1、BRITISH STANDARD AEROSPACE SERIES Glass fibre reinforced plastics - Tensile test The European Standard EN 27471998 has the status of a British Standard ICs 49.025.40 BS EN 2747:1998 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW STD*BSI BS EN 2747-ENGL 1998 9 Lb24bb9 0732b117
2、 38T 9 direction of the Engineering Amd. No. Date Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 November 1998 BS EN 2747:1998 Text affected National foreword This British Standard is the English hguage version of EN 27471998. The UK partic
3、ipation in its preparation was entrusted to Technical Committee ACW64, Aerospace structural reinforced plastics, which has the responsibility to: - aid enquirers to understand the text; - present to the responsible internationfiuropean committee any enquiries on the intqretation, or proposals for ch
4、ange, and keep the UK interests informed - monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement internaonal or E
5、uropean publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the ne
6、cessary provisions of a contract. Users of British Standards 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, the EN title page,
7、pages 2 to 14, an inside back cover and a back cover. O BSI 1998 I I ISBN O 580 30716 6 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 2747 August 1998 ICs 49.025.40 Descriptors: Aircraft industry, reinforced plastics, glass reinforced plastics, tests, tension tests English version Aerospace s
8、eries - Glass fibre reinforced plastics - Tensile test Sde arospatiale - Plastiques renforcs au Vene textile - Essai de traction Luf- und Raumfahrt - Glasfaserverstrkte Kunststoffe - Zugversuch This European Standard was approved by CEN on 15 May 1998. CEN members are bound to comply with the CEWCEN
9、ELEC 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 Central Secretariat or to any
10、CEN member. This European Standard exists in three oficial versions (English, French, German). A version in any other language made by translation under the responsibllity of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN
11、members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy. Luxembourg, Netherlands, Noway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMiTEE FOR STANDARDIZATION COMITE EUROPkEN DE NORMALI
12、SATION EUROPISCHES KOMITEE FR NORMUNG Central Secretariat: nta de Stamart, 36 8-1050 BNSSCS (B 1998 CEN All rights of exploitation in any form and by any means reserved worklwide for CEN national Members. Ref. No. EN 2747:1998 E Page 2 EN 2747: 1998 Foreword This European Standard has been prepared
13、by the European Association of Aerospace Manufacturers (AECMA). After inquiries and 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 AECMA, prior to its presen
14、tation to CEN. 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 February 1999, and conflicting national standards shall be withdrawn at the latest by February 1999. According to the CEWCENELEC Inte
15、rnal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland
16、 and the United Kingdom. STD.BS1 BS EN 2797-ENGL 1998 D Lb24bb 0732b50 7Y 9 Page 3 EN 2747: 1998 1 scope This standard specifies a method for the determination of tensile properties of glass fibre reinforced plastics for aerospace applications. 2 Normative references This European Standard incorpora
17、tes by dated or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European
18、Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 2374 Aerospace series - Glass fibre reinforced mouldings and sandwich composites - Production of test panels EN 2489 EN 2743 EN 2823 Aerospace series -
19、 Fibre reinforced plastics - Determination of the action of liquid chemicals Aerospace series - Reinforced plastics - Standard atmospheres for conditioning and testing 1) Aerospace series - Fibre reinforced plastics - Test method for the determination of the effect of exposure to humid atmosphere on
20、 physical and mechanical characteristics 1) 3 Definitions For the purpose of this standard the following definitions apply: 3.1 Tensile stress Tensile load experienced by the specimen at any moment during the test, per initial unit cross sectional area within the free length. 3.2 Ultimate tensile st
21、rength Tensile stress at the moment failure occurs. 3.3 Strains Change in the distance between reference points in the specimen free length, produced by a tensile load and expressed with respect to the initial distance between these points. 3.4 Percentage strain to failure Increase in the distance b
