1、_ STD-BSI BS EN 2557-ENGL 1997 1b2qbbS Ob31014 bT1 BRITISH STANDARD AEROSPACE SERIES Carbon fibre preimpregnates - Determination of mass per unit area The European Standard EN 2557 : 1997 has the status of a British Standard ICs 49.025.40 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPY
2、RIGH LAW BS EN 2557 : 1997 STD-BSI BS EN 2557-ENGL 1997 = lb24bb9 Ob32025 538 M AmdNo. Date BS EN 2667 : 1997 Text affected Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee ACW64, Aerospace smcturai reinforced pMcs, upon w
3、hich the following bodies were represented: British Plastics Federation Ministry of Defence Society of British Aerospace Companies This British Standard, having been prepared under the direction of the meeting Sector Board, was pubshed under the authority of ie Standards Board and comes into effect
4、on 16 August 1997 O BSI 1997 The foilowing BSI references relate to the work on this standard Committee reference ACE/ - have their centres positioned along a straight line. See figure 1 for wide woven fabrics, figure 2 for narrow woven fabrics and figure 3 for unidirectional sheet or tape. 1) Publi
5、shed as AECMA Prestandard at the date of publication of this standard STD-BSI BS EN 2557-ENGL 1997 M 1bZLIbb9 Ob31021 831 W Page 4 EN 2557:1997 Dimensions in millimetres I I Weft yarn I I I I direction Figure 1 Example of positioning of specimens on woven carbon fibre fabrics sample across the width
6、 Dimensions in millimetres c Width of woven tabric - Figure 2 Example of positioning of specimens on woven carbon fibre fabric sample along an axis inclined at an angle as close as possible to the weft direction STD-BSI BS EN 2557-ENGL 1777 m Lb24bb7 Ob3LU22 778 m Page 5 EN 2557:1997 Figure 3 Exampl
7、e of positioning of specimens on carbon fibre unidirectional sheet or tape sample STDmBSI BS EN 2557-ENGL 1777 = Lb24bb7 Ob11023 b04 Page 6 EN 2557:1997 6 Procedure 6.1 Conditioning 6.1.1 The amount of preimpregnate required for testing shall be sampled and then conditioned in the test atmosphere (s
8、ee 6.2) for a minimum of 2 h, unless otherwise specified. Preimpregnates stored at ambient temperature 6.1.2 The preimpregnate, suitably packed in an airtight and solvent resistant bag to prevent moisture pick- up, shall be allowed to reach ambient temperature over a period of time depending on its
9、mass. This Preimpregnates stored below ambient temperature ;ie shall not be less than 8 h. When the material has reached ambient temperature, the amount required for testing shall be sampled and then conditioned in the test atmosphere (see 6.2) for a minimum of 2 h, unless otherwise specified. 6.2 A
10、tmosphere for testing EN 2743, condition class B. 6.3 Time interval between conditioning and testing After conditioning, the sample shall be maintained in the test atmosphere. Unless otherwise specified, tests shall be carried out within 6 h. 6.4 Tests Cut the specimens. Weigh each specimen with its
11、 protective films to the nearest milligram (m,). Remove the protective films and reweigh these to the nearest milligram (m21. 7 Expression of results M = (ml - m2) K wher? : M m, m2 K = 100 m-2. is the mass per unit area, in grams per square meter ; is the mass of the specimen plus protective films,
12、 in grams ; is the mass of the protective films, in grams ; - STD.BS1 BS EN 2557-ENGL 1777 W 1b24bb7 Ob3L02L 540 H Page 7 EN 2557:1997 8 Health and safety requirements It is the responsibility of the user of this standard to adopt appropriate health and safety precautions. 9 lest report It shall inc
13、lude the following : - number of this standard ; - all data ensuring the traceability of the material (trade mark, identification marking, date of receipt etc.) ; all information regarding the sampling procedure ; form and dimensions of specimen ; period of conditioning ; test atmosphere, for exampl
14、e temperature, relative humidity if these differ from 6.2 ; time interval between conditioning and testing (see 6.3) ; individual values and arithmetic mean of the mass per unit area ; any incident which may have affected the results. STD-BSI BS EN 2557-ENGL 1777 Lb2Libb7 Ob31025 q87 W BS EN 2667 :
15、1997 List of references see national foreword. * m * 0 BSI 1997 STD-BSI BS EN 2557-ENGL 1777 W LbZLibbS Ob3L02b 313 M BS EN 2557 : 1997 BSI 389 ChiswickHigh Road London w4 4AL BSI - British Standards Institution BSI is the independent national body responsible for preparing British Standards. It pre
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