SIST EN 4866:2021
(Main)Aerospace series - Definitions of imperfections and defects in organic matrix composite materials
Aerospace series - Definitions of imperfections and defects in organic matrix composite materials
This document provides a list of terms with their definitions illustrated by typical photographs, in order
to define a common vocabulary on the imperfections and damage that may occur during the
manufacture of organic matrix composite materials (which will be called “resin” in this document).
Some types of damage may also be encountered in use.
This document is restricted to their definitions and does not give any acceptance criteria. The word
“imperfection” will be preferred to the word “defect”, although the word “defect” might be usually used.
Defect acceptance criteria to be discussed between the user and customer and documented
appropriately between the two parties.
Luft- und Raumfahrt - Definitionen von Unvollkommenheiten und Defekten in der organischen Matrix Kompositmaterialien
Dieses Dokument enthält eine Liste von Begriffen mit Definitionen, die durch repräsentative Fotos illustriert werden, um einheitliche Begriffe für die Unvollkommenheiten und Schäden zu definieren, die bei der Herstellung von Produkten aus Verbundwerkstoffen mit Polymermatrix auftreten können (die in diesem Dokument als „Harz“ bezeichnet werden). Einige beschriebene Arten von Schäden können auch durch die Verwendung verursacht werden.
Dieses Dokument ist auf die Begriffserklärung beschränkt und enthält keine Abnahmekriterien. Das Wort „Unvollkommenheit“ wird dem Wort „Defekt“ vorgezogen, obwohl üblicherweise das Wort „Defekt“ verwendet werden kann. Die Fehlerabnahmekriterien sind zwischen Anwender und Kunde zu besprechen und entsprechend zu dokumentieren.
Série aérospatiale - Définitions des imperfections et défauts dans les matériaux composites à matrice organique
Aeronavtika - Definicije napak poškodb v organskih matričnih kompozitnih materialih
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 4866:2021
01-september-2021
Aeronavtika - Definicije napak poškodb v organskih matričnih kompozitnih
materialih
Aerospace series - Definitions of imperfections and defects in organic matrix composite
materials
Luft- und Raumfahrt - Definitionen von Unvollkommenheiten und Defekten in der
organischen Matrix Kompositmaterialien
Série aérospatiale - Définitions des imperfections et défauts dans les matériaux
composites à matrice organique
Ta slovenski standard je istoveten z: EN 4866:2021
ICS:
49.025.99 Drugi materiali Other materials
SIST EN 4866:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 4866:2021
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SIST EN 4866:2021
EN 4866
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2021
EUROPÄISCHE NORM
ICS
English Version
Aerospace series - Definitions of imperfections and defects
in organic matrix composite materials
Série aérospatiale - Définitions des imperfections et Luft- und Raumfahrt - Definitionen von
défauts dans les matériaux composites à matrice Unvollkommenheiten und Defekten in der organischen
organique Matrix Kompositmaterialien
This European Standard was approved by CEN on 19 August 2019.
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 4866:2021 E
worldwide for CEN national Members.
