1、AECMA PRENZL55-L7 L W LOL23LL 0002307 7 W -. 1 / Approved by COMITE DE NORMALISATION of A.E.C.M.A. 27-09-79 A.E.C.M.A. STANDARD NORME A.E.C.M.A. A. E.C.M.A. NORM - The equivalent venions in French and German languages can be supplied by B.N.A.E., 8, rue Moreau-Vauthier 92100 BOULOGNE-BILLANCOURT - F
2、RANCE. - prEN2155-19 Edition 1 Novemlwr 1981 ENGLISH VERSION TEST METHODS FOR TRANSPARENT MATERIALS FOR AIRCRAFT GLAZING PART 19 DETERMINATION OF CRAZE RESISTANCE AEROSPACE SERIES METHODES DESSAIS LUFT- UND RAUMFAHRT POUR MATCRI AUX TRANSPARENTS PRFVERFAHREN POUR VITRAGES AERONAUTIQUES FR TRANSPAREN
3、TE WERKSTOFFE PARTIE 19 ZURVERGLASUNGVONLUFTFAHRZEUGEN DETERMINATION DE LA RESISTANCE TEIL 19 AU FENDILLEMENT GRAZING) BESTIMMUNG DER SERIE AEROSPATIALE SPANNUNGSR ISSBESTNDIG KE IT This industrial standard for the aerospace sector has been drawn up under the responsibility of AECMA (Association Eur
4、openne des Constructeurs 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 Standardizati0n)as a draft European Standard. prEN2155-19 Page 2 CONTENTS 1 SCOPE AND FIELD OF APPLICATION 2 D
5、EFINITIONS 3 APPARATUS AND MATERIALS 4 SPECIMENS 5 CONDITIONING 6 PROCEDURE 7 EXPRESSION OF RESULTS 8 TEST REPORT 4 AECMA PREN2L55-17 1 W LO12311 0002311 5 W prEN2155-19 Page 3 A.E.C.M.A. STANDARD prEN2155-19 TEST METHODS FOR TRANSPARENT MATERIALS FOR AIRCRAFT GLAZING PART 19 - DETERMINATION OF CRAZ
6、E RESISTANCE SCOPE AND FIELD OF APPLICATION This standard specifies the resistance of transparent sheet to the effect of a solvent environment while set up as a cantilever beam with a load applied at the free end. No method has been developed yet for specimens thinner than 6 mm; for such material, a
7、 test method shall be agreed between supplier and customer. DEFINITIONS For the purposes of this standard the craze resistance is defined as the appearance or otherwise of crazing (cracks) when a solvent (isopropyl alcohol) is applied under controlled conditions for a period of 30 min to the surface
8、 of a specimen experiencing a fibre stress as stated in the material standard, The test is to be carried out at 23 i 2OC. APPARATUS AND MATERIALS 3.1 A suitable cantilever loading arrangement shall be set up as in figure 1, the fixed support and fulcrum being horizontal and parallel with radiused co
9、ntact faces, 3.2 Suitable masses may be hung from the loading point to induce the required fibre stress, 3.3 A supply of isopropyl alcohol of analytical reagent grade is required. SPECIMENS 4.1 The specimens shall cut from a sheet and shall have a high polish and be free from scratches and grazes. 4
10、.2 Five specimens shall be cut of dimensions 175 mm x 25 f 1 rnm x 6 f 0,5 mm; the cut edges shall be machine smooth. Material thicker than 6 mm shall be machined on one face only to 6 m thickness and the non-machined face shall be tested. prEN2155-19 Page 4 4.3 A hole 6 mm diameter shall be drilled
11、 with centre 15 mm from one end and on the centre line of the strip to facilate loading (see figure 1). filter paper patch 7 view crazing from I this sector A * 50 f / L,lOO 15 II II unloaded condition Il II II I !I 1 fixed support + 4 8=25 k I I I I I I I I I I I I load FIGURE 1 : Loading condition
12、 for flat sheet - measurements in millimetres 5 CONDITIONING 5.1 The specimens shall be conditioned at 23 f 2OC, 50 & 5% relative humidity for at least 48 h prior to testkg under the same conditions. 5.2 The apparatus and solvent (in a suitably stoppered container) shall be pre-conditioned as for th
13、e specimens. 6 PROCEDURE 6.1 For unstretched material the test specimens shall be freely suspended in an air circulating oven and maintained at a temperature of 155 2 2OC for a period of 30 min. After allowing to cool to room temperature under draught free conditions the specimens are annealed in an
14、 air- circulating oven to the manufacturers instructions, then allowed to cool to room temperature under draught free conditions. After annealing and cooling the width and thickness shall be measured at the position of the fulcrum with an accuracy of ,+ 0,02 mm. 6.2 For stretched material the test s
15、pecimens shall be freely suspended in an air circulating oven and maintained at a temperature of 75 f 2OC for a period of 16 h and then allowed to cool under draught free conditions. Prior to testing the width and thickness will be measured at the posi- tion of the fulcrum with an accuracy of r. 0,0
16、2 mm. AECMA PREN2155-19 A1 m 1012311 00023I13 9 m prEN2i55-19 Page 5 6.3 The specimens shall be set up as cantilever beams and loaded with the specified outer fibre stress.which may be calculated from-the formula : cr B AL 6L Load (newtons) = where : cr = outer fibre stress in ma B = width measured
17、in mm A = thickness measured in mm L = distance from the fulcrum point to the load application poinfinmnt, to the nearest 0,l mm. 6.4 After application of the load for 10 min and while still under load, isopropyl alcohol shall be applied to each specimen by means of a 20 mm square filter paper patch
18、 placed with one edge adjacent to the fulcrum and kept wet with the solvent. 6.5 The patch shall be removed after 30 min and the specimen examined for evidence of crazing. 6.6 Unless the cracks are over 3 mm in length, edge crazing shall be disregarded. 7 EXPRESSION OF RESULTS The appearance of crazing after 30 min shall be noted. 8 TEST REPORT The test report shall include the appearance of crazing at the outer fibre stress level employed.
