ASD-STAN PREN 2155-13-1989 Aerospace Series Test Methods for Transparent Materials for Aircraft Glazing Part 13 - Determination of Temperature at Deflection Under Load (Edition 1)《.pdf

1、A,E.C.M.A. STANDARD NORME A.E.C.M.A. A.E.C.M.A. NORM prEN 2155 Part 15 Edition 1 December 1989 EDIT PAR LASSOCIATION EUROPEENNE DES CONSTRUCTEURS DE MATRIEL AEROSPATIAL 88, boulevard Malesherbes, 75008 PARIS -TL. 45-63-82-85 UDC : Key words : ENGLISH VERSION Aerospace series Test methods for transpa

2、rent materials for aircraft glazing Part 13 - Determination of temperature at deflection under load Srie arospatiale Mthodes dessais pour matriaux transparents * pour vitrages aronautiques Partie 13 - Dtermination de la temprature de flchissement sous charge Luft- und Raumfahrt Prfverfahren fr trans

3、parente Werkstoffe zur Verlasung von Luftfahrzeugen Teil 13 - Bestimmung der Temperatur bei Durchbiegung unter Belastung This Aerospace series standard has been drawn up under the responsibility of AECMA (Association Europenne des Constructeurs de Matriel Arospatial). It is published on yellow paper

4、 in three equivalent versions (English, French, German). It will be submitted as a draft European Standard to CEN (European Committee for Standardization) for final vote. . I I . Approved by The equivalent versions in French and German languages can be supplied by B.N.A.E, 8, rue Moreau-Vauthier COM

5、ITE DE NORMALISATION of A.E.C.M.A. 1989-12-05 92100 BOULOGNE-BILLANCOURT - FRANCE I I prEN 2155-13 Page 2 Contents 1 Scope and field of application 2 Definitions 3 Apparatus 4 Specimens 5 Conditioning 6 Procedure 7 Test report AECMA PRENