple bi-lateral qualification
against different bespoke user needs. This document focuses on developing B-basis design allowables.
1.2 The procedure comprises a standard qualification plan (SQP) that includes the minimum common
test requirements for more highly anisotropic composite materials. Further test requirements are
encompassed in an extended qualification plan (EQP), which includes options representing specific in-
service features. A reduced qualification plan (RQP) scheme, using the same core structure of test plate
preparation and test methods as the SQP, is available for less highly anisotropic and tending towards
nominally isotropic composite materials.
1.3 The procedure is suitable for fibre-reinforced thermoset, and thermoplastic, based material
systems intended for structural or semi-structural applications. Individual test method standards
referred to in this document provide more details as to the classes and types of composite materials that
are covered in each case.
1.4 Annexes A and B are included to support presentation of the data obtained in a consistent database
and to provide statistical procedures for the determination of B-basis design allowables, respectively.
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 62, Plastics — Determination of water absorption
ISO 75-3, Plastics — Determination of temperature of deflection under load — Part 3: High-strength
thermosetting laminates and long-fibre-reinforced plastics
ISO 291, Plastics — Standard atmospheres for conditioning and testing
ISO 527-4, Plastics — Determination of tensile properties — Part 4: Test conditions for isotropic and
orthotropic fibre-reinforced plastic composites
ISO 527-5, Plastics — Determination of tensile properties — Part 5: Test conditions for unidirectional fibre-
reinforced plastic composites
ISO 1172, Textile-glass-reinforced plastics — Prepregs, moulding compounds and laminates —
Determination of the textile-glass and mineral-filler content — Calcination methods
ISO 1183 (all parts), Plastics — Methods for determining the density and relative density of non-
cellular plastic
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ISO 20144:2019(E)

ISO 1268 (all parts), Fibre-reinforced plastics — Methods of producing test plates
ISO 1675, Plastics — Liquid resins — Determination of density by the pyknometer method
ISO 2818, Plastics — Preparation of test specimens by machining
ISO 6603-2, Plastics — Determination of puncture impact behaviour of rigid plastics — Part 2: Instrumented
impact testing
ISO 6721-11, Plastics — Determination of dynamic mechanical properties — Part 11: Glass transition
temperature
ISO 9782, Plastics — Reinforced moulding compounds and prepregs — Determination of apparent volatile-
matter content
ISO 10119, Carbon fibre — Determination of density
ISO 10352, Fibre-reinforced plastics — Moulding compounds and prepregs — Determination of mass per
unit area
ISO 11357-1, Plastics — Differential scanning calorimetry (DSC) — Part 1: General principles Differential
scanning calorimetry (DSC) — Part 1: General principles
ISO 11357-2, Plastics — Differential scanning calorimetry (DSC) — Part 2: Determination of glass transition
temperature and glass transition step height
ISO 11359-2, Plastics — Thermomechanical analysis (TMA) — Part 2: Determination of coefficient of linear
thermal expansion and glass transition temperature
ISO 11667, Fibre-reinforced plastics — Moulding compounds and prepregs — Determination of resin,
reinforced-fibre and mineral-filler content — Dissolution methods
ISO 12815, Fibre-reinforced plastic composites — Determination of plain-pin bearing strength
ISO 12817, Fibre-reinforced plastic composites — Determination of open-hole compression strength
ISO 14125, Fibre-reinforced plastic composites — Determination of flexural properties
ISO 14126, Fibre-reinforced plastic composites — Determination of compressive properties in the in-plane
direction
ISO 14127, Carbon-fibre-reinforced composites — Determination of the resin, fibre and void contents
ISO 14129, Fibre-reinforced plastic composites — Determination of the in-plane shear stress/shear
strain response, including the in-plane shear modulus and strength, by the plus or minus 45 degree
tension test method
ISO 14130, Fibre-reinforced plastic composites — Determination of apparent interlaminar shear strength
by short-beam method
ISO 15024, Fibre-reinforced plastic composites — Determination of mode I interlaminar fracture toughness,
GIC, for unidirectionally reinforced materials
ISO 15034, Composites — Prepregs — Determination of resin flow
ISO 15040, Composites — Prepregs — Determination of gel time
ISO 15114, Fibre-reinforced plastic composites — Determination of the mode II fracture resistance for
unidirectionally reinforced materials using the calibrated end-loaded split (C-ELS) test and an effective
crack length approach
ISO 16012, Plastics — Determination of the linear dimensions of specimens
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ISO 20144:2019(E)

