EN ISO 21765:2021
(Main)Textiles - Determination of fabric deformability by forced mechanical distension (ISO 21765:2020)
Textiles - Determination of fabric deformability by forced mechanical distension (ISO 21765:2020)
This document specifies a method for the automatic determination of the deformability of textile fabrics, including continuous-fibre reinforcement textiles. This method is not applicable to resin impregnated fabrics.
The method is suitable for use with fabrics such as woven or knitted fabrics, nonwovens, non-crimp fabrics, fabrics made of glass rovings or untwisted carbon filament yarns intended for reinforced composite materials. When applying the method to multi-axial non-crimp fabrics, the evaluation of the fibre orientation and gaps only incorporates the uppermost layer.
The method can be used for fabrics treated with powder binder.
Textilien - Bestimmung der Verformbarkeit von Flächengebilden durch erzwungene Umformung (ISO 21765:2020)
Dieses Dokument legt ein Verfahren zur automatischen Bestimmung der Verformbarkeit von textilen Flächengebilden, einschließlich Verstärkungstextilien für endlosfaserverstärkte Textilien, fest. Dieses Verfahren ist nicht für harzimprägnierte Flächengebilde anzuwenden.
Das Verfahren ist geeignet für Flächengebilde wie Webstoffe oder Maschenware, Vliesstoffe, Gelege, Flächengebilde aus Glasrovings oder ungedrehten Kohlenstoff Filamentgarnen, die für verstärkte Werkstoff-Verbunde vorgesehen sind. Bei Anwendung des Verfahrens auf multiaxiale Gelege schließt die Auswertung der Faserorientierung und der Gaps nur die oberste Lage ein.
Das Verfahren kann für mit Pulverbinder behandelte Flächengebilde angewendet werden.
Textiles - Détermination de la déformabilité des étoffes par distension forcée mécaniquement (ISO 21765:2020)
Le présent document spécifie une méthode pour la détermination automatique de la déformabilité des étoffes textiles, y compris celle des textiles de renfort par fibres continues. Cette méthode n'est pas applicable aux étoffes imprégnées de résine.
La méthode est applicable aux étoffes telles que les étoffes tissées ou tricotées, les nontissés, les étoffes à base de fils sans embuvage, les étoffes constituées de mèches de verre ou les fils de filaments en carbone détordus destinés à des matériaux composites renforcés. Lors de l'application de la méthode à des étoffes à base de fils sans embuvage multiaxiales, l'évaluation de l'orientation des fibres et des espaces porte seulement sur la couche supérieure.
La méthode peut être utilisée pour des étoffes traitées avec un liant en poudre.
Tekstilije - Ugotavljanje deformabilnosti tkanine s prisilnim mehanskim raztezanjem (ISO 21765:2020)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 21765:2021
01-marec-2021
Tekstilije - Ugotavljanje deformabilnosti tkanine s prisilnim mehanskim
raztezanjem (ISO 21765:2020)
Textiles - Determination of fabric deformability by forced mechanical distension (ISO
21765:2020)Textilien - Automatische Bestimmung der Deformierbarkeit an Webstoffen und Gelegen
(ISO 21765:2020)Textiles - Détermination de la déformabilité des étoffes par distension forcée
mécaniquement (ISO 21765:2020)
Ta slovenski standard je istoveten z: EN ISO 21765:2021
ICS:
59.060.01 Tekstilna vlakna na splošno Textile fibres in general
SIST EN ISO 21765:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 21765:2021
EN ISO 21765
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2021
EUROPÄISCHE NORM
ICS 59.080.30
English Version
Textiles - Determination of fabric deformability by forced
mechanical distension (ISO 21765:2020)
Textiles - Détermination de la déformabilité des étoffes Textilien - Automatische Bestimmung der
par distension forcée mécaniquement (ISO Deformierbarkeit an Webstoffen und Gelegen (ISO
21765:2020) 21765:2020)This European Standard was approved by CEN on 7 December 2020.