22、etween reference points in the specimen free length, produced by a tensile load and expressed as a percentage of the initial distance between these points and measured at the moment of failure. 1) Published as AECMA Prestandard at the date of publication of this standard Page 4 EN 27471998 3.5 Modul
23、us of elasticity Quotient of the tensile stress and corresponding strain within the linear area. NOTE: It is the slope of the stresdstrain diagram obtained during the tensile test. If the limit of proportionality is exceeded or if there is no linear area, it is necessary to define: 3.5.1 Tangent mod
24、ulus Slope of the tangent at the origin of the stresdstrain diagram. 3.5.2 Slope of the straight line going through the origin of the stress/strain diagram and the point in this diagram which corresponds to a strain of x %. Secant modulus at x % 4 Principle The method consists of the measurement of
25、the longitudinal strain in the material, in relation to the load applied, during a tensile test camed out at a constant speed until failure occurs. This method enables the following tensile properties to be determined: - uitimate tensile strength; - modulus of elasticity; - percentage strain to fail
26、ure. 5 Apparatus 5.1 Te8t machine Constant speed tensile machine with: a) The grips shall be designed such that the axis of the specimen is aligned at all times with the direction of the applied load. This can be achieved, for example, by using centring pins within the grips. A fixed part with a sui
27、table grip and a mobile part with a second grip. b) A load measuring system of negligible inertia accurate to k 1 ?O in the load range used. The fixed and mobile parts shall be constructed such that during the test the total longitudinal defonnation of these parts does not exceed 1 Yo of the specime
28、n free length. This requirement applies for the whole of the load range used. Page 5 EN 2747:1998 7 - - E - - Recommended specimen types - E F Minimum total length 5.2 Extensometer Thermoplastics Then Type 1 Type 2 150 250 It shall enable determination of the distance between two reference marks sit
29、uated on the free length of the specimen at any time during the test. The extensometer used shall not damage the specimen nor cause failures at the attachment points. The extensometer of negligible inertia with regard to the test speed, shall give the strain to f 1 % of the measured value. The gauge
30、 lengths recommended are given in table 1. However, shorter distances may be used, as long as the above requirements are met. 7 * rn 5.3 Micrometer with 6 mm diameter flat faces and accurate to f 0,Ol mm. - W Width of ends 20 i 0,5 Semi-finished products 2 to 10 2 to 10 h 6 Specimens 6.1 Dimensions
31、- 2 to 10 The types of specimens are defined ,I table 1 and figures - - to 4. 2 to 3,5 Table 1 : Types of specimens 1 f 0,2 to 3 *0,2 - I I thickness 2 to 3,5 Test panels specimen according to EN 2374 I Of I 2 to 3,5 c I I B Freelength b Width of free length 60 I 0,5 - 10 i 0.5 25 I 0,5 50 D Distanc
32、e between tabs T Minimum length of tabs P Diameter of centring holes (drilling of holes optional) e Thickness of tabs Radius - - - - + 0.25 - 0,05 - - - - 2 60 Gauge length 50 I E Distance between grips I 115 i 5 1 170f5 Dimensions in millimetres Unidirectional thermosets iosets 25 I0,5 10 f 0,5 1 O
33、0 170f5 I 50f2 I - 0,05 - 0,05 2f0,2 1 0,5*0,1 I Page 6 EN 2747:1998 cg: Grips Flgure 1: Specimen type 1 al II I + F Figura 3: Specimen type 3 Page 7 EN 2747:1998 Holes P Q o hl - - -x ?b Q OS b Fibre orientation in test specimen I I c- F Figure 4: Specimen type 4 Page 8 EN 2747:1998 6.2 Specimens p
34、reparation For thermosets, the specimens shall be cut from panels made according to EN 2374. For thermoplastics use preferably compression moulded panels to obtain the specimens. The results from injection moulded specimens are mainly influenced by the orientation of the fibre. This manufacturing me
35、thod may be used, when other methods for manufacturing specimens are not possible. If the specimens are to be taken from finished components, they shall be taken preferably from flat areas or those with minimum curvature. Avoid reducing thicknesses through a machining operation. If the surfaces of t