ISO 18352, Carbon-fibre-reinforced plastics — Determination of compression-after-impact properties at a
specified impact-energy level
EN 821-1, Advanced technical ceramics — Monolithic ceramics — Thermo-physical properties — Part 1:
Determination of thermal expansion
EN 2823, Aerospace series — Fibre reinforced plastics — Determination of the effect of exposure to humid
atmosphere on physical and mechanical characteristics
ASTM D5766, Fibre-reinforced plastic composites — Determination of the open-hole, tensile strength
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
preimpregnate
prepreg
material in thin sheets of tows, tape, fabric, or mat impregnated with resin ready to be moulded, and
cured if thermoset based
Note 1 to entry: It may be stored before use (normally refrigerated for thermoset based systems).
Note 2 to entry: Used as a generic term in this document to refer to an intermediate product requiring application
of pressure and/or heat to form the final product.
3.2
compound
intimate admixture of a polymer or polymers with other ingredients such as reinforcements, fillers,
plasticizers, catalysts and colorants ready to be formed, and cured if thermoset based
3.3
preform
dry fibre preform suitable for infiltration by the matrix, normally thermoset based, to provide the final
material
3.4
batch
quantity of material formed during the same process and having identical characteristics throughout
based on a single supply of fibres, matrices and other additives
3.5
manufacturing run
single manufacturing process for test plates run by a single operator at a single time
3.6
plate and specimen coordinate axes
1-axis (or direction) where the material contains a known axis of preferred fibre orientation (e.g.
dominant fibre direction for unidirectional prepregs)
Note 1 to entry: For materials prepared as test plates, the in-plane direction transverse to the 1-axis is defined
as the 2-axis. Where any direction of preferred orientation is not known, the 1-axis is taken as the production
direction of the composite or the reinforcement (e.g. warp directions for fabrics).
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ISO 20144:2019(E)

Note 2 to entry: For fully unidirectional materials, specimens cut parallel to the “1”-direction, results are
identified by the subscript “11” (e.g. E11). Similarly, for specimens cut parallel to the “2”-direction are identified
by the subscript “22” (e.g. E22). For multidirectional laminates, mats and fabrics, results are identified by
the subscripts “XX” and “YY” for specimens cut parallel to the X and Y directions respectively. The X, Y and Z
coordinate system for any material are equated to the “1”-, “2”- and “3”- directions.
Note 3 to entry: A scheme for designating multiple direction lay-ups is given in the ISO 1268-4:2005, Annex A.
Figure 1 — Unidirectional reinforced composite plate element showing orthogonal axes
3.7
A-basis design allowable
statistically-based material property with a 95 % lower confidence bound on the first percentile of a
specified population of measurements
Note 1 to entry: It is also a 95 % lower tolerance bound for the upper 99 % of a specified population.
3.8
B-basis design allowable
statistically-based material property with a 95 % lower confidence bound on the tenth percentile of a
specified population of measurements
Note 1 to entry: It is also a 95 % lower tolerance bound for the upper 90 % of a specified population.
4 Principle
To provide an initial “standard qualification plan" based on accepted international test methods,
in combination with specified material preparation and batch test requirements. The standard
qualification plan (SQP) provides a minimum data set for the initial materials release suitable for
material selection and preliminary design phases, using a B-basis design allowable. The SQP is suitable
for high quality /high anisotropy preimpregnates (prepregs). An RQP allows less highly anisotropic
materials to be more easily and quickly evaluated. The EQP provides test methods for coupon level
tests for assessing simulated service requirements, such as, resistance to strain-concentrations (e.g. a
hole) and simulated damage.
NOTE It is noted that for A-basis design allowables, the number of specimens is increased to the order of
100 times, using increased number of batches and/or manufacturing runs depending on the sensitivity of the
[2]
measured properties to these two factors .
5 Test methods and specimen conditioning
Tables 1 and 2 specify the properties, test methods/applicable standards and batches to be used in the
SQP/RQP. Table 3 provides the same information for the EQP. The full title of each standard is given in
Clause 2. In addition, Tables 2 and 3 give “non-room temperature” test conditions, including after hot
4 © ISO 2019 – All rights reserved