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 21765:2021 E
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SIST EN ISO 21765:2021
EN ISO 21765:2021 (E)
Contents Page
European foreword ....................................................................................................................................................... 3
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EN ISO 21765:2021 (E)
European foreword
This document (EN ISO 21765:2021) has been prepared by Technical Committee ISO/TC 38 "Textiles"
in collaboration with Technical Committee CEN/TC 248 “Textiles and textile products” the secretariat of
which is held by BSI.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 July 2021, and conflicting national standards shall be
withdrawn at the latest by July 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.
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 21765:2020 has been approved by CEN as EN ISO 21765:2021 without any modification.
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SIST EN ISO 21765:2021
INTERNATIONAL ISO
STANDARD 21765
First edition
2020-12
Textiles — Determination of fabric
deformability by forced mechanical
distension
Textiles — Détermination de la déformabilité des étoffes par
distension forcée mécaniquement
Reference number
ISO 21765:2020(E)
ISO 2020
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SIST EN ISO 21765:2021
ISO 21765:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
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
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Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
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SIST EN ISO 21765:2021
ISO 21765:2020(E)
Contents Page
Foreword ..........................................................................................................................................................................................................................................v
Introduction ................................................................................................................................................................................................................................vi
1 Scope ................................................................................................................................................................................................................................. 1
2 Normative references ...................................................................................................................................................................................... 1
3 Terms and definitions ..................................................................................................................................................................................... 1
4 Principle ........................................................................................................................................................................................................................ 3
5 Apparatus ..................................................................................................................................................................................................................... 3
6 Test specimen .......................................................................................................................................................................................................... 5
7 Procedure..................................................................................................................................................................................................................... 6
7.1 Inserting the test specimen .......................................................................................................................................................... 6
7.2 Specifications of the test ................................................................................................................................................................. 6
7.2.1 Test parameters ................................................................................................................................................................ 6
7.2.2 Evaluation parameters................................................................................................................................................ 6
7.3 Test procedure ......................................................................................................................................................................................... 7
8 Calculation and specification of the results ............................................................................................................................. 7
8.1 Non-crimp fabric ................................................................................................................................................................................... 7
8.1.1 General...................................................................................................................................................................................... 7
8.1.2 Deformation force ........................................................................................................................................................... 8
8.1.3 Gap width ............................................................................................................................................................................... 8
8.1.4 Gap portion ........................................................................................................................................................................... 8
8.1.5 Gap shape ............................................................................................................................................................................... 8
8.1.6 Fibre-angle change ......................................................................................................................................................... 8
8.1.7 Undulation ............................................................................................................................................................................. 8
8.1.8 Loop formation .................................................................................................................................................................. 8
8.1.9 Waviness ................................................................................................................................................................................. 9
8.1.10 Out-of-roundness ............................................................................................................................................................ 9
8.2 Woven fabrics ........................................................................................................................................................................................... 9
8.2.1 Characteristic value names, symbols and units .................................................................................... 9
8.2.2 Deformation force ........................................................................................................................................................... 9
8.2.3 Gap portion ........................................................................................................................................................................... 9
8.2.4 Gap area ................................................................................................................................................................................10
8.2.5 Gap shape ............................................................................................................................................................................10
8.2.6 Fibre-angle change ......................................................................................................................................................10
8.2.7 Undulation ..........................................................................................................................................................................10
8.2.8 Shearing angle .................................................................................................................................................................10
8.2.9 Waviness ..............................................................................................................................................................................10