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SIST EN 4866:2021
EN 4866:2021 (E)
Contents Page
European foreword . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
3.1 General. 6
3.2 Bonding imperfections . 7
3.3 Presence of foreign substance . 8
3.4 Surface imperfections . 8
3.5 Cavities. 10
3.6 Fibres arrangement imperfection . 10
3.7 Imperfection specific to sandwiches. 11
3.8 Stitching imperfections . 12
3.9 Damage . 13
3.10 Other . 14
Annex A (informative) List of definitions and figures . 16
Annex B (informative) Pictures of bonding imperfections . 18
B.1 Absence of adhesive . 18
B.2 Absence of contact . 18
B.3 Adhesive joint colour heterogeneity. 18
B.4 Adhesive rupture . 19
B.5 Debonding . 19
B.6 Excessive adhesive bead . 19
B.7 Insufficient adhesion . 19
B.8 Junction imperfection . 20
B.9 Lack of adhesive . 20
Annex C (informative) Pictures of presence of foreign substances . 21
C.1 Foreign object. 21
C.2 Inclusion . 22
C.3 Pollution . 23
Annex D (informative) Pictures of surface imperfections. 24
D.1 Fern . 24
D.2 Flaking . 25
D.3 Wrinkle . 26
D.4 Imprint . 27
D.5 Indentation (dent/punching) . 27
D.6 Line flash . 28
D.7 Marbling . 28
D.8 Nick . 29
D.9 Pill . 29
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SIST EN 4866:2021
EN 4866:2021 (E)
D.10 Projection . 30
D.11 Resin flash . 30
D.12 Scratch . 31
D.13 Surface porosities . 31
Annex E (informative) Pictures of cavities . 33
E.1 Insufficient impregnation/dry area. 33
E.2 Porosities . 34
E.3 Voids . 34
Annex F (informative) Pictures of fibres arrangement imperfections . 35
F.1 Bird eyes . 35
F.2 Gap/overlap . 35
F.3 Off-centring . 36
F.4 Ply misorientation . 36
F.5 Resin accumulation . 36
F.6 Undulation. 38
Annex G (informative) Pictures of imperfections specific to sandwiches . 39
G.1 Accidental filling of honeycomb cells . 39
G.2 Core crushing (honeycomb or foam) . 39
G.3 Cut honeycomb . 40
G.4 Deformed honeycomb cells . 41
G.5 Edge filling imperfections . 41
G.6 Insufficient meniscus on honeycomb . 42
G.7 Lack of densification . 43
G.8 Separation of the honeycomb nodal joints . 43
G.9 Slope deformation (chamfer) . 44
G.10 Telegraphing . 45
Annex H (informative) Pictures of stitching imperfections . 46
H.1 Incorrect stitching depth . 46
H.2 Loop . 46
H.3 Missing stitching . 46
H.4 Non-conforming spacing . 46
H.5 Non-conforming angle . 46
Annex I (informative) Pictures of damages . 47
I.1 Burn . 47
I.2 Crack . 47
I.3 Cut ply . 48
I.4 Decohesion . 48
I.5 Delamination . 49
I.6 Microcrack . 50
I.7 Perforation . 50
I.8 Tearing-off of the material . 51
I.9 Whitening of the resin . 51
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EN 4688:2021 (E)
Annex J (informative) Pictures of other imperfections . 52
J.1 Excessive resin flow . 52
J.2 Feather duster . 52
J.3 Geometry imperfection . 52
J.4 Non-conforming number of plies . 52
J.5 Non-conforming stacking sequence . 53
J.6 Non-conforming thickness . 53
J.7 Pinching . 53
Bibliography . 54
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SIST EN 4866:2021
EN 4866:2021 (E)
European foreword
This document (EN 4866:2021) has been prepared by the Aerospace and Defence Industries
Association of Europe — Standardization (ASD-STAN).
After enquiries and votes carried out in accordance with the rules of this Association, this
document has received the approval of the National Associations and the Official Services of the
member countries of ASD, prior to its presentation to CEN.
This document shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by December 2021, and conflicting national standards shall be
withdrawn at the latest by December 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 document: 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.
5
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SIST EN 4866:2021
EN 4688:2021 (E)
1 Scope
This document provides a list of terms with their definitions illustrated by typical photographs, in order
to define a common vocabulary on the imperfections and damage that may occur during the
manufacture of organic matrix composite materials (which will be called “resin” in this document).
Some types of damage may also be encountered in use.
This document is restricted to their definitions and does not give any acceptance criteria. The word
“imperfection” will be preferred to the word “defect”, although the word “defect” might be usually used.
Defect acceptance criteria to be discussed between the user and customer and documented
appropriately between the two parties.
2 Normative references
There are no normative references in this document.
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 https://www.electropedia.org/
3.1 General
3.1.1
damage
damage corresponds to degradation of the resin and/or the fibres caused by mechanical, thermal or
environmental stresses
3.1.2
defect
imperfection or damage which exceeds the part acceptance criterion
3.1.3
imperfection
particularity encountered in composite materials that may result from the manufacturing process
and/or the conditions of use
Note 1 to entry: Detection may be carried out visually or by using laboratory equipment.
3.1.4
indication
information given by non-destructive test means and which may correspond to an imperfection
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EN 4866:2021 (E)
3.2 Bonding imperfections
See also EN ISO 10365.
3.2.1
absence of adhesive
absence of adhesive with respect to the part definition
Note 1 to entry: See Figure B.1.
3.2.2
absence of contact
presence of the required adhesive on one or both faces of the assembly, but with no contact
Note 1 to entry: Encountered in case of poor matching.