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ISO 20144:2019(E)

wet conditioning. These conditions can be adjusted for non-aerospace applications as agreed with end
users (see 9.3).
Specimens shall be conditioned according to ISO 291 for ambient/room temperature (RT) testing.
Testing at non-ambient temperatures or after hot/wet conditioning shall be conditioned according
to the relevant test method, the material specification or by agreement between supplier and user’s
requirements.
In the absence of this information, the standard values for aerospace applications shall be used.
[3]
NOTE Guidance on preferred non-ambient test temperatures to be used is given in ISO 3205 .
6 Test matrices and specimen sampling
The prescribed qualification test regime (using the test methods listed in Clause 5) is detailed in
Tables 1 to 3. Tables 1 to 3 set out the numbers of batches of specimens per test method and per test
condition. The test requirements in these standards shall be adhered to regarding scope, specimen size,
failure criteria, etc.
Specimens shall be prepared and tested from either 1 or 3 batches of material depending on the criticality
of the data (i.e. the importance of the data for use in design, material selection, etc.). Specimens shall
be taken from 3 batches of material in order for measured values to be as representative as possible
of the material being tested and these batches shall be taken from the production of the material
over an extended timescale. In addition, to account for the processing variability associated with test
plate/panel manufacture, two plates shall be fabricated from each material batch, using independent
manufacture processes. Five specimens shall be extracted per plate for each test method, giving a total
of 30 specimens per property for a particular test condition.
In a similar manner, those properties measured using only 1 batch of material shall be determined from
10 specimens prepared from 2 plates (prepared using independent manufacture processes) from the
single batch.
Some test methods specify less than 5 specimens, but for this document 5 specimens per plate shall
be used.
Specimen selection and traceability (as described above) is illustrated in Figure 2.
NOTE At least two independent manufacture processes are required to fabricate all 6 plates, i.e. one lay-up
and cure cycle (Manufacture A) for plates 1, 3 and 5; and one lay-up and cure cycle (Manufacture B) for plates 2, 4
and 6 for a conventional thermoset resin based pre-preg.
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ISO 20144:2019(E)

Figure 2 — Batch, plate and specimen traceability
7 Apparatus
The equipment used in the work shall have a valid calibrated certificate traceable to SI units for the
measurements made, as required by the relevant test method standard; or be shown to have been
calibrated immediately prior to the measurements being made using transfer devices traceable to SI
units.
6 © ISO 2019 – All rights reserved

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ISO 20144:2019(E)

© ISO 2019 – All rights reserved 7
Table 1 — Standard qualification plan — Constituent and composites properties — Batch requirements
No. of material batches
Property Standard Unit Test conditions and supplementary instructions
SQP
CONSTITUENT PROPERTIES
2
1 Mass per unit area ISO 10352 g/m 3
Fibre mass per
2
2 ISO 10352 g/m 3
unit area
Fibre and matrix
3 ISO 11667 % 3
volume fractions
a
4 Gel time ISO 15040 minutes 3 Not applicable to a thermoplastic matrix
% weight Not applicable to a thermoplastic matrix
a
5 Matrix flow ISO 15034 3
change
Glass transition Indicator of service temperature for thermoset matrices,
6 ISO 11357-2 °C 3
a
temperature but not applicable to thermoplastic matrices
Percentage of Not applicable to a thermoplastic matrix
7 ISO 9782 % 3
a
volatile content
Carbon fibre based, but usable for other fibres depending
3
8 Density of fibre ISO 10119 g/cm 3
on the method
Deflection tem- Guide to maximum service temperature
9 perature under ISO 75-3 °C 3
load
3
10 Density of matrix ISO 1675 g/cm 3
 COMPOSITE PROPERTIES
5
Coefficient of ISO 11359-2 only suitable for values greater than 10 %/°C
EN 821-1/
11 thermal expan- %/°C 1
ISO 11359-2
sion
Moisture up- Distilled water at 23 °C, report saturation value
12 ISO 62 % 1
take — ambient
Moisture up- Conditioning in 70 °C/85 % atmosphere, report satura-
13 EN 2823 % 1
take —hot/wet tion value
Glass transition Relevant to service temperature for thermoset matrices,
14 temperature by ISO 6721-11 °C 3 but not for thermoplastic matrices. Tg is taken as the
DMA inflection point of storage modulus vs temperature plot.
Final ply thick- Divide plate thickness by number of “ply” layers to obtain
15 ISO 16012 mm 3
ness a nominal “ply” thickness.
a
Test method not suitable for thermoplastic matrix.