8.2.10 Out-of-roundness .........................................................................................................................................................10
8.2.11 Residual deformation ...............................................................................................................................................10
8.3 Knitted fabrics ......................................................................................................................................................................................11
8.3.1 Table with characteristic value names, symbols and units ......................................................11
8.3.2 Deformation force ........................................................................................................................................................11
8.3.3 Gap portion ........................................................................................................................................................................11
8.3.4 Gap area ................................................................................................................................................................................11
8.3.5 Gap shape ............................................................................................................................................................................11
8.3.6 Waviness ..............................................................................................................................................................................11
8.3.7 Out-of-roundness .........................................................................................................................................................11
8.3.8 Residual deformation ...............................................................................................................................................12
8.4 Nonwovens ..............................................................................................................................................................................................12
8.4.1 Table with characteristic value names, symbols and units ......................................................12
8.4.2 Deformation force ........................................................................................................................................................12
8.4.3 Anisotropy ..........................................................................................................................................................................12
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8.4.4 Thinning-out .....................................................................................................................................................................12
8.4.5 Waviness ..............................................................................................................................................................................12
8.4.6 Out-of-roundness .........................................................................................................................................................13
8.4.7 Residual deformation ...............................................................................................................................................13
8.5 Evaluation .................................................................................................................................................................................................13
9 Test report ................................................................................................................................................................................................................13
Annex A (informative) Example images .........................................................................................................................................................16
Annex B (informative) Statistical data .............................................................................................................................................................18
Bibliography .............................................................................................................................................................................................................................19
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SIST EN ISO 21765:2021
ISO 21765:2020(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 38, Textiles, Subcommittee SC 24,
Conditioning atmospheres and physical tests for textile fabrics, in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 248, Textiles and textile products,
in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
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.© ISO 2020 – All rights reserved v
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Introduction
The determination of the deformation characteristics is relevant for all production processes in which
flat textile fabrics (including reinforcement textiles) are formed into a three-dimensional shape. This
example is the case for upholstery applications or the majority of current liquid composite molding
(LCM) processes. Knowledge about the development of deformation effects such as changes in fibre
orientation, undulation, and gaps in the textile is crucial for the safe design of processes and components.
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SIST EN ISO 21765:2021
INTERNATIONAL STANDARD ISO 21765:2020(E)
Textiles — Determination of fabric deformability by forced
mechanical distension
1 Scope
This document specifies a method for the automatic determination of the deformability of textile fabrics,
including continuous-fibre reinforcement textiles. This method is not applicable to resin impregnated
fabrics.The method is suitable for use with fabrics such as woven or knitted fabrics, nonwovens, non-crimp
fabrics, fabrics made of glass rovings or untwisted carbon filament yarns intended for reinforced
composite materials. When applying the method to multi-axial non-crimp fabrics, the evaluation of the
fibre orientation and gaps only incorporates the uppermost layer.The method can be used for fabrics treated with powder binder.
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 139, Textiles — Standard atmospheres for conditioning and testing3 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
reinforcement textile
fabric whose fibres are used to absorb and transfer the mechanical loads within a fibre-reinforced
composite material3.2
deformability
conformability for forced three-dimensional deformation
3.3
specimen plane
plane which is defined by the inserted undeformed test specimen
3.4
specimen holder
device consisting of a retaining ring and a ring-shaped fitting body that retains the test specimen
during deformation with a settable, evenly distributed pressure© ISO 2020 – All rights reserved 1
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3.5
deformation body
rotationally symmetrical body that deforms the test specimen centrally out of the specimen plane (3.3)
in a vertical upward direction3.6
deformation level
level with specified height to which the deformation body (3.5) elevates out of the specimen plane (3.3)
3.7deformation force
resulting force acting vertically on the deformation body (3.5) that arises during deformation
3.8fibre orientation
orientation of the fibres or filaments of the test specimen, determined in the textile plane using image
processing3.8.1
fibre-angle change
change of the global fibre orientation (3.8), determined using image processing
3.8.2
undulation
local change of the fibre orientation (3.8), determined using image processing
3.9
gap
open area between adjacent yarns, determined using image processing
EXAMPLE Non-crimp fabric gap, woven/knitted fabric gap.
3.10
waviness
continuous deformation over a certain region (>2 cm ) diverging from the textile plane, determined
using laser triangulation3.11
loop formation
deformation of individual yarns out of the textile plane, determined using laser triangulation
3.12out-of-roundness
deviation of the contour of the test specimen from a circular shape of equal area, determined using
image processing3.13
overall image
image recorded with the overall image camera for determining the contour of the test specimen
3.14detail image
image recorded by the detail camera with a minimum size of 1 000 mm and a minimum resolution of
64 pixels per millimetre3.15
non-crimp fabric
fabric made of several unidirectional layers of straight multifilament yarns which are bonded using an
auxiliary stitching thread or chemical meansNote 1 to entry: The expression “non-crimp fabric” is commonly used in the composite sector.