36、he specimens have been machined, the results obtained will not be comparable to those obtained on non- machined specimens. The lay up of the laminate and subsequent machining shall be carried out in such a way that the orientation of the fibre in the test direction is achieved to within f 1 O. 6.3 C
37、ut out, from the material to be tested, a sheet with the length of the specimens and width to suit the required number. To form the tabs, cut out, preferably from a material with a modulus of elasticity that is lower than that of the material being tested, rectangular strip to conform to the require
38、ments of table 1 and figure 6. Preparation and application of tabs (recommendation) Fix the strips as follows (see figure 6): a) Abrade all the surfaces to be bonded with fine abrasive paper. b) Carefully clean these with an appropriate solvent. c) Use an adhesive (for example an epoxy adhesive) of
39、flexible type, with an elongation at failure greater than that of the material tested. d) Position the strips so that they are perfectly aligned at each end, parallel to one another and perpendicular to the longitudinal direction of the specimens. e) Maintain under pressure for a sufficient period o
40、f time. This assembly (panel and tabs) constitutes a blank ready for cutting into specimens. 6.4 Machining Avoid process conditions that cause the specimen to overheat. It is recommended that a cooling fluid be used. In this case make sure the specimen is wiped dry immediately after machining. Check
41、 that the edges of the specimen are free of defects. 6.4.1 Type 1 specimens It is desirable to machine specimens with an abrading wheel or mill, using a template. 6.4.2 Type 2,3 and 4 specimens Preferably use diamond or silicon carbide saws. 6.5 Number Minimum of five for each test direction. * x. r
42、n Page 9 EN 2747:1998 7 Procedure 7.1 Conditioning - EN 2743 for tests in the initial state; - EN 2489 for tests after immersion; - EN 2823 for tests after exposure to humid atmosphere. 7.2 Test atmosphere Unless otherwise specified, carry out the tests at (23 f 2) OC and (50 f 5) To relative humidi
43、ty. 7.3 Make three of width to I0,l mm and of thickness to f 0,02 mm, on the specimen centreline: Measurement of the dimensions of the test specimens - one at the centre, - the others at distance (0,5 i, - 5) mm from the centre. 7.4 Record the minimum and maximum values of width and thickness and ma
44、ke sure that they are within the tolerances given in table 1. Calculate the arithmetical mean of the widths band thicknesses h Recording and calculation of the widths and thicknesses 7.5 Test Place the specimen in the grips, taking care to align its axis with that of the test machine. When the centr
45、ing pins are used, good alignment is obtained by light tension on the specimen before clamping the grips together. Clamp uniformly and strongly to avoid any slipping of the specimen. Check and, if required, calibrate the extensometer. Fix it at the centre of the specimen. NOTE: If a tensile load has
46、 been applied during clamping in the grips, reduce this to zero before measuring strain. Apply a test speed of (2 I 0,2) mm/min and record the load as a function of elongation (Z= L - 4). STD-BSI BS EN 271i7-ENGL It998 = lb24bb9 0732b57 229 Page 10 EN 2747:1998 8 Expmssion of results 8.1 Ultlmate te
47、nsfle strength F 6-h o= where: u F b h is the ultimate tensile strength, in megapascals, is the maximum load, in newtons, is the initial average width of the specimen, in millimetres, is the initial average thickness of the specimen, in millimetres. Record the result to three significant figures. 8.
48、2 Percentage strain to failure 1oo.z; L, a= where: a Z; L, is the strain to failure, in per cent; is the increase in the distance between reference points measured at failure and expressed in millimetres; is the gauge length, in millimetres. Record the result to two significant figures. 8.3 Tangent
49、modulus where: 4 AF, L, b h U, is the tangent modulus, in megapascals; is the change in load, in newtons (see figure 5); is the gauge length, in millimetres; is the initial average width of the specimen, in millimetres; is the initial average thickness of the specimen, in millimetres; is the increase in the distance between reference points corresponding to the difference in load AF, expressed in millimetres. NOTE: It is suggested to determine the secant modulus at 0.1 % instead of the tangent modulus, when the latter cannot be determined and to take it as
