1、BRITISH STANDARD AEROSPACE SERIES BS EN 2374:1991 Specification for Glass fibre reinforcing mouldings and sandwich composites Production of test panels This European Standard EN 2374:1991 has the status of a British StandardBSEN 2374:1991 This British Standard was published under the authority ofthe
2、 Standards Board and comesinto effect on 28 June 1991 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference ACE/64 Draft for comment 89/79895 DC ISBN 0 580 19783 2 Cooperating organizations The European Committee for Standardization, under whose supervisio
3、n this European Standard was prepared, comprises the national standards organizations of the following Western European countries. Austria Oesterreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk Standardiseringsraad Finland Suomen Standardisoimisliito, r.y. France As
4、sociation franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland Ireland National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxemburg Inspection du Travail et
5、des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Espaola de Normalizacin y Certificacin Sweden Standardiseringskommissionen i Sverige Switzerland Association suisse de normalisation United Kingdom B
6、ritish Standards Institution Amendments issued since publication Amd. No. Date CommentsBSEN 2374:1991 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii Foreword 2 Text of EN 2374 3 National appendix NA (informative) Inside back cover National appendix NB (
7、informative) Inside back coverBSEN 2374:1991 ii BSI 12-1999 National foreword This British Standard has been prepared under the direction of the Aerospace Standards Policy Committee and is the English language version of EN2374 “Aerospace series Glass fibre reinforcing mouldings and sandwich composi
8、tes Production of test panels” published by the European Committee forStandardization (CEN). EN 2374 was produced as a result of international discussion in which the UK took an active part. A British Standard does not purport to include all the necessary provisions of a contract. Users of British S
9、tandards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN title page, pages 2 to 12, an inside back cover a
10、nd a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 2374 April 1991 UDC: 678.067.5-41:620.1:629.7 Descriptors: Aircr
11、aft industry, composite materials, reinforcing materials, laminates, laminated plates, glass cloth, manufacturing, characteristics, verification English version Aerospace series Glass fibre reinforced mouldings and sandwich composites Production of test panels Srie arospatiale Matriaux stratifis ren
12、forcs de fibres de verre et matriaux composites sandwich Prparation des panneaux dessais Luft- und Raumfahrt Glasfaserverstarkte Formstoffe und Kernverbunde Herstellen von Prfplatten This European Standard was approved by CEN on 28 March 1991. CEN members are bound to comply with the CEN/CENELEC Int
13、ernal 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 Central Secretariat or to any CEN memb
14、er. 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 Central Secretariat has the same status as the official versions. CEN members
15、 are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxemburg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches K
16、omitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels CEN 1991 Copyright reserved to all CEN members Ref. No. EN 2374:1991 EEN 2374:1991 BSI 12-1999 2 Foreword This European Standard has been prepared by the European Association of Aerospace Manufacturers (AECMA). After inquirie
17、s and votes carried out in accordance with the rules of this Association, this Standard has successively received the approval of the National Associations and the Official Services of the member countries of AECMA, prior to its presentation to CEN. According to the Common CEN/CENELEC Rules, the fol
18、lowing countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxemburg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Contents Page Foreword 2 1 Scope and field of application 3 2
19、 References 3 3 Type of fabrication 3 4 Equipment and apparatus 3 5 Tooling 3 6 Fabrication of laminate test panels 5 7 Fabrication of sandwich composite test panels 9 8 Fabrication of test panels for establishing the adhesive properties 10 9 Sampling 10 10 Test report 11 Figure 1 Press mould type 1
20、 4 Figure 2 Press mould type 2 4 Figure 3 Relationship between the glass content b v(volume-%) and the glass content b (mass-%) 6 Figure 4 Removal of the air bubbles and excess resin mix 7 Figure 5 Assembly for autoclave fabrication 9EN 2374:1991 BSI 12-1999 3 1 Scope and field of application This s
