BRITISH STANDARD AEROSPACE SERIES BS EN 2155 19 1997 Test methods for Transparent materials for aircraft glazing — Part 19 Determination of craze resistance The European Standard EN 2155 19 1996 has t[.]
BRITISH STANDARD AEROSPACE SERIES Test methods for Transparent materials for aircraft glazing — Part 19: Determination of craze resistance The European Standard EN 2155-19:1996 has the status of a British Standard ICS 49.025.99 BS EN 2155-19:1997 BS EN 2155-19:1997 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee ACE/62, Aerospace structural transparencies and non-reinforced plastics, upon which the following bodies were represented: British Plastics Federation Defence Research Agency Society of British Aerospace Companies Limited This British Standard, having been prepared under the direction of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 February 1997 © BSI 12-1998 The following BSI references relate to the work on this standard: Committee reference ACE/62 Draft for comment 94/715195 DC ISBN 580 26377 Amendments issued since publication Amd No Date Comments BS EN 2155-19:1997 Contents Committees responsible National foreword Foreword Text of EN 2155-19 © BSI 12-1998 Page Inside front cover ii i BS EN 2155-19:1997 National foreword This British Standard has been prepared by Technical Committee ACE/62 and is the English language version of EN 2155-19: 1996 Aerospace series — Test methods for transparent materials for aircraft glazing — Part 19: Determination of craze resistance published by the European Committee for Standardization (CEN) EN 2155-19 was produced as a result of international discussion in which the United Kingdom took an active part A British Standard 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 cover, an inside front cover, pages i and ii, the EN title page, pages to 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 ii © BSI 12-1998 EN 2155-19 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM August 1996 ICS 49.040.10 Descriptors: Aircraft industry, glazing, translucent glasses, transparent plastic, test, determination, crack strength English version Aerospace series — Test methods for transparent materials for aircraft glazing — Part 19: Determination of craze resistance Série aérospatiale — Méthodes d’essais pour matériaux transparents pour vitrages aéronautiques — Partie 19: Détermination de la résistance au fendillement “crazing” Luft-und Raumfahrt — Prüfverfahren für transparente Werkstoffe zur Verglasung von Luftgahrzeugen — Teil 19: Bestimmung der Spannungsrißbeständigkeit This European Standard was approved by CEN on 1995-04-13 CEN members are bound to comply with the CEN/CENELEC 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 concerning such national standards may be obtained on application to the 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 into its own language and notified to the Central Secretariat has the same status as the official versions CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom CEN European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels © 1996 Copyright reserved to CEN members Ref No EN 2155-19:1996 E EN 2155-19:1996 Foreword This European Standard has been prepared by the European Association of Aerospace Manufacturers (AECMA) After inquiries and votes carried out in accordance with the rules of this Association, this Standard has received the approval of the National Associations and the Official Services of the member countries of AECMA, prior to its presentation to CEN This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February 1997, and conflicting national standards shall be withdrawn at the latest by February 1997 According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom Contents Foreword Scope Definition Apparatus and materials Specimens Conditioning Procedure Test report Figure — Loading condition for flat sheet Page 3 3 4 © BSI 12-1998 EN 2155-19:1996 Scope This standard specifies the test method to determine the resistance of transparent sheet to the effect of a solvent environment while subjected to a load No method has been developed yet for specimens with a thickness < mm; for such material, a test method shall be agreed between the manufacturer and the purchaser Definition For the purposes of this standard, the following definition applies: The craze resistance is defined as the absence of crazing (micro-cracks) when propanol-2 (isopropyl alcohol) is applied under controlled conditions for a period of 30 to the surface of a specimen experiencing a fibre stress as stated in the material standard Apparatus and materials 3.2 Suitable masses to be from the loading point to induce the required stress 3.3 Propanol-2 (isopropyl alcohol) of analytical quality 3.4 Filter paper Specimens 4.1 The specimens shall be cut from a sheet and shall have a high polish and be free from surface damage 4.2 Specimens shall be cut of dimensions 175 mm × (25 ± 1) mm × (6 ± 0,5) mm; the cut edges shall be machined smooth Material with a thickness > mm shall be machined on one face only to mm thickness and the non-machined face shall be tested 4.3 A hole of mm diameter shall be drilled with its centre 15 mm from one end and on the centre line of the specimen to facilitate loading (see Figure 1) 3.1 A cantilever loading arrangement as shown in Figure Figure — Loading condition for flat sheet © BSI 12-1998 EN 2155-19:1996 Conditioning 5.1 The specimens shall be conditioned at (23 ± 2) °C, (50 ± 5) % relative humidity for at least 48 h prior to testing under the same conditions 5.2 The apparatus and solvent (in a suitably stoppered container) shall be pre-conditioned as for the specimens 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) °C for a period of 30 After allowing to cool to room temperature under draught-free conditions the specimens are annealed in an air-circulating oven to the manufacturer’s 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 acrylic material the test specimens shall be freely suspended in an air-circulating oven and maintained at a temperature of (75 ± 2) °C for a period of 16 h and then allowed to cool under draught-free conditions Prior to testing the width and thickness shall be measured at the position of the fulcrum with an accuracy of ± 0,02 mm 6.3 The specimens shall be set up as cantilever beams and loaded with the specified outer fibre stress which is calculated from the following formula 6.4 After application of the load for 10 and while still under load, propanol-2 (isopropyl alcohol) shall be applied to each specimen by means of a 20 mm × 20 mm filter paper patch placed on the upper surface and centered on the fulcrum and kept wet with the solvent 6.5 The filter paper patch shall be removed after 30 and the specimen examined for evidence of crazing 6.6 There shall be no crazing (group of cracks) on the tested surface Individual cracks shall be disregarded Unless the cracks are over mm in length, edge crazing shall be disregarded Test report The test report shall include the following: — number of this standard; — material type; — batch number; — stress applied; — appearance of specimen after test; — compliance/non-compliance with the requirements of 6.6 load (newtons) = s B A 6L where: s B A L is the outer fibre stress, in megapascals; is the specimen width measured, in millimetres; is the specimen thickness measured, in millimetres; is the distance from the fulcrum point to the load application 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