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ISO 20144:2019(E)

8 © ISO 2019 – All rights reserved
Table 1 (continued)
No. of material batches
Property Standard Unit Test conditions and supplementary instructions
SQP
ISO 14127 – carbon-fibre based systems
Fibre, matrix
ISO 14127/
16 and void volume % 3 ISO 1172 – glass-fibre based systems
ISO 1172
percent
ISO 1183 to be used for the required density measurement
a
Test method not suitable for thermoplastic matrix.

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ISO 20144:2019(E)

© ISO 2019 – All rights reserved 9
Table 2 — Standard qualification plan — Composite mechanical properties — Batch requirements
Test condition
Test conditions and supplementary
Property Symbol Standard Unit DRY 70 °C/85 % RH
instructions
a a
−55°C RT 70 °C 125 °C RT 70 °C
σ MPa 1 3 1 1
Μt11
σ MPa 1 1 (1) (1)
Refer to standard for specimen
Μt22
dimensions and test details.
E GPa 1 3 1 1
t11
() = not required for balanced fabrics
E GPa 1 1 (1) (1)
t22 Unidirectional
ISO 527-5
ε % 1 3 1 1
Mt11
17 Tension
ε % 1 1 (1) (1)
Multidirectional
Mt22 ν normally calculated from the
21
ISO 527-4
following relationship for orthotropic
ν 1
12
materials:
ν 1
13
ν ν (E E )
21 = 12 22/ 11
ν
21
NOTE  v = μ in ISO 527
ν 1
23
σ MPa 1 3 1 3
Mc11
Refer to standard for specimen dimen-
σ MPa 1 (1) 1
Mc22
sions and test details. Type A, B and
1
ISO 14126
B specimens, testing by
GPa 1 3 1 3
2
Ec11
18 Compression
unidirectional, Method 1 (shear loading) or Method 2
E GPa 1 (1) 1
c22
multidirectional (end loading)
ε % 1 3 1 3
Mc11
(1) = not required for balanced fabrics
ε % 1 (1) 1
Mc22
τ MPa 1 3 1 1 1 1
M12
Shear ± 45°
19 γ ISO 14129 % 1 3 1 1 1 1
M12
tension
G GPa 1 3 1 1 1 1
12
Interlaminar τ MPa 1 3 1 3 1 3
M1
20 shear strength ISO 14130
τ MPa 1 1
M2
(ILSS)
σ MPa 3
Mf11
Refer to standard for specimen dimen-
σ MPa 3
Mf22
sions and test details. Provide details
21 Flexural E ISO 14125 MPa 3
f11
of which method used. Method A (3-
E MPa 3
point flexure) is the default method.
f22
G GPa 3
13

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10 © ISO 2019 – All rights reserved
Table 3 — Extended qualification plan — Composite mechanical properties — Batch requirements
Test condition
Test conditions and supplementary
Property Symbol Standard Unit DRY 70 °C/85 % RH
instructions
−55 °C RT 70 °C 125 °C RT 70 °C
Quasi-isotropic lay-up. N.B. K is a
OHT
dimensionless stress concentration factor
σ
OHT calculated using σ and the unnotched
OHT
22 Open hole tension ASTM D 5766 MPa 1(1) 3(1) 3(1)
tensile strength (using ISO 527-4 and
( )
K
OHT
determined from bracketed number of
batches)
Quasi-isotropic lay-up.
NOTE  K is a dimensionless stress
OHC
σ
OHC concentration factor calculated using σ
OHC
23 Open hole compression ISO 12817 MPa 1(1) 3(1)  3(1)
and the unnotched compressive strength
(K )
OHC
(using ISO 14126 and determined from
bracketed number of batches)
Quasi-isotropic lay-up, plain pin —
Plane-pin bearing
24 σ ISO 12815 MPa 1 3  3 unrestrained (i.e. no washer, nuts or
p
strength
applied torque)
F N
M
Quasi-isotropic lay-up.
l mm
M
Refer to standard for additional
25 Instrumented impact E ISO 6603-2 J 3  3
M information req
...

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