1、BS EN 2823:2017Aerospace series Fibrereinforced plastics Determination of the effect ofexposure to humid atmosphereon physical and mechanicalcharacteristicsBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS EN 2823:2017 BRITISH STANDARDNational forewordThis British S
2、tandard is the UK implementation of EN 2823:2017. The UK participation in its preparation was entrusted to TechnicalCommittee ACE/65, Non-metallic materials for aerospace purposes. A list of organizations represented on this committee can be obtained on request to its secretary.This publication does
3、 not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2017.Published by BSI Standards Limited 2017ISBN 978 0 580 96075 8 ICS 49.025.40Compliance with a British Standard cannot confer immunity from lega
4、l obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2017.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS EN 2823:2017EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 2823 March 2017 ICS 49.0
5、25.40 English Version Aerospace series - Fibre reinforced plastics - Determination of the effect of exposure to humid atmosphere on physical and mechanical characteristics Srie arospatiale - Plastiques renforcs de fibres - Dtermination de linfluence de lexposition latmosphre humide sur les caractris
6、tiques mcaniques et physiques Luft- und Raumfahrt - Faserverstrkte Kunststoffe - Ermittlung des Einflusses der Auslagerung in feuchtem Klima auf die mechanischen und physikalischen Eigenschaften This European Standard was approved by CEN on 6 February 2017. CEN members are bound to comply with the C
7、EN/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 C
8、entre 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
9、the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Neth
10、erlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2017 CE
11、N All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 2823:2017 EBS EN 2823:2017EN 2823:2017 (E) 2 Contents Page European foreword . 3 1 Scope . 4 2 Normative references . 4 3 Terms and definitions 4 4 Methodology 5 5 Apparatus 5 6 Specime
12、ns . 5 7 Procedure . 7 8 Expression of results 10 9 Designation . 11 10 Test report . 11 BS EN 2823:2017EN 2823:2017 (E) 3 European foreword This document (EN 2823:2017) has been prepared by the Aerospace and Defence Industries Association of Europe - Standardization (ASD-STAN). After enquiries and
13、votes carried out in accordance with the rules of this Association, this Standard 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 European Standard shall be given the status of a national standard
14、, either by publication of an identical text or by endorsement, at the latest by September 2017, and conflicting national standards shall be withdrawn at the latest by September 2017. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights
15、. CEN and/or CENELEC 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, Cyp
16、rus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and t
17、he United Kingdom. BS EN 2823:2017EN 2823:2017 (E) 4 1 Scope This European Standard specifies the method for determining the effect of exposure to a humid atmosphere on the physical and mechanical characteristics of fibre reinforced plastics. This standard applies to all laminates, whatever the natu
18、re of the reinforcement and organic matrix used, unless otherwise indicated in the material standard and/or technical specification. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated r
19、eferences, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 2743, Aerospace series Fibre reinforced plastics Standard procedures for conditioning prior to testing unaged materials EN 2744, Aerospace series No
20、n-metallic materials Preferred test temperatures EN 3615, Aerospace series Fibre reinforced plastics Determination of the conditions of exposure to humid atmosphere and moisture absorption 1)3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 “pi
21、lot“ specimens specimens intended to establish the exposure temperature required to achieve an equilibrium condition at the specified humidity level in a limited period of time 3.2 specimens “to be aged“ specimens intended to determine the mechanical and physical characteristics after exposure 3.3 “
22、traveller“ specimens specimens representative of specimens “to be aged“ which accompany these in the climatic chamber and are intended to monitor moisture absorption 3.4 equilibrium condition condition of the material at a specified hygrometry when it has reached constant mass 3.5 constant mass mass
23、 of the specimen obtained after several successive weighings carried out at regular intervals when the difference between weighings is less than a specified value 1) Published as ASD-STAN Prestandard at the date of publication of this standard by AeroSpace and Defence industries Association of Europ
24、e - Standardization (ASD-STAN) (www.asd-stan.org) BS EN 2823:2017EN 2823:2017 (E) 5 3.6 as-cured condition see EN 2743 4 Methodology The test results obtained with the specimens in the as-cured condition are compared with those obtained with specimens “to be aged“ after exposure to the specified hum
25、id atmosphere, in accordance with the following procedure: a) carry out the mechanical or physical test according to the appropriate standard on specimens in the as-cured condition (see EN 2743A); b) using pilot specimens determine the highest possible exposure temperature guaranteeing a behaviour o
26、f the material in conformity with Ficks law (reaching an equilibrium condition). This determination shall be carried out at least once for each case of fibre/resin/temperature combination; c) expose the specimens “to be aged“ to the specified hygrometry and to the temperature as determined above unt
27、il they reach the equilibrium condition. Traveller specimens shall be permanently subjected to the same exposure conditions; d) carry out the mechanical or physical tests according to the applicable standards. NOTE 1 In the preparation of this standard both Langmuir model and Ficks law were consider
28、ed. While acknowledging that Langmuir Models more exact, Ficks law will be used to define equilibrium conditions in composite materials. A temperature of 70 C is chosen as the initial verification temperature in order to achieve a reasonable rate of moisture pick-up. If the pilot specimens results s
