1、A. E.C. M .A. STANDARD NORME A.E.C.M.A. A.E.C.M.A. NORM prEN 2378 Issue P 1 October 1988 DIT PAR LASSOCIATION EUROPENNE DES CONSTRUCTEURS DE MATRIEL AROSPATIAL 88, boulevard Malesherbes, 75008 PARIS -TEL. 45-63-82-85 UDC : Key words : ENGLISH VERSION Aerospace series Fibre reinforced plastics Determ
2、ination of water absorption by immersion in demineralised water Srie arospatiale Luft- und Raumfahrt Plastiques renforcs de fibres Dtermination de labsorption deau par immersion dans teau dminralise Faser-Verstrkte Kunststoffe Bestimmung der Wasseraufnahme durch Lagern in entmineralisiertem Wasser T
3、his .Aerospace Series pre-standard has been drawn up under the responsibility of AECMA (Association Europenne des inatia of tlie difksion parameters is never straightlorward an reqiitres complex ca.lculat2ons which cur: only be undertaken with relat.i.ve1.y poweriul computem regardless. of the mathe
4、matical model selected. For all thefie .reasons thris standZr confiries itself to layig down a simple test Eethod or which the tece pieces and the procedure are dezixiei! as precineLy s possible, so as to eliminate 9.s maiiy parameters as pcssible. The results of the tests performed accordirrg to th
5、is standard zre therefore adequate iu permit : - a comparison between two rnterials, - the determiIiation of dlffusion parmeters at a later date if required; the ctoice 02 thebe, which depends oit the mdel adopted, is left to che user. 2 References Test methods for the decerdnation c? the ealii cont
6、ent of voten textile glass fibre fabric prehpregnate - Aerospace series 6W 2331 1) Sh 2564 Aerospace series - Larbon fibre lamiGates - Test method FOT the determination OE the fibre iid resin f ractioiis ard porosity cc.r,tei.it: EN 2741 Aerospace serqs - Mon-netallic materials a- ?referred test tem
7、perrittires ii , - 1) In preparation AECMA PREN2378 88 m 40L23LL 000305Li 5 I , prEN 2378 Page 4 3 Principle To deternirie the water absorption curve over time by immersion of a test piece of specified shape in demineralised water at a given temperature. The absorption characteristics are thus obtai
8、ned at right angles to the plane of the layers. The square test piece is relatively thin so that the edge effect is disregarded. 4 Apparatus 4.1 Containers Glass beakers of a size suited to the number of test pieces. 4.2 temperature. Temperature-controlled vessel with which to keep the containers at
9、 the test 4.3 Thermometer of appropriate scale and accuracy. 4.4 Ventilated oven which can be set to the desired temperature - + 5C. 4.5 4.6 Desiccator containing silica gel or equivalent. Balance accurate to within 2 0.1 mg. 4.7 Stirrer. 5 Test piece 5.1 Using a diamond wheel prepare the test piece
10、 from a sheet of the material under test; the dimensions shall be as specified in figure 1. 5.2 Note down the particulars of the surface finish of the test piece (machining, mould.release agents,.). 5.3 Note down the direction of the fibres or of the warp of the fabric. 5.4 Take at least five identi
11、cal test pieces for each temperature and material. 0622XSP0188T5 b - 3 a (mn) Dimensions Figure 1 b e ( d mm) e _3 Unmachined surfaces Flachned edges 50 e 2 0,l prEN 2378 Page 5 L 50 e 2 0,l 1 3- I I All= surfaces machined I 50 f 0,l I 50 2 0,l I 1 ,+ 0,05 Note 1 : If the surfaces of the test piece
12、are not machined (only the edges are machined) the number of layers shall be calculated in such a way that the thickness of the laminate is as near to 1 mm as possible. Note 2 : In all cases the spread of the thicknesses of test pieces shall be such that : e max. - e min. 3 MGcm-. 0622XSP0188T5 AECM
13、A PREN2378 88 LOL23LL 0003056 9 M deconpsition prciducts froir, the rnaterinl e If :it: hug:, the bath shall be reiiewed. 6.2 Yest tempercture it is pxferable to select: .;lie following t tureo, once a check Ilas been i!iade, so thst he temperature selected is not too close to t1:e t-mperaturc ct wh
