1、BRITISH STANDARD AEROSPACE SERIES BS EN 2155-8:1989 Test methods for transparent materials for aircraft glazing Part 8: Determination of optical distortion This European Standard EN 2155-8 has the status of a British Standard UDC 629.73.023.26:620.1:535.5BSEN2155-8:1989 This British Standard, having
2、 been prepared under the directionof the Aerospace Standards Policy Committee, waspublished under the authorityof the Board of BSI on 30November 1989 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference ACE/62 Draft for comment 88/70404 DC ISBN 0 580 1793
3、1 1 Cooperating organizations The European Committee for Standardization, under whose supervision this European Standard was prepared, comprises the national standards organizations of the following Western European countries. Austria Oesterreichisches Normungsinstitut Belgium Institut belge de norm
4、alisation Denmark Dansk Standardiseringsraad Finland Suomen Standardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Icelandic Council for Standardization Ireland National Standards Aut
5、hority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxemburg Inspection des travails et des mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Instituto Espaol de Normalizacin Sweden Standardiseringsko
6、mmissionen i Sverige Switzerland Association suisse de normalisation United Kingdom British Standards Institution Amendments issued since publication Amd. No. Date of issue CommentsBSEN2155-8:1989 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii Brief his
7、tory 2 Text of EN 2155-8 3 National appendix A Inside back cover National appendix B Inside back coverBSEN2155-8:1989 ii BSI 12-1999 National foreword This British Standard has been prepared under the direction of the Aerospace Standards Policy Committee and is the English language version of EN2155
8、 “Aerospace series. Test methods for transparent materials for aircraft glazing” Part 8 “Determination of optical distortion” published by the European Committee for Standardization (CEN). EN 2155-8 was produced as a result of international discussion in which the UK took an active part. A British S
9、tandard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cov
10、er, an inside front cover, pagesi andii, theENtitle page, pages2 to4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME E
11、UROPENNE EUROPISCHE NORM EN 2155-8 March1989 UDC629.73.023.26:620.1:535.5 Key words: Aircraft industry, glazing, transparent plastics, glass, tests, optical properties, distortion English version Aerospace series Test methods for transparent materials for aircraft glazing Part 8: Determination of op
12、tical distortion Srie arospatiale Mthodes dessais pour matriaux transparents pour vitrages aronautiques Partie 8: Dtermination de la distorsion optique Luft- und Raumfahrt Prfverfahren fr transparente Werkstoffe zur Verglasung von Luftfahrzeugen Teil 8: Bestimmung der optischen Verzerrung This Europ
13、ean Standard was accepted by CEN on 1988-03-17. CEN members are bound to comply with the requirements of CEN Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
14、 concerning such national standards may be obtained on application to the CEN Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member int
15、o its own language and notified to CEN Central Secretariat has the same status as the official versions. CEN members are the national standards organizations of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxemburg, Netherlands, Norway, Portugal, Spain, Swed
16、en, Switzerland and UnitedKingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels CEN 1989 Copyright reserved to all CEN members Ref. No. EN 2155-8:1989 EEN2155-8:1989 BSI 12-1999 2 Bri
17、ef history This European Standard has been prepared by the European Association of Aerospace Manufacturers (AECMA). After enquiries and votes carried out in accordance with the rules of this Association, this Standard has successively received the approval of the National Associations and the Offici
18、al Services of the member countries of AECMA, prior to its presentation to CEN. According to the Common CEN/CENELEC Rules, following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxemburg, Netherlands,
19、Norway, Portugal, Spain, Sweden, Switzerland and the UnitedKingdom. Contents Page Brief history 2 1 Scope and field of application 3 2 References 3 3 Definitions 3 4 Apparatus 3 5 Specimens 3 6 Procedure 3 7 Expression of results 3 8 Test report 3 Figure 1 3EN2155-8:1989 BSI 12-1999 3 1 Scope and fi
20、eld of application This standard specifies the method of measurement of optical distortion of sheets in transparent materials, which consists of determining the change of deviation over the entire area of the sheet. The method allows sheets to be viewed at differing angles which are specified accord
21、ing to the quality of the sheet under test. 2 References EN 2155-6, Aerospace series Test methods for transparent materials for aircraft glazing Part 6: Determination of optical defects. 3 Definitions Optical distortion is defined as local variation of optical deviation which results in distortion o
22、f the image perceived on viewing through the panel. Thus known straight lines become crooked or curved. 4 Apparatus A grid board having line spacing of 25mm is mounted vertically. A graticule having a system of equally spaced lines in two directions at90 to each other is designed to be used with a s
23、uitable lantern projector so that at a distance of4,5m the projected image can be made coincident with the grid board. To avoid distortion of the image, measurement shall be restricted to a square about 1m 1m at the grid board. An iris diaphragm may be useful to reduce the aperture of the lens. The
24、specimen shall be mounted so that the area being examined is1,2m from the grid board. The mounting arrangement shall allow the specimen to be placed at varying inclination to the horizontal plane. 5 Specimens For the purpose of this standard, the specimens are entire sheets. The entire surface of ea
25、ch specimen shall be carefully cleaned avoiding scratching or crazing. 6 Procedure 6.1 Maximum gradient With the specimen mounted at the specified viewing angle, the maximum gradient of the projected image with respect to the grid board lines in both directions shall be assessed. The specimen shall
26、be rotated 90 in its own plane and the same assessment repeated. In cases of doubt the image of the defect shall be brought to the optical axis of the apparatus and projector adjustments made to overcome line shift due to displacement. 6.2 Sharp discontinuities Sharp discontinuities “d” in the proje
27、cted image shall be measured as indicated inFigure 1. NOTEThe examination for sharp discontinuities, typically shown inFigure 1 is necessary in addition to the examination for major and minor defects in EN2155-6 since inhomogenities resulting in change of refractive index may not show up in EN2155-6
28、. 7 Expression of results The gradient in each area of distortion shall be expressed as a slope e.g. 1 in 17; sharp discontinuities shall be expressed as measured as displacement in mm. 8 Test report At each of the specified viewing angles as specified in the material standard, the number of occasio
29、ns when the gradient is steeper than the agreed limits shall be reported; likewise the number of occasions when the discontinuity “d” exceeds the specified limit shall be reported. Figure 1 4 blankBSEN2155-8:1989 BSI 12-1999 National appendix A The United Kingdom participation in the preparation of
30、this European Standard was entrusted by the Aerospace Standards Policy Committee (ACE/-) to Technical Committee ACE/62 upon which the following bodies were represented: British Plastics Federation Ministry of Defence Society of British Aerospace Companies Limited National appendix B The British Stan
31、dard corresponding to the European Standard referred to in the text is identical in number and title with that given in clause2.BS EN 2155-8:1989 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. I
32、t presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or editions. It is the constant aim o
33、f BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this BritishStandard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel:020899690
34、00. Fax:02089967400. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Te
35、l:02089969001. Fax:02089967001. In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as BritishStandards, unless otherwise requested. Information on standards BSI provides a wide range of information on national, Europ
36、ean and international standards through its Library and its Technical Help to Exporters Service. Various BSI electronic information services are also available which give details on all its products and services. Contact the Information Centre. Tel:02089967111. Fax:02089967048. Subscribing members o
37、f BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. For details of these and other benefits contact Membership Administration. Tel:02089967002. Fax:02089967001. Copyright Copyright subsists in all BSI publications. BSI also hold
38、s the copyright, in the UK, of the publications of the international standardization bodies. Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, photocopying, recording
39、 or otherwise without prior written permission from BSI. This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel:02089967070.
