1、prEN2342 A. E.C.M.A. STANDARD NORME A.E.C.M.A. A.E.C.M.A. NORM Edition 1 January 1982 ENGLISH VERSION HEAT AND CRAZING RESISTANT ACRYLIC SHEETS FOR AIRCRAFT GLAZING TECHNICAL SPECIFICATION AEROSPACE SERIES FEUILLES DACRYLIQUE RESISTANT LUFT- UND RAUMFAHRT A LA CHALEUR ET AU CRA2ING SPECIFICATION TEC
2、HNIQUE WRMEFORM- UND SPANNUNGSRISSBESTNDIGE ZUR VERGLASUNG VON LUFTFAHRZEUGEN POUR VITRAGES AERONAUTIQUES ACRY LGLASPLATTEN SCRIE AEROSPATIALE TECHNISCHE SPEZI FIKATION This industrial standard for the aerospace sector has been drawn up under the responsibility of AECMA (Association Europenne des Co
3、nstructem de Matriel Arospatial). It is published on yell0 w paper in three equivalent versions (English, French, German). It will be submitted to CEN (European Committee for Standardization) as a draft European Standard. I The equivalent venions in French and German languages COMITE DE NORMALISATIO
4、N can be supplied by B.N.A.E., 8, rue Moreau-Vauthier 92100 BOULOGNE-BILLANCOURT - FRANGE. I Approved by of A.E.C.M. A. 19881.01 -26 I l prEN2342 Page 2 AECMA PREN23Li2 82 m 2012312 0002984 1 m - =- QI, c ON TENTS 1 2 3 4 5 6 7 a 9 10 11 12 13 14 15 16 17 18 19 20 SCOPE AND FIELD OF APPLICATION REFE
5、RENCES MATERIAL CLASSIFICATION PHYSICAL PROPERTIES OPTICAL DEFECTS OPTICAL PROPERTIES RESISTANCE TO WEATIHERING THERMAL PROPERTIES MECHANICAL PROPERTIES SUSCEPTIBILITY TO SOLVENT CRAZING DIMENSIONS QUALIFICATION APPROVAL FORMULATION CHANGES SAMPLING AND INSPECTION ACCEPTANCE TESTS PROTECTION AND PAC
6、KAGING STORAGE CONDITIONS MARKING COMMENTS ON THE TABLE AECMA PREN23q2 82 m LO12311 O002985 3 m prEN2342 Page 3 A.E.C.M.A. STANDARD prEN2342 HEAT AND CRAZING RESISTANT ACRYLIC SHEETS FOR AIRCRAFT GLAZING TECHNICAL SPECIFICATION 4 SCOPE AND FIELD OF APPLICATION This standard specifies the supply of h
7、eat and crazing resistant cast transparent acrylic sheets for aircraft glazing. REFERENCES EN2155, EN2.55-1 to EN2155-22, Test methods for transparent -. materials for aircraft glazing 1) . MATERIAL The sheets shall be made from a modified acrylic polymer or Co-polymer mainly consisting of methyl me
8、thacrylate and shall be controlled under the conditions specified herein. CLASSIFICATION The material shall be available in four classifications as follow : Classe Oa CLasse Ob Classe Oc Classe d with optical deviation not greater than 130“ (0,00043 rad). Optical distortion not greater than that spe
9、cified in clause 7.5 when the sheet is mounted at an optical incidence of 60“. with optical deviation not greater than 3 (0,00087 rad). Optical distortion not greater than that specified in clause 7.5 when the sheet is mounted at an optical incidence of 60. _-_- with optical deviation not greater th
10、an 6 (0,00175 rad). Optical distortion not greater than that specified in clause 4.5 when the sheet is mounted at an optical incidence of 45O. with optical deviation not greater than 10 (O;0O291 rad). Optical distortion not greater than that; specified in cl.ause 7.9 when.the sheet is mounted at zer
11、o optical incidence. . 1) in preparatjon AECMA PREN2342 82 = LOL23LL 0002986 5 9 ,_ . _. prEN2342 Page 4 5 PHYSICAL PROPERTIES 5.1 Density Mass density of the material as determined in EN2155-1 shall be as stated in Gh.e table. 5.2 Water absorption The water absorption as determined in EN2155-2 l) s
12、hall not be greater than the value stated in the table. 6 OPTICAL DEFECTS 6.1 The sheets viewed through the cast surfaces shall be colourless. 6.2 The sheets shall have a high polish and be free from scratches and grazes. 6.3 Sheets in classification Oa or Ob shall be examined for defects as in EN21
13、55-6 and shall satisfy the following clauses : 6.3;l There shall be no crazing or voids 6.3.2 Sheets shall not contain defects larger than those defined in EN2155-6 6.3.3 Sheets containing major and/or minor defects as defined in EN2155-6 shall be acceptable providing : 1) An area enclosed by a circ
14、le of radius 150 mm with each major defect as centre contains no other major defect and not more than three minor defects, 2) An area enclosed by a circle of radius 150 mm and centre at any point on the sheet which does not contain a major defect, contains not more than five minor defects. 6.4 Sheet