14、ich the c2nia chaiiges to its vi-treous state : (23 - $. 1) OC if Gther temperatures are used they sfiail preferzbly be selected from ER 2744, a temperztxre tolerance of 2 1 C tieing permitted. They shd1 be recc-rded in the test report. The torci immers:i.on time is not fixed, but depends on the rii
15、eterid temperatuxti, etc. Noxtheless j.n.teniediate rnesuremen.tc shall Le iI:;ken at the following ilmersion i:iiI?!c?S : a) 1, 2, 4, 8, 16, 24, 48, 96, 168 h. 1:) 3 4, 6, 8, 16, 26, 52 weeks. c) 1,5 -3 2 1- 3 -a 4 - 5 years. G .4 Ccnditiciiiing the tent pieces Place the test pieces it1 the oven sr
16、: nt (70 i- I 2) “C until a corirt.ant mass is obcairied. :.CI co this, clteck weiglilir;gs shall he made at regiilar intervn.5 and thE gscnph inc1ucc.U in the test report. Notn down the mss W which represents .?lie last weighhg of che test piece to the i-ieaest 0,1 mg and thei place the test piece
17、fi; the desiccator. o 6.5 PreparinK the iinniersion bath use at ieast. It mi per cifi of total test piece surface area. When the test p2.eces are of th same conposition it is poccibe CG put severd. into the szm coiitciixter provide6 they do not touch each other. 0622XSPC7ECTT BEST COPY AVAILABE I AE
18、CMA PREN2378 88 M LOL231L 0003058 2 prEN 2378 Page 8 7.2 Plot the absorption curve (figure 2) as a function of /t for each test piece. Figure 2 If the dimensions of the test pieces meet the requirements of clause 5 and the sampling times are identical, plot the average absorption curve P (t) obtaine
19、d by plotting the average value of water absorption at the specified temperature as a function of fi: M N = the total number of test pieces. 7.3 Measurement of the absorption rate o( This is the slope at the origin of the absorption curve P expressed as a function o E where = fi. 7.4 Limit value for
20、 water content, M 00 This measurement shall only be made if it is evident that the water content really does reach a stable limit when the immersion time exceeds a value which depends on the product tested and the immersion temperature. 0622XSP0188T5 7.5 Further analyses It is not within the scope o
21、f this standard to specify the type of calculations to be made or the choice of model to use. Nonetheless laboratories wishing to calculate the diffusion parameters may consult the references (see annex). 8 Test report The test report shall contain a reference to this standard and include : 8.1 A fu
22、ll description of the naterial or prcduct tested : a) Preparation method b) Moulding cycle, including a diagram of : - moulding pressure, - partial vacuum applied, - curing temperature. c) Fibre content measured to EN 2331 (glass) and EM 2564 (carbon) d) Arrangement of the layers. 8.2 The dimensions
23、 of each test piece measured to within 0.01 nim. 8.3 The surface finish (machining, mou1.d release agent, .,.). 8.4 The number of test pieces. 8.5 The total conditioning time and temperature if different from those specified in 6.3 and 6.3. 8.6 The drying curve. 8.7 The total immersion time and temp
24、erature. 8.8 The lighting conditions. 8.9 8.10 The bsorptioii rate a( for each test piece. The immersion curve for each test piece and/or the mean absorption curve. prEN 2378 13.11. The absorpciori limit M if Sppropriare. 8.12 Any devhtion froni this standard and any iiicideit 1iibI.e to have affect
25、ed the results. 8.13 For each set of results (8.10 arid 8.11) an?. each temperuture (8,5), determine : .- the a,rithuietic neu of each parnracter, - the standard. deviation for each paramter : t s v z- N - 1 where 1 X = the finding X = the arithnetic meaii N = the tota number of test pieces. i - o u
26、 2 LX s P o 7 8 8T 5 _ AECMA- PREN2378 &- References - LANGKUIR - TYPE EODEL POR ANOPIALOUS MOISTURE DIFFUSION IN COMPOSITE RESINS HARRIS G. CARTER et alias J. of Composite Materials Vol. 12 - April 1978 - p. 118 - MOISTURE ABSORPTION AND DESORPTION OF COMPOSITE FATERIALS CHI-HUNG CHEN AND G.S. SPRINGER J. of Composite Materials Vol. 10 - January 1976 - p. 2 - LE MODELE DE LANGMUIR APPLIQUE A LA DIFFUSION DEAU DAHS LES MATERIAUX COMPOSITES TYPE CARBONE-EPOXY J.N. DEIJAS - JNC3 PARIS 09/82 pp. 89.96. o 0622XSP0188T5