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3.16
residual deformation
continuous deformation of the sample diverging from the support surface, determined using laser
triangulation, measured after completion of the deformation and return of the deformation body (3.5)
below the support surface3.17
anisotropy
measure for the orientation of fibres in a nonwoven
Note 1 to entry: Values are between 1 (all fibres parallel to reference direction) and -1 (all fibres perpendicular to
reference direction), where 0 means complete isotropic (random) orientation3.18
thinning-out
tendency of a nonwoven fabric to build local thin places due to mechanical stress
4 PrincipleThis document specifies a method by which the textile fabric (including reinforcement textiles) to be
examined is forced to be deformed in a defined manner by a rotationally symmetrical deformation
body. Key figures and characteristic values that describe the textile to be examined regarding its
deformability are determined. For this, the mechanical resistance to a defined three-dimensional
deformation is measured and the resulting structural faults in the mesostructure and macrostructure
are examined using a digital image analysis system and laser triangulation.The test is carried out on a circular test specimen, which the testing instrument - by means of
a pneumatic specimen holder - holds in position with a defined force, which is equal around the
circumference of the retaining ring. During the test, the test specimen is incrementally deformed by a
deformation body acting from below and measured after each deformation level.The force acting vertically on the deformation body caused by the deformation is measured.
Several images of the original undeformed test specimen and later of the deformed test specimen are
recorded with a detail camera on a central circular path and evaluated. For non-crimp fabrics, the fibre
orientation as well as the occurrence of gaps between the yarns of the non-crimp fabric are determined.
For woven fabrics, the angle between the warp threads and weft threads as well as the area and
proportion of the woven fabric gaps are determined. For knitted fabrics, the area and proportion of
the gaps is determined. For nonwovens, the anisotropy and thinning-out are determined. The out-of-
roundness of the test specimen is additionally determined with an overall image camera.
Additionally, deformations out of the textile plane may be recorded on the rotating test specimen using
a laser triangulation sensor and output as numerical values for the waviness and the loop formation.
5 Apparatus5.1 Mechanical cutting equipment, to produce the circular test specimen from the laboratory sample.
NOTE Examples of suitable mechanical cutting equipment include punches and ultrasound cutters.
5.2 Deformability test apparatusTest device in which the test specimen is inserted and uniformly retained over the entire circumference
using a specimen holder, whereby the retaining pressure can be specified in the range of 0 MPa to
0,1 MPa (i.e. 1 bar). The test device has a rotation device for motor-driven rotation of the test specimen
at variable speed [maximum speed (10,0 ± 0,1) min ], a motor-driven vertically moving deformation
body [elevation 0,00 – (100,00 ± 0,01) mm], a force sensor (0 N to 500 N with an accuracy of ±0,5 %)
to record the vertical force acting on the deformation body, an overall image camera to record the top
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view of the entire test specimen, a detail camera to record detail images of the test specimen to detect
fine structural faults, as well as a laser triangulation sensor (sampling time shorter than 20 ms from
data acquisition to data storage) to record the deformations varying from the textile plane.
The deformation body features a spherical contact surface with a diameter of (100,0 ± 0,1) mm. This
deformation body can be black or white. The black deformation body is used to test light-coloured
materials and the white deformation body to test dark materials. The white deformation body can be
backlit.The equipment for retaining the test specimen and for defined deformation is shown in Figure 1.
Key1 test specimen
2 deformation body
3 support surface
4 retaining ring
5 fitting body
Figure 1 — Specimen holder and deformation body
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Key
1 detail camera
2 laser triangulation sensor
3 overall image camera
Figure 2 — Schematic diagram of the optical sensors
Figure 2 illustrates the arrangement of the optical sensors. It shows a detail camera with lighting, an
overall image camera for recording the complete test specimen, as well a laser triangulation sensor to
record the test specimen topograph...
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