1、BRITISH STANDARD AEROSPACE SERIES BS EN 2155-21:1989 Test methods for transparent materials for aircraft glazing Part 21: Determination of resistance to crack propagation (K factor) This European Standard EN 2155-2 has the status of a British Standard. UDC 629.73.023.26:620.191.33BSEN2155-21:1989 Th
2、is British Standard, having been prepared under the directionof the Aerospace Standards Policy Committee, waspublished under the authorityof the Board of BSI andcomes into effect on 31 October 1989 BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference ACE/
3、62 Draft for comment 88/70404 DC ISBN 0 580 17926 5 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
4、 Normungsinstitut Belgium Institut belge de normalisation 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 fo
5、r Standardization Ireland National Standards Authority 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
6、Espaol de Normalizacin Sweden Standardiseringskommissionen i Sverige Switzerland Association suisse de normalisation United Kingdom British Standards Institution Amendments issued since publication Amd. No. Date of issue CommentsBSEN2155-21:1989 BSI 01-2000 i Contents Page Cooperating organizations
7、Inside front cover National foreword ii Brief history 2 Text of EN 2155-21 3 National appendix A Inside back coverBSEN2155-21:1989 ii BSI 01-2000 National foreword This British Standard has been prepared under the direction of the Aerospace Standards Policy Committee and is the English language vers
8、ion of EN2155 “Aerospace series. Test methods for transparent materials for aircraft glazing” Part21 “Determination of resistance to crack propagation (K factor)” published by the European Committee for Standardization (CEN). EN2155-21 was produced as a result of international discussion in which th
9、e UK 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 page
10、s This document comprises a front cover, an inside front cover, pages i and ii, theEN title page, pages 2 to 6, 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 in
11、side front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 2155-21 March 1989 UDC: 629.73.023.26:620.191.33 Key words: Aircraft industry, glazing, transparent plastics, glass, tests, strength, crack propagation English version Aerospace series Test methods for transparent materials for ai
12、rcraft glazing Part21: Determination of resistance to crack propagation (K factor) Srie arospatiale Mthodes dessais pour matriaux transparents pour vitrages aronautiques Partie21: Dtermination de la rsistance la propagation des criques (Facteur K) Luft- und Raumfahrt Prfverfahren fr transparente Wer
13、kstoffe zurVerglasung von Luftfahrzeugen Teil21: Bestimmung des Rifortpflanzungswiderstandes (K-Faktor) This European 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
14、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 CEN Central Secretariat or to any CEN member. This European Standard exists in three official versions (English,
15、 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 CEN Central Secretariat has the same status as the official versions. CEN members are the national standards organizations of Austria, Belgium, Denmark
16、, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxemburg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-105
17、0 Brussels CEN 1989 Copyright reserved to all CEN members Ref. No. EN 2155-21:1989 EEN2155-21:1989 2 BSI 01-2000 Brief 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 o
18、f this Association, this Standard has successively received the approval of the National Associations and the Official 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 Stan
19、dard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxemburg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the UnitedKingdom. Contents Page Brief history 2 1 Scope and field of application 3 2 Definitions 3 3 Apparatus 3 4 Specimens 3 5 Condi