21、tandard describes the production of laminate and sandwich composite test panels from glass fibre fabric and resin mixes. Test specimens, which are specified for the determination of the characteristics of the glass fibre reinforced mouldings, for the verification of the properties of their component
22、s or for the verification of the adhesive and sandwich composite properties, are taken from the test panel in accordance with the relevant test standard. This standard is not applicable to the production of test panels from unidirectional glass fibre fabric and resin mixes. 2 References EN 2090, Aer
23、ospace series Aluminium alloy 2024-T3 Clad sheets and strips 0,4 u a u 6 mm 1) . EN 2334, Aerospace series Pickling of aluminium alloys in chromic acid 2) . EN 2514, Aerospace series Aluminium alloy 5052-H191 Honeycomb core 2) . EN 2743, Aerospace series Glass reinforced plastics Standard atmosphere
24、s for conditioning and testing 2) . 3 Type of fabrication 3.1 Type A Glass fibre fabric is impregnated with liquid resin mix and made into test panels in a press mould under the influence of pressure and temperature in accordance with the resin manufacturers processing instructions. 3.2 Type B Preim
25、pregnated glass fibre fabric (prepreg) is made into test panels under the influence of pressure and temperature in accordance with the manufacturers processing instructions. 3.3 Type C Glass fibre fabric is impregnated with liquid resin mix and made into test panels at room or elevated temperature w
26、ithout application of pressure in accordance with the resin manufacturers processing instructions. 4 Equipment and apparatus For types A and B, a hydraulic or mechanical press, an autoclave or equipment for vacuum bag fabrication is required. The equipment shall be fitted with a continuously variabl
27、e temperature and pressure control, which allows the prescribed values to be kept constant over the entire cure time. Provided there are no other agreements with the material supplier, the equipment shall be suitable for maintaining the temperature with an accuracy of 5 C and the press pressure with
28、 an accuracy of 5%. When a press is used, it shall be ensured that the press mould described in clause5 can be accommodated and that the closure rate for the last two millimetres of the closure travel does not exceed5mm/min. The equipment shall be fitted with suitable measuring devices for monitorin
29、g the fabrication parameters temperature, time and pressure. In autoclave or vacuum bag fabrication, a vacuum indicator shall also be available. In vacuum bag fabrication, it shall be ensured that the vacuum pump can maintain a reduced pressure of at least70kPa in the bag during the entire cure time
30、. Provided there are no different agreements with the material supplier, the production of the test panels is to be carried out in a light, well ventilated room at15 C to30 C and a relative humidity of30% to75%. 5 Tooling 5.1 Press moulds Press moulds according to Figure 1 and Figure 2 are used for
31、the production of test panels in a press. The choice of the press mould is to be made according to the material to be processed and the purpose of the test. The press moulds shall satisfy the following requirements: a) length and breadth of the pressing areas of the press mould shall be large enough
32、 to allow the manufacture of test panels from150mm 150mmto400mm 400mm. b) the moulding surfaces (surfaces designed for shaping the test panels) of the press mould should be hardened, polished and, if possible, hard chromium plated. 1) Published as AECMA standard at the date of publication of the pre
33、sent standard. 2) In preparation at the date of publication of the present standard.EN 2374:1991 4 BSI 12-1999 c) the lower moulding surface shall have a mark, which is reproduced on the test panel on pressing, in order to make the lower side of the test panel identifiable after the pressing procedu
34、re. The mark on the test panel shall not have a deleterious effect on the subsequent tests (seefirst note page4). d) the temperature over the entire moulding surface of the press mould shall not deviate locally by more than 3 C from the specified value e.g.measured by means of a thermocouple. e) the
35、 press mould type 1 consists of the elements shown in Figure 1. The height of the frame shall be large enough to provide a moulding cavity in which the glass fibre fabric impregnated with the resin mix can be inserted in one operation. f) the mould type 2 consists of the elements shown in Figure 2.