Note 2 to entry: See Figure B.2.
3.2.3
adhesive joint colour heterogeneity
possible imperfections when using two-component adhesives of different colours, and caused by
incomplete mixing of the components (visible in particular in the adhesive bead)
3.2.4
adhesive rupture
total or partial separation of a bonding interface without rupture of neither the substrate nor the
adhesive
Note 1 to entry: As opposed to cohesive rupture (characterized by a rupture within the substrate or the
adhesive).
Note 2 to entry: See Figure B.3 and Figure B.4.
3.2.5
debonding
separation of two items as a result of adhesive or cohesive failure in the adhesive layer
3.2.6
excessive adhesive bead
localised adhesive surplus on the edge of a joint plane
3.2.7
insufficient adhesion
localised insufficient adhesion between two materials (substrate, adhesive, primer, etc.) characterised
by insufficient mechanical strength of the interface
3.2.8
junction imperfection
incorrect positioning of one part with respect to the other during bonding
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SIST EN 4866:2021
EN 4688:2021 (E)
3.2.9
lack of adhesive
local lack of adhesive (insufficient quantity or poor distribution) with respect to the part definition
Note 1 to entry: See Figure B.5.
3.3 Presence of foreign substance
3.3.1
foreign object
presence of any solid (non-metallic) particle, which is not part of raw material formulation
3.3.2
inclusion
metallic foreign object
Note 1 to entry: See Figure C.3 and Figure C.4.
3.3.3
pollution
presence of liquid or powder substance, which is not part of raw material formulation
Note 1 to entry: See Figure C.5 and Figure C.6.
3.4 Surface imperfections
3.4.1
fern
cluster of localised areas of insufficient resin on the surface, having the appearance of a fern leaf
Note 1 to entry: Fern is a special case of surface porosities.
Note 2 to entry: See Figure D.1 and Figure D.2.
3.4.2
flaking
local tearing-off of material (see 3.9.8) of millimetric dimensions from the surface layer of a composite
(flake detached or not) often localised on the edge of a part or of a hole
Note 1 to entry: See Figure D.3, Figure D.4 and Figure D.5.
3.4.3
wrinkle
fold of the fibres out of plane affecting one or more layers
Note 1 to entry: See Figure D.6, Figure D.7 and Figure D.8.
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SIST EN 4866:2021
EN 4866:2021 (E)
3.4.4
imprint
hollow mark on the surface of the part related to the production tooling (mould or environment
products)
Note 1 to entry: See Figure D.9.
3.4.5
indentation (dent/punching)
bump of material due to an impact on the part
Note 1 to entry: See Figure D.10.
3.4.6
line flash
line shaped accumulation of resin caused by an undulation close to the surface of the part
Note 1 to entry: See Figure D.11.
3.4.7
marbling
heterogeneity of the part’s colour or gloss
Note 1 to entry: See Figure D.12.
3.4.8
nick
cut opening onto the surface of the part, due to a mechanical action (tool), which could affect the fibres
Note 1 to entry: See Figure D.13 and Figure D.14.
3.4.9
pill
cluster of fibre residues
Note 1 to entry: See Figure D.15.
3.4.10
projection
mark in relief (or surface topology imperfection) on the surface of the part
Note 1 to entry: See Figure D.16.
3.4.11
resin flash
thin layer of pure resin extending over the part surface
Note 1 to entry: See Figure D.17.
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SIST EN 4866:2021
EN 4688:2021 (E)
3.4.12
scratch
thin surface mark due to a mechanical action, affecting only the resin
Note 1 to entry: See Figure D.18.
3.4.13
surface porosities
localized points of insufficient resin on the surface
Note 1 to entry: The term “crater” can be used in case of an isolated cavity opening onto the surface, of dimension
greater than a few tenths of a millimetre.
Note 2 to entry: See Figure D.19 and Figure D.20.
3.5 Cavities
3.5.1
insufficient impregnation/dry area
lack of impregnation of the fibres by the resin
Note 1 to entry: See Figure E.1 and Figure E.2.
3.5.2
porosities
randomly distributed spherical gas cavities
Note 1 to entry: See Figure E.3, Figure E.4, Figure E.5 and Figure E.6.