20、tioning 3 6 Procedure 3 7 Expression of results 3 8 Test report 4 Figure 1 Driving yoke and blade for initiatingcracks in toughness specimens 4 Figure 2 Toughness specimen 5 Figure 3 The fracture zones on a failedspecimen 5 Table 1 Values of Z 6EN2155-21:1989 BSI 01-2000 3 1 Scope and field of appli
21、cation This standard specifies how the resistance to crack propagation of rigid transparent sheet is to be determined. 2 Definitions Resistance to crack propagation is defined either by fracture toughness K at failure, or by strain energy release rateat failure. The values of failing load and length
22、 of crack at fast fracture shall be determined by tensile tests with a specified constant rate loading using a pre-cracked standard specimen. 3 Apparatus 3.1 A tensile testing machine shall be provided such that the specimen can be loaded at a constant rate which will cause fracture in3 to5min. 3.2
23、Suitable grips shall be provided on this machine of sufficient width to grip the specimen i.e.at least50mm in width. Self-tightening wedge grips have been found suitable but great care shall be taken to avoid damaging the specimen. 3.3 A driving yoke and blade for initiating cracks in the specimens
24、shall be provided to the dimensions as illustrated inFigure 1. 4 Specimens Test specimens shall conform toFigure 2. The specimens width shall be measured to the nearest0,2mm and their thickness at the centre shall be measured to the nearest0,02mm. Five specimens shall be cut from each sample. 5 Cond
25、itioning 5.1 For testing at (23 2) C, (50 5)% relative humidity the specimens shall be conditioned for at least48h at this condition prior to testing. 5.2 For testing at (18 1) C the specimens shall be conditioned at this temperature for at least30min prior to testing. 6 Procedure 6.1 The resistance
26、 to crack propagation (toughness) of the material shall be determined as follows: 6.2 Initiation of cracks Cracks shall be initiated on opposite sides of the centrally located hole in the specimen so as to be oriented in the width direction. The distance between the heads of the initial cracks shall
27、 be between12,5mm and25,0mm so that the crack length at the point of instability will be between1/4 and1/2 of the specimen width. In initiating the cracks, the following procedure is recommended. A fine slot, approximately0,8mm deep is made with a jewellers saw. The driving yoke and blade shown in t
28、heFigure 1 are employed in initiating the cracks. With the specimen held firmly in a vertical position with its length horizontal, the blade is inserted through the central hole and seated in the saw cut. The yoke straddles the specimen and engages the blade in the squared notches. A light hammer ta
29、pping on the yoke is used to initiate the crack. Cracks shall be initiated under conditions of conditioning according to clause5.1 for testing under these conditions. For low temperature testing, cracks are initiated prior to conditioning at low temperature according to clause5.2. 6.3 Gripping and l
30、oading The specimen shall be gripped to approximately25mm from the ends. Care shall be taken to ensure proper alignment of the specimen. The specimen shall be loaded at a constant rate that will cause failure in3 to5min; (2,8 0,5)kN/min will be suitable for most thicknesses. 6.4 Crack length The fai
31、ling load, crack length at onset of fast fracture and test temperature shall be recorded. The crack length at onset of fast fracture may be determined by closely following the progress of the crack front during slow fracture and examination of the fracture surface (Figure 3 refers). The average crac
32、k length shall be recorded to the nearest0,2mm. Figure 3 is a sketch of the cross section of the specimen after failure taken at the centreline of the hole. 7 Expression of results 7.1 Fracture toughness Fracture toughness K shall be computed from the equation: W A -EN2155-21:1989 4 BSI 01-2000 7.2