36、The plates shall be plane and parallel and are guided only at the four corners (open press mould). By placing spacers in the region of the guides, it is possible to mould to stops if required, i.e.a specific thickness of the test panel can be set. NOTEThe properties of the upper and lower faces of a
37、 pressed test panel are not exactly the same. As a result of the time span, which is necessary for putting the laminate in place and the closure process, the lower face of the test panel is heated longer and possibly also subjected to a higher temperature than the upper face. In the standards concer
38、ned, therefore, it is to be stipulated, if necessary, for which surface of the test panels the results shall be valid. Figure 1 Press mould type 1 Figure 2 Press mould type 2EN 2374:1991 BSI 12-1999 5 5.2 Tools for autoclave and vacuum bag fabrication For the fabrication of the laminate test panels,
39、 a pressure-tight base plate for the assembly, cover plate and various ancillaries, such as release films, sealing tape etc., are needed. For the fabrication of sandwich composite test panels, a rigid frame is also required, which shall be adjusted so that it takes up the forces acting laterally on
40、the sandwich composite structure in this fabrication process. 5.3 Tools for hand lay-up of laminate For the production of test panels in accordance with method C, a plane fixed support, approx.500mm 500mm in size and a cover (e.g.of glass) of the same size, are required, as well as spacers which can
41、 be inserted between the support and cover plate. NOTEAir bubbles can be detected easily if the support is either dark coloured or translucent and illuminated from below. 6 Fabrication of laminate test panels 6.1 Preparation 6.1.1 Pretreatment Unless otherwise specified, a pretreatment of the semifi
42、nished products shall be carried out for at least2h in the standard atmosphere in accordance with EN2743. 6.1.1.1 Glass fibre fabric A sufficient number of plies of glass fibre fabric for the fabrication of the test panel, seeclause6.1.2, is cut to size and dried in air for1h at80 C. Then the plies
43、are immediately stacked flat upon one another in a desiccator, where they shall be allowed to cool to room temperature. The drying can be omitted if the glass fibre fabric plies are kept in the standard atmosphere in accordance with EN2743, for at least48h before processing. 6.1.1.2 Preimpregnated g
44、lass fibre fabric Preimpregnated glass fibre fabric products, which have to be stored at temperature lower than room temperature, shall be air-tight packed then be brought to room temperature in a polyethylene bag so that no moisture pick-up can take place. The time required for the equilibration of
45、 temperature depends on the amount, but it shall not be less than4h. The time required is to be stated in the report. 6.1.2 Number of plies of glass fibre fabric for types A and C The number of plies of glass fibre fabric needed for a specific laminate thickness and a specific glass content can be c
46、alculated according to the following formula: in which: The number of plies of glass fibre fabric determined by this formula is to be rounded up or down in such a way that the test panel complies with the glass content in accordance with subclause6.1.5 and also the thickness requirement specified in
47、 the test standard. 6.1.3 Resin mixes 6.1.3.1 The resin mixes shall be produced and processed in accordance with the resin manufacturers processing instructions. 6.1.3.2 The amount m RMof the resin mix theoretically required is calculated according to the following formula: in which: The theoretical
48、ly determined amount m RMis to be increased by a least20% for the laminating process in practice to ensure a sufficient resine flow. 6.1.4 Number of plies of preimpregnated glass fibre fabric for type B The number of plies of glass fibre fabric necessary for a specific laminate thickness and a speci
49、fic glass content can be calculated according to the formula given in subclause6.1.2. For a sufficient resin flow, the glass content of the prepreg minus1% is used for b (glass content in mass-%) in the formula. n = number of plies of glass fibre fabric s = thickness of the test laminate, in mm m GL = mass per unit area of the glass fibre fabric product, in g/m 2 GL = density of the glass fibre fabric product, in g/cm 3 RM = density of the resin mix, in g/cm 3 b = glass content of the te