29、uggest a significant deviation from Flicks law then a lower temperature should be selected. 5 Apparatus 5.1 Climatic chamber capable of keeping the specified temperature to within 1 C and relative humidity to within 3 %. 5.2 Desiccator. 5.3 Balance accurate to within 0,1 mg. 5.4 Air circulating oven
30、 capable of keeping the specified temperature to within 5 C. 5.5 Clean and dry absorbent cloth or filter paper. 5.6 Sealed container: metallized polythene bag or airtight metal or glass enclosure. 6 Specimens All the aspects of the manufacturing process (in particular the surface finish) influence t
31、he test results. BS EN 2823:2017EN 2823:2017 (E) 6 6.1 Pilot specimens The panels intended to make up the pilot specimens shall be symmetrically arranged in layers: unidirectional preimpregnates: unidirectional (0) or crossed (0/90) lay-up; fabrics: all plies warpwise in the same direction. The dime
32、nsions of the pilot specimens shall be in conformity with Figure 1 and Table 1. Figure 1 Table 1 Dimensions in millimetres 75 1 b 75 1 a the lowest possible 6.2 Specimens “to be aged“ (specimens for mechanical and physical tests) The shape, dimensions and manufacturing procedure for the specimens ar
33、e specified in the material standard or test method. They shall be in their final form, for example, machined, drilled, tabbed, etc. 6.3 Traveller specimens A minimum of three traveller specimens, taken from the same panel as the specimens “to be aged“, but without tabs, holes, etc. shall be used. T
34、he traveller specimens shall be rectangular or square, their length and width equal to or greater than 25 mm and their mass greater than 1,5 g. The quality of the faces and edges shall be identical to that of the ageing specimens. BS EN 2823:2017EN 2823:2017 (E) 7 7 Procedure 7.1 Conditioning before
35、 exposure Specimens to be aged shall not undergo any special conditioning, a condition of equilibrium being the only criterion sought. 7.2 Exposure conditions 7.2.1 The humidity level shall be specified. Standard condition: %8515+Optional: %9515+7.2.2 Determination of exposure temperature It shall b
36、e determined on the pilot specimens according to the following procedure: expose a pilot specimen to the exposure temperature of (70 2) C; check that the condition of equilibrium has been reached (see 7.2.3) at this temperature; if this is not the case, expose a new pilot specimen to a lower tempera
37、ture chosen from EN 2744; check that the condition of equilibrium has been reached (see 7.2.3) at this new temperature; if this is not the case, redo the procedure until a temperature is determined whereby the condition of equilibrium is reached. NOTE 1 If the condition of equilibrium is reached at
38、70 C, a higher exposure temperature may be sought, chosen from EN 2744. NOTE 2 This operation may be replaced by a continuous weighing (thermobalance type setup) of the pilot specimen in a humid atmosphere. 7.2.3 Determination of the condition of equilibrium The total period of exposure for all spec
39、imens shall be continued until they reach the equilibrium condition. Constant mass is achieved for test specimens of a thickness of (2 0,2) mm when the difference between three successive weighings carried out at an interval of 168 h on traveller specimens (see figure 2) and in conformity with the f
40、ormula below: jjjMMM 2 5 10-4where Mj represents the mean weights of the travellers specimens at the time tj. BS EN 2823:2017EN 2823:2017 (E) 8 Figure 2 If the exposure temperature is less than 70 C or if the thickness differs from (2 0,2) mm, the time interval between two successive weighings to de
41、termine constant mass shall be obtained by trials; with the value of the difference remaining as above. 7.3 Exposure to humid atmosphere Place the traveller specimens and specimens to be aged in the climatic chamber. The contact between: the specimens themselves; the specimens and the walls of the c
42、hamber and (or) specimen supports; shall be point contact in order to ensure maximum exposure. 7.4 Monitoring humidity absorption 7.4.1 Remove the traveller specimens from the climatic chamber and wipe them to remove any condensation with the cloth or paper (see 5.5). 7.4.2 Allow them to cool to roo
43、m temperature in a sealed container to reduce moisture loss to a minimum. 7.4.3 Immediately weigh them to the nearest 0,1 mg. M1is the mean of the weighings of the traveller specimens in the equilibrium condition (see 7.2.3). 7.5 Physical and mechanical tests after exposure 7.5.1 Testing at ambient
44、temperature Remove the specimens “to be aged“ from the climatic chamber and follow the same procedure as in 7.4.1 and 7.4.2. The specimens may be maintained for a maximum of 72 h in a sealed container. The physical or mechanical test shall be carried out according to the relevant standard within the
45、 30 min following removal from the sealed contained. BS EN 2823:2017EN 2823:2017 (E) 9 7.5.2 Testing at temperatures other than ambient Follow the instructions given in 7.5.1. Place the specimen in the test fixture which has been maintained at the specified temperature. In order to limit moisture lo
46、ss but ensure thermal equilibrium, the period between placing the specimen in the fixture and completion of the test shall be as short as possible, while ensuring that the specimen test zone is at the specified temperature. If the test duration permits, this period shall be: less than 15 min, for te
47、mperatures ranging from ambient to 50 C; less than 5 min, for carbon fibre based specimens of a thickness ranging from 1 mm to 2 mm and for temperatures ranging from 50 C to 100 C. For other temperatures, dimensions and materials, if the tests duration does not allow the above mentioned requirements
48、 to be met, this period shall be determined by prior test designed to check that the specified temperature is reached at all points subject to an acceptable moisture loss. If it is not possible to achieve thermal equilibrium with an acceptable moisture loss, use a fixture or chamber which minimises
49、the moisture loss of the specimen during testing. This is essential for lengthy tests such as fatigue or creep, for example. The actual change in moisture level when measuring the characteristic to be determined, shall be verified with a traveller specimen or calculated according to an agreed mathematical model. Any change shall be recorded to enable interpretation of the test results. 7.6 Amount of moisture absorbed by traveller specimens Dry the traveller specimens in an oven u
