1、AECMA STANDARD NORME AECMA AECMA NORM Edition approved for publication Comments should be sent within six months after the date of publication to prEN 361 5 Edition P 2 November 1998 C7 Chairman ICs: PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Gulledelle 94 - 8-1200 BRUXELL
2、ES - Tel. (+32) 2 775 81 10 - Fax. (+32) 2 775 81 11 Supersedes issue P 1 May 1991 Descriptors: ENGLISH VERSION Aerospace series Fibre reinforced plastics Determination of the conditions of exposure to humid atmosphere and of moisture absortion Srie arospatiale Luft- und Raumfahrt Plastiques renforc
3、s de fibres Dtermination des conditions dexposition latmosphre humide et de labsorption dhumidit Faserverstrkte Kunststoffe Ermittlung der Auslagerungsbedingungen in feuchtem Klima und der Feuchteaufnahme This “Aerospace Series Prestandard has been drawn up under the responsibility of AECMA (The Eur
4、opean Association of Aerospace Industries). It is published on green paper for the needs of AECMA-Members. it has been technically approved by the experts of the concerned Technical Committee fallo wing comment by the Member countries. Subsequent to the publication of this Prestandard, the technical
5、 content shall not be changed to an extent that interchangeability is affected, physically or functionally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Centre (NPS) and formal agreement of the Official Services of the Member countries it
6、will be submitted as a draft European Standard to CEN (European Committee for Standardization) for formal vote. 1998-1 1-30 AECMA Gulledelle 94 B-1200 BRUXELLES Mr Wright I I aecma 1998 COPYRIGHT Association Europeene Des Constructeurs de Materiel AerospaceLicensed by Information Handling ServicesST
7、D*AECMA PREN IbLS-ENGL 3778 LOL23LL 0035578 7T7 D Page 3 prEN 3615: 1998 I Scope This standard specifies the methods for determining the influence of exposure to a humid atmosphere on the following characteristics of fibre reinforced plastics: a) percentage of absorbed moisture; b) visual aspect. Th
8、is standard applies to all laminates, whatever the nature of the reinforcement and organic matrix used, unless otherwise indicated in the material standard andlor technical specification. 2 Norma tive referen ces This European Standard incorporates by dated or undated reference provisions from other
9、 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 Standard only when incorporated in it by amendment or r
10、evision. For undated references the latest edition of the publication referred to applies. EN 2331 Aerospace series - Test methods for the determination of the resin content of woven textile glass fibre fabric preimpregnate EN 2564 Aerospace series - Carbon fibre laminates - Test method for the dete
11、rmination of the fibre and resin fractions and porosity content 1) EN 2823 Aerospace series - Fibre reinforced plastics - Test method for the determination of the effect of exposure to humid atmosphere on physical and mechanical characteristics 1) 3 Definitions For the purposes of this standard, the
12、 following definitions apply. 3.1 Absorption specimens Specimens designed to measure the percentage of absorbed humidity and to evaluate changes in the visual aspect after exposure. 3.2 Equilibrium condition (EN 2823) Condition of the material exposed to a specified hygrometry when it has reached co
13、nstant mass. 3.3 Constant mass (EN 2823) Mass 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 AECMA Prestandard at the date of publication of this standard COPYRIGHT Ass
14、ociation Europeene Des Constructeurs de Materiel AerospaceLicensed by Information Handling ServicesSTDeAECMA PREN 3b15-ENGL 1778 = 1012311 0015577 835 D Page 4 prEN 3615: 1998 4 Methodology Determination of the percentage of absorbed humidity and of changes in appearance in accordance with the follo
15、wing sequence: a) in conformity with Ficks law (reaching the condition of equilibrium), according to EN 2823. Determine the highest possible temperature of exposure which guarantees that the material behaves b) Determine the initial mass. Two methods are applicable. Method A (as-molded material) sha
16、ll preferably be used. Wherever there is doubt as to relative humidity or the non-respect of conditions in 7.3.1 .I, method B (drying) shall be used. c) reach the condition of equilibrium. Expose the absorption specimens to the specified humidity and temperature conditions until they NOTE: These con
17、ditions either reproduce the effects of temperature and relative humidity on in-service parts or provide standard conditioning to enable a comparison of the behaviour of materials. 5 Apparatus 5.1 humidity to within f 3 %. Climatic chamber capable of maintaining the specified temperature to within I