15、s in classification Oc or Od shall be examined for defects as in EN2155-6 to a standard agreed between manufacturer and purchaser. 7 OPTICAL PROPERTIES 7.1 Refractive index The refractive index as determined in .EN2155-3 l). shall be as stated in the table.- -, 1) in preparation b I) I *- -AECMA PRE
16、N2342 82 Ri LOL23LL 0002987 7 =- prEN2342 Page 5 7.2 Ultra-violet light transmittance The ultra-violet transmittance at any wavelength in the range 290 to 330 nm as determined in EN2155-4 shall not exceed the values shown in figure 1, 7.3 Visible light transmission The visible light transmission as
17、determined in EN2155-5 1 shall not be less than the values stated in the table. 7.4 Optical deviation The optical deviation as examined in ENZ155-7 shall not be greater than the value quoted in clause 4. 7.5 Optical distortion The optical distortion as determined in EN2155-8 and examined under the v
18、iewing angle specified in clause 4 shall not, present : - A gradient exceeding 1 in 17 for classes Oa and Ob and 1 in 12 for the other classes, - Discontinuities d exceeding 0,5 mm, 7.6 Haze As determined in EN2155-9 the average value shall not exceed that stated inthe tableand the maximum single va
19、lue obtained shall not exceed the stated value by more than 1%. 8 RESISTANCE TO WEATHERING 8.1 Resistance to accelerated weathering Resistance to accelerated weathering will be determined by EN2155-10 ; requirements may be inserted at a later date. 8.2 Resistance to natural weathering The periods an
20、d conditions under which the material is to be exposed shall be decided by agreement between the manufacturer and purchaser and in accordance with EN2155-11 l. If changes Fire recordeci the acceptabi3ity of the material shall be discussed between manufacturer and purchaser. - I 1) in preparation l A
21、ECMA PREN2342 82 LOL23LL 0002988 3 W prEN2342 Page 6 9 THERMAL PROPERTIES 9.1 Coefficient of linear thermal expansion The coefficient of linear thermal expansion as determined in EN2155-12 shall not exceed the figure stated in the table. 9.2 Deformation temperature under load The deformation tempera
22、ture as determined in EN2155-13 shall not be below that quoted in the tabbe. 9.3 1/10 Vicat softening temperature The softening point of the sheet as determined in EN2155-14 l) shall not be below the figure quoted in the table. L 1) in preparation 9.4 Thermal stability When tested as described in EN
23、2155-15, the test shwt shall meet the requirements of clauses 6.3 and 6.4 in this standard. It shall show negligible deterioration in its ultraviolet and visible light transmission. 9.5 Flammabili-ty Flammability will be determined by EN2155-16 ; requirement may be inserted at a later date. 10 MECHA
24、NICAL PROPERTIES 10.1 Tensile strength and elongation at break When tested as described in EN2155-17 l) no individual value for these properties shall be less than those stated in the table . 10.2 Impact strength When tested as described in EN2155-18 ) the impact strength of test specimens shall not
25、 be less than the value stated in the table. 11 SUSCEPTIBILITY TO SOLVENT CRAZING 11.1 Craze resistance When the specimens to be tested are subjected to the conditions of EN2155-19 at a stress of 14 MPa they shall show no signs of crazing. I. 12 13 14 15 prEN2342 Page 7 11.2 Retention of strength af
26、ter crazing Specimens subjected to the conditions of EN2155-20 shall be acceptable under a stress of 10,4 MPa. Failure of more than one specimen shall entail rejection of the batch. If one specimen fails, a further sample of 10 specimens from a different sheet shall be selected from the same batch a
27、nd tested under the same conditions. No specimen shall fail on re-test. DIMENSIONS 12.1 The sheet size and thickness shall be as specified in the contxact or order. 12.2 The thickness of a sheet at; any point. shall riot differ from the nominal thickness by more than & the value given in figure 2 fo
28、r the particular size range. QIJAALIFICATION APPROVAL Before any particular manufacturers materials are supplied as complying with this standard the manufacturer shall obtain qualification approval. Application for approval shall be submitted to the appropriate inspecting authority together with : 1
29、3.1 Evidence that the materials comply with all the reqiiirernents specified herein, 13.2 Sufficient material for which approval is sought to meet the test requirements of this standard, 13.3 Details of composition supplied in confidence to the inspecting authority if national. practice requires, 13