33、Strain energy release rate An alternative method of assessment is to use strain energy release ratecomputed from the equation: where: 8 Test report The test report shall include: 8.1 the fracture toughness expressed in MPa.mm 1/2at (23 2) C and at (18 1) C. 8.2 and/or the strain energy release rate
34、expressed in kJ/m 2at (23 2) C and at (18 1) C. P = failure load in N t = thickness of the specimen in mm B = specimen width in mm E = modulus of elasticity in MPa, determined in a tensile test under a stress of10MPa ; = 3,141 Z = (seeTable 1) Y = X = crack length at onset of fracture in mm W = stra
35、in energy A = fracture area W A - X B - Dimensions in millimetres Figure 1 Driving yoke and blade for initiating cracks in toughness specimensEN2155-21:1989 BSI 01-2000 5 Dimensions in millimetres Figure 2 Toughness specimen Dimensions in millimetres Figure 3 The fracture zones on a failed specimenE
36、N2155-21:1989 6 BSI 01-2000 Table 1 Values of Z Example: When Y = 0,146, Z = 0,0746 Y O 1 2 3 4 5 6 7 8 9 0,070 0,080 0,090 0,100 0,110 0,120 0,130 0,140 0,150 0,160 0,170 0,180 0,190 0,200 0,210 0,220 0,230 0,240 0,250 0,260 0,270 0,280 0,290 0,300 0,310 0,320 0,330 0,340 0,350 0,360 0,370 0,380 0,
37、390 0,0352 0,0403 0,0454 0,0505 0,0557 0,0609 0,0661 0,0714 0,0768 0,0822 0,0876 0,0931 0,0987 0,1044 0,1101 0,1159 0,1219 0,1279 0,1340 0,1402 0,1466 0,1531 0,1597 0,1665 0,1735 0,1807 0,1880 0,1955 0,2033 0,2113 0,2196 0,2281 0,2370 0,0357 0,0408 0,0459 0,0510 0,0562 0,0614 0,0667 0,0720 0,0773 0,
38、0827 0,0882 0,0937 0,0993 0,1049 0,1107 0,1165 0,1225 0,1285 0,1346 0,1409 0,1472 0,1538 0,1604 0,1672 0,1742 0,1814 0,1887 0,1963 0,2041 0,2121 0,2204 0,2290 0,2379 0,0362 0,0413 0,0464 0,0515 0,0567 0,0619 0,0672 0,0725 0,0778 0,0833 0,0887 0,0942 0,0998 0,1055 0,1113 0,1171 0,1231 0,1291 0,1352 0
39、,1415 0,1479 0,1544 0,1611 0,1679 0,1749 0,1821 0,1895 0,1971 0,2049 0,2129 0,2213 0,2299 0,2388 0,0367 0,0418 0,0469 0,0521 0,0572 0,0625 0,0677 0,0730 0,0784 0,0838 0,0893 0,0948 0,1004 0,1061 0,1119 0,1177 0,1237 0,1297 0,1359 0,1421 0,1485 0,1551 0,1617 0,1686 0,1756 0,1828 0,1902 0,1979 0,2057
40、0,2138 0,2221 0,2307 0,2397 0,0372 0,0423 0,0474 0,0526 0,0578 0,0630 0,0683 0,0736 0,0789 0,0843 0,0898 0,0953 0,1010 0,1067 0,1124 0,1183 0,1243 0,1303 0,1365 0,1428 0,1492 0,1557 0,1623 0,1693 0,1763 0,1836 0,1910 0,1986 0,2065 0,2146 0,2230 0,2316 0,2406 0,0377 0,0428 0,0479 0,0531 0,0583 0,0635
41、 0,0688 0,0741 0,0795 0,0849 0,0904 0,0959 0,1015 0,1072 0,1130 0,1189 0,1249 0,1309 0,1371 0,1434 0,1498 0,1564 0,1630 0,1700 0,1771 0,1843 0,1917 0,1994 0,2073 0,2154 0,2238 0,2325 0,2415 0,0382 0,0433 0,0485 0,0536 0,0588 0,0640 0,0693 0,0746 0,0800 0,0854 0,0909 0,0965 0,1021 0,1078 0,1136 0,119
42、5 0,1255 0,1315 0,1377 0,1440 0,1505 0,1571 0,1637 0,1707 0,1778 0,1850 0,1925 0,2002 0,2081 0,2162 0,2247 0,2334 0,2424 0,0387 0,0438 0,0490 0,0541 0,0593 0,0646 0,0698 0,0752 0,0805 0,0860 0,0915 0,0970 0,1027 0,1084 0,1142 0,1201 0,1261 0,1321 0,1384 0,1447 0,1511 0,1577 0,1644 0,1714 0,1785 0,18
43、58 0,1933 0,2010 0,2089 0,2171 0,2255 0,2343 0,2433 0,0392 0,0443 0,0495 0,0546 0,0598 0,0651 0,0704 0,0757 0,0811 0,0865 0,0920 0,0976 0,1032 0,1090 0,1148 0,1207 0,1267 0,1328 0,1390 0,1453 0,1518 0,1584 0,1651 0,1721 0,1792 0,1865 0,1940 0,2017 0,2097 0,2179 0,2264 0,2352 0,2443 0,0398 0,0449 0,0
44、500 0,0552 0,0604 0,0656 0,0709 0,0762 0,0816 0,0871 0,0926 0,0982 0,1038 0,1095 0,1154 0,1213 0,1273 0,1334 0,1396 0,1460 0,1524 0,1594 0,1658 0,1728 0,1799 0,1873 0,1948 0,2025 0,2105 0,2187 0,2273 0,2361 0,2452 X B -BSEN2155-21:1989 BSI 01-2000 National appendix A The United Kingdom participation
45、 in the preparation of 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 LimitedBSEN 2155-21:1
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