1、iCEN PREN*2155-03 91 3404589 0013486 O - - -% - Approved by COMITG DE NORMALISATION of A.E.C.M.A. 1991-04-10 A. E. C. M. A. STAN DAR D prEN 2155 7 The equivalent versions in French and Gerinaii languages can be supplied Iiy B.N.A.E . Technopolis 54 . 199, rile Jean-Jacques Roiicseaii 92138 ISSY LES
2、MOULINEAUX CEDEX - FRANGE NORME A.E.C.M.A. A.E.C.M.A. NORM Part 3 Edition 1 April 1991 EDIT PAR LASSOCIATION EUROPENNE DES CONSTRUCTEURS DE MATERIEL AEROSPATIAL 88. boulevard Maleslierbec, 75008 PARIS -TL. 45-63-82-85 UDC : Key words ENGLISH VERSION Aerospace series Test methods for transparent mate
3、rials for aircraft glazing Part 3 - Determination of refractive index . Srie arospatiale Mthodes dessais pour ma t r i a ii x trans pa re nt s pour vitrages aronautiques Partie 3 - Dtermination de lindice de rfraction Luft- und Raumfahrt Prfverfahren fr transparente Werkstoffe zur Verglasung von Luf
4、tfahrzeugen Teil 3 - Bestimmung der B rec li u n g s i n dex This .Aerospace series, standardhas been drawn up under the responsibility of AECMA (Association Europenne des Constructeurs de Matriel Arospatial). It is published on yellow paper in three equivalent versions (English, French, German). It
5、 will be submitted as a draft European Standard to CEN (European Committee for Standardization) for final vote. O 0 0 I l O- - CEN PREN*2155-03 %-i 3404589 0033487 2 - 1 Scope arid field of appl.icotion liiis standiird describes tlie inetliod used ror the determination of the refractive index alipli
6、cable for transpareul: inatarialc used in nircrof t laziiig 2 Purpose of the method lhic method is used for the control of purity and coinposition of materials, llie refractive index shall be considered when decigriiiig the partn. 3 efiiiition llie refractive index n is the ratio of the velocity of
7、light iii i1 uacuuin to that in tlie material masured at 23C for the sodium E) line wavelength 5C9,3 nanometrec. 23 D 4 Apparatus and paterial 4.1 Abbe refractometer-or any other refractometer that can be shown to give the same results, the accuriicy shall te 0,001. 4.2 Source of white .light. 4.3 C
8、ontacting liquid Saturated aqueous solution of zinc ciiloride made slightly acid. 5 Specimen The test specimen cut from tlie sninple shall be o such a size as will fit on the face of tire fixed half of the refractometer prisms, Por the Abbe refractometer the dimensiFnc are as Follows : - 6 mm wide -
9、 12 mm long - 3 aiin tliick. - Previous page is blank I CEN PREN*2155-03 91 m 3404589 0013488 4 m prEN 2155-3 Page 4 For necessary accuracy tlie surface of the tcst cpecitni!ri in coiitact with the prisin shall he sufficieiitly flat and pc)lisliad iii ortler to obta Lii. satisfactory contact between
10、 tliu test speciiiieii aiid the prism. This contact is indicated by ttie clividiiig line between tlie light and dark Iialver; of tlie eyepiece field appcariiig sliarp and striight. A second surface is prepared iiiidtir the cmc coiitlitioris pcrpendiculnr to the first aiid o11 one end of tlie t ct cp
11、eclincii. These tim surfaces shall intersect along a sliarp line wtttiout i1 bevelled ur rounded edge. 6 Conditionirig rile speciiiieii sliall be prcconditioiicd at (23 4 2)OC, (50 5 51% relative tiiiniidity for at least 48 h prior to tecling, Before the deteriiiiiiotion, tlie ;1 p pa rii tu E; e;li
12、n 11 re iic II t li e s mie corid 1 L: ions . Tlic test 1s to be pcrforiiied immediately after cuiitlitioning. f Procedure llie procedure for tlia Abbe refrnctonieter is described. For other refractometers tlia procedure may be niodif ied if necessary, Thc determination is carried out at (23 -1- 0,S
13、)OC. A small drop of the contacting liquid is placed on the polisliFd surface of the test specimen which is then placed in firm contact with the surface of tlie prism with the polished mall edge of the specimen towards the source of light. The index arm of the refractometer is then adjusted until ha
14、lf of the eyepiece field is dark. The conipensator (Ainici prisms) drum io then adjusted until all colour is removed from the field, after which the index arm is adjusted by nienns of the vernier until the dividing line between the liglit and dark portions of the field coincides e:tactly with tlir p
15、oint of intersection o the eyepiece cross hairs. The refractive index for ttie sodium D liiie is then read on the instrument scale. 8 Test report The test repart shall iriclude the. fol.lowing : - reference to this standard, - refractive index to tlie iiearest significaiit f igiire warranted b;, the precision and repeatability of tneasuremeitt (i tlie refractive index is expressed to more than three significant figures, the wavelength of light for which the measurunieiit was made is also reported), - position on tlie original sample from wliicli th test speciiiien was cut.