18、l OC and relative 5.2 Desiccator 5.3 Balance accurate to within 0,l mg 5.4 Magnifying glass with magnification of approximately 10 X 5.5 Air circulating oven capable of maintaining the required temperature to within f 5 OC. 5.6 Clean and dry absorbent cloth or filter paper 5.7 Sealed container: meta
19、llized polythene bag or airtight metal or glass enclosure. 6 Specimens All the aspects in the manufacturing process (particularly surface finish) influence the test results. At least one absorption specimen shall be kept as a reference to evaluate changes in appearance. The number of plies of absorp
20、tion specimens shall be calculated so that the panel is symmetrically arranged in layers, a fibre percentage in conformity with the material standard and a thickness in conformity with the requirements in table 1: - unidirectional preimpregnates: unidirectional (Oo) or crossed (Oo/900) lay-up; - fab
21、rics: all plies warpwise in the same direction. The number and nature of peel plies or of the mould release agent used shall be defined. COPYRIGHT Association Europeene Des Constructeurs de Materiel AerospaceLicensed by Information Handling ServicesPage 5 prEN 361 5: 1998 e For each type of lay-up,
22、one or two sets (see 7.2.1) of specimens shall be made in accordance with figure 1 and table 1. (75 k 1) r b a b - (75 f 1) (2 k 0,2) a - Figure 1 Table I Dimensions in millimetres The faces of the panels shall be as demoulded after removing any eventual peel plies. The machining of the edges is to
23、be carried out avoiding overheating and delamination. 7 Procedure 7.1 Exposure conditions 7.1.1 Relative humidity This shall be specified. Standard condition: (85 I:) % Optional: (95 :;)Yo 7.1.2 Determination of exposure temperature For each family of fibres/resin/temperature, apply the same procedu
24、re to the absorption specimens as the one provided for traveller specimens in EN 2823. COPYRIGHT Association Europeene Des Constructeurs de Materiel AerospaceLicensed by Information Handling ServicesSTD-AECMA PREN 3bLS-ENGL 1998 m LO123Ll 0015581 Y93 W Page 6 prEN 3615: 1998 7.2 Determination of the
25、 percentage of absorbed humidity 7.2.1 Determination of initial mass 7.2.1 .I Method A Cut out a set of absorption specimens and weigh them within 30 min following demoulding. If this is not possible, the specimens shall be placed in the sealed container at ambient temperature for a period not excee
26、ding 72 h. Mo is the weight of each specimen. 7.2.1.2 Method B Cut out two sets of specimens. Weigh each specimen in the first set (M,) The second set shall be kept as a reference to determine the initial mass. Each specimen in the second set shall be: - weighing before drying (m,); - dried accordin
27、g to 7.2.2; - weighing after drying (m2). 7.2.2 Dry the specimens in an oven according to the sequence: Determination of constant mass after drying a) 72+20 h at (50 f 5) “C ( 0) b) 72+20 h at (70$r5)“C ( 0) c) x h at (90 k 5) “C Prior to each weighing, leave the specimens to cool to room temperatur
28、e in a desiccator. Any moisture pick- up shall be avoided during this operation. Weigh immediately on removal from the desiccator. The drying period x corresponds to the time required for the specimens to reach a constant mass. Constant mass being defined as three successive weighings of the travell
29、er specimens carried out at 72 h intervals (see figure 2) and which complies with the formula below: where: P, represents the mean weights of the travellers specimens at the time ti. COPYRIGHT Association Europeene Des Constructeurs de Materiel AerospaceLicensed by Information Handling ServicesSTD-A
30、ECflA PREN 3b15-ENGL 1778 1012311 0015582 327 = Page 7 prEN 3615: 1998 1-72-1 72 I t (h) Figure 2 If the criterion above is not satisfied, resume drying at c) as many times as necessary. 7.2.3 Exposure to humid atmosphere Place the absorption specimens in the climatic chamber at the specified relati
31、ve humidity (see 7.1 .I) and at the exposure temperature determined according to EN 2823. The contact between: - the specimens themselves; - the specimens and the walls of the chamber and (or) specimen supports; shall be point contact in order to ensure maximum exposure. 7.2.4 Frequency of weighing
32、At the beginning of exposure, it is recommended that weighings be made each day. This interval between weighings may be prolonged to one week depending on developments in the moisture pick-up curve. 7.2.5 Remove the specimens from the climatic chamber and wipe them to remove condensation with the cl
33、oth or paper. Allow them to cool to room temperature in a sealed container to reduce moisture loss to a minimum. Weigh immediately to the nearest 0,l mg (MJ. Immediately place the specimens in the climatic chamber again if further exposure is to take place. Removal of specimens and weighings 7.2.6 I
34、f specified, exposure shall be continued until constant mass is reached. For specimens of a thickness of (2 k 0,2) mm constant mass is reached when the difference between three successive weighings carried out at 168 h intervals (see figure 3) on the absorption specimens and in conformity with the f
35、ormula below: Determination of the equilibrium condition where: Mj represents the mean weights of the travellers specimens at the time II. COPYRIGHT Association Europeene Des Constructeurs de Materiel AerospaceLicensed by Information Handling ServicesFigure 3 If the temperature is lower than 70 OC,
36、the time interval between each weighing to define constant mass shall be determined by trials, the value of the difference remaining as above. 7.3 Examination after exposure Examine each specimen after exposure, with the magnifying glass if required, compare it with a reference specimen. 8 Expressio
37、n of resu Its The percentage of absorbed moisture is calculated according to 8.2. The results are to be represented on a percentage of absorbed humidity time or square root of time diagram. 8.1 Method A: Mo is the result of the weighing of each specimen. Method B: Mo is calculated according to the f
38、ormula: Mass of specimen in original condition (Mo) where: M, y rn, m2 is the mass of each absorption specimen before exposure, in grammes; is the percentage of absorbed moisture of each specimen before exposure; is the mass of each reference specimen before drying, in grammes: is the mass of each r
39、eference specimen after drying, in grammes. Calculate i, mean moisture percentage of the reference specimens before exposure. COPYRIGHT Association Europeene Des Constructeurs de Materiel AerospaceLicensed by Information Handling ServicesSTD-AECMA PREN 3bLS-ENGL 1998 = LOL23LL U015584 LTZ Page 9 prE
40、N 3615: 1998 8.2 Percentage of absorbed moisture after exposure where: HL Mo M2 is the percentage of absorbed moisture of each specimen after exposure; is the initial mass of each specimen, in grammes; is the mass of each specimen after exposure, in grammes. 8.3 Percentage of absorbed moisture after
41、 exposure, based on the resin 2) 1 O0 (I00 - M,) HN=HLx where: HN HL Mf is the percentage of absorbed moisture of each specimen based on resin weight; is the percentage of absorbed moisture of each specimen after exposure; is the fibre content by mass as a percentage measured according to EN 2331 fo
42、r glass fibres or EN 2564 for carbon fibres. 8.4 Percentage of absorbed moisture after exposure based on 60 % fibre by volume 2) 40 H6, = HL x (I00 - Vf) where: HL Vf is the percentage of absorbed moisture of each specimen after exposure; is the percentage of absorbed moisture of each specimen corre
43、cted to 60 % fibre by volume; is the fibre content by volume as a percentage measured according to EN 2564 for carbon fibres and according to EN 2331 for glass fibres. 8.5 Note the observed changes in the following characteristics: Evaluation of changes in appearance - colour (type and uniformity);
44、- opacity for translucent laminates; - gloss of the surface. Also record if the following defects are present: - splits and cracks; - blisters, pitting or other similar defects; - degraded materials removed easily by rubbing; - tackiness; - delamination, warping or other distortion. 2) Not applicabl
45、e to aramides COPYRIGHT Association Europeene Des Constructeurs de Materiel AerospaceLicensed by Information Handling Services STD-AECMA PREN 3b15-ENGL 1998 = 1012331 0035585 O39 Page 10 prEN 3615: 1998 9 Designation EXAMPLE: EN361 5685 - Number of this standard ?-I Method before exposure (see 7.2.1
46、) I Humidity level (see 7.1.1) 10 Test report It shall contain the following information: - designation (see 9); - complete information ensuring traceability of the material (trade mark, acceptance date, batch number, etc.); - the type of specimen (manufacturing method, dimensions, surface finish, p
47、eel ply, mould release agent; - the fibre content measured according to EN 2331 (glass) or EN 2564 (carbon); - the drying period x prior to exposure (method B); - the temperature and length of exposure; - the percentage of moisture absorbed by each specimen and the corresponding pick-up curve; - changes in appearance; - any incident likely to have affected the results. COPYRIGHT Association Europeene Des Constructeurs de Materiel AerospaceLicensed by Information Handling Services