30、.4 Recommended forming and fabrication instructions, 13.5 Details of sheet thicknesses and maximum sizes available. FORMULATION CHANGES Any proposed change by the manufacturer in the formulation and/or the production process shall be notified to the approving authority. If significant the material s
31、hall be designated a new material requiring specific and separate approval. If approved the changed material shall be given a new name or trade symbol. SAMPLING AND INSPECTION 15.1 For a periodic test or batch test a single sheet of material shall be taken at random. The sheet shall be divtded into
32、two equal parts, one part shall be tested for compliance with clause 16 of this standard and the other retained for retest in the case of dispute within 3 months. 1) in preparation AECMA PREN2342 82 LOL23LL 0002790 7 prEN2342 Page 8 The term “batch“ refers to any number of sheets of the same casting
33、 mix. The term “periodic“ implies that the material shall be tested every three months or at periods agreed between manufacturer and inspection authority. The storage conditions of specimen shall be those recommended by the manufacturer. 15.2 At hhe discretion of the inspector anybatch of material-m
34、ay be . tested to the full requirements of this standard, 16 ACCEPTANCE TESTS Any manufacturers material granted qualification approval under this standard shall be subject to the following acceptance tests : 16.1 Each sheet - Optical defects according to clause 6.3 for classes Oa and Ob and accordi
35、ng to clause 6.4 for classes Oc and d - Optical deviation according to clause 7.4 - Dimensions according to clause 12. 16.2 Each batch - Deformation temperature under load according to clause 9.2 for - 1/10 Vicat softening temperature according to clause 9.3 for - Craze resistance according to claus
36、e 11.1. material 6 mm and more in thickness material less than 6 mm in thickness 16.3 Periodic - Ultra-violet light transmission according to clause 7.2 - Visible light transmission according to clause 7.3 - Haze according to clause 7.6 - Thermal stability according to clause 9.4 - Tensile strength
37、and elongation at break according to clause 10.1 - Retention of strength after crazing according to clause 11.2. 17 PROTECTION AND PACKAGING I 17.1 Individual sheets shall be protected on both surfaces by a paper or opaque plastic film adhered with a compatible adhesive which can readily be removed
38、without injury to the surfaces. The film shall adequately-protect the surfaces from damage during delivery, storage, handling and cutting operations. 17.2 Unless otherwise specified by the purchaser all sheets shall be segregated by thickness and size packed for domestic delivery, The container shal
39、l be suitable for maintaining the material in its original. condition and the sheets shall be supported to avoid damage, - - I i _ - i AECMA PREN2342 82 10123L3 0002993 9 psEN2342 Page 9 18 STORAGE CONDITIONS Sheets shall be stored, protected on both surfaces as defined in clause 17 and stacked in v
40、ertical racks with padded separators. The storage area shall be protected from extremes of temperature and humidity 19 MARKING Each sheet of niaterial shall be clearly marked on the protective backing with : . 19.1 The standard number 19.2 The name or trade symbol of the manufacturer as designated i
41、n the asproval 19.3 The manufacturers batch number or reference 19,4 The sheet thickness. NOTE : The marking called for in clauses 19.1 and 19.2 shall be spaced at approximately 60 cm intervals over the backing material. 20 COMrIMENTS ON THE TABLE While a number of the properties included in the tab
42、le are specific to heat and craze resistant acrylics and are not subject to variation, others do vary. Iri these instances a base minimum value, below which material would not be acceptable to the purchaser, is required. Therefore the value quoted intheMleis such a minimum figure (not a minimum aver
43、age). No specimen as tested according to the standard shall fall below the quoted value. b AECMA PREN2342 82 10123LL 0002792 O prEN2342 Page 10 TABLE . - Properties of craze and heat resistant transparent acrylic sheets 1) in preparation - 4 b? - pr EN2342 Page 11. O cy E E AECMA PREN2342 82 LOL23LL
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