3.5.3
voids
cavity with a tubular shape or whatever shape, e.g. bridging, piping
Note 1 to entry: Bridging is a condition where plies span an internal feature thus creating a void.
3.6 Fibres arrangement imperfection
3.6.1
bird eyes
local separation of two adjacent tows
Note 1 to entry: See Figure F.1.
3.6.2
gap/overlap
ply not positioned edge to edge with respect to the adjacent ply, which generates an overlap or gap of
material
Note 1 to entry: The gaps and overlaps may be in the part definition.
Note 2 to entry: See Figure F.2 and Figure F.3.
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EN 4866:2021 (E)
3.6.3
off-centring
modification of the angle between the warp and the weft
Note 1 to entry: See Figure F.4.
3.6.4
ply misorientation
deviation of the fibres’ direction in a ply (unidirectional or fabric) compared to the theoretical definition
3.6.5
resin accumulation
surplus of a resin volume without fibre which could locally affect the Fibre Volume Ratio (FVR) and
geometry of the part
Note 1 to entry: See Figure F.5, Figure F.6 and Figure F.7.
3.6.6
undulation
waviness deformation of the fibres in or out of the plane
Note 1 to entry: See Figure F.8 and Figure F.9.
3.7 Imperfection specific to sandwiches
3.7.1
accidental filling of honeycomb cells
filling of one or more honeycomb cells by skin resin, adhesive or densification resin
Note 1 to entry: See Figure G.1.
3.7.2
core crushing (honeycomb or foam)
damage to the core resulting in a local reduction in its thickness or shape, possibly leading to buckling
of the honeycomb or deformation of the foam
Note 1 to entry: See Figure G.2 and Figure G.3.
3.7.3
cut honeycomb
cut in the honeycomb during the implementation process, by a sharp object
Note 1 to entry: See Figure G.4.
3.7.4
deformed honeycomb cells
sideways movement of the cell walls to produce one or several line(s) of distorted cells
Note 1 to entry: See Figure G.5 and Figure G.6.
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SIST EN 4866:2021
EN 4688:2021 (E)
3.7.5
edge filling imperfection
insufficient resin filling on the edge of a sandwich panel
Note 1 to entry: See Figure G.7.
3.7.6
insufficient meniscus on honeycomb
the adhesive or resin does not produce an effective fillet on the honeycomb (fillet not formed or badly
formed)
Note 1 to entry: See Figure G.8 and Figure G.9.
3.7.7
lack of densification
partial or total absence of the densification filling
Note 1 to entry: See Figure G.10.
3.7.8
separation of the honeycomb nodal joints
separation of adjacent honeycomb cells, possibly due to insufficient adhesive or incorrect bonding of
the sheets forming the honeycomb
Note 1 to entry: See Figure G.11.
3.7.9
slope deformation (chamfer)
difference in slope angle with respect to the definition, by crushing of the core or slipping of the
honeycomb
Note 1 to entry: This imperfection occurs mainly during the polymerisation phase.
Note 2 to entry: See Figure G.12 and Figure G.13.
3.7.10
telegraphing
collapse of the composite skin into the honeycomb cells
Note 1 to entry: See Figure G.14, Figure G.15 and Figure G.16.
3.8 Stitching imperfections
3.8.1
incorrect stitching depth
stitching depth does not conform with the definition
3.8.2
loop
thread pulled out of the weaving plane
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SIST EN 4866:2021
EN 4866:2021 (E)
3.8.3
missing stitch
absence of stitch throughout the part thickness compared to the definition pattern
Note 1 to entry: See Figure H.1.
3.8.4
non-conforming spacing
spacing between the stitches does not conform with the definition pattern
3.8.5
non-conforming stitching angle
stitching angle does not conform with the definition
3.9 Damage
3.9.1
burn
sign of local thermal decomposition causing a colour variation, perhaps blackening, and which could
damage the material
Note 1 to entry: See Figure I.1.
3.9.2
crack
rupture in the part thickness, with broken fibres, not crossing through the entire part
Note 1 to entry: See Figure I.2.
3.9.3
cut ply
accidental cut of the reinforcement, caused by a mechanical action
Note 1 to entry: See Figure I.3.
3.9.4
decohesion
fibre/resin separation
Note 1 to entry: See Figure I.4 and Figure I.5.
3.9.5
delamination
rupture
...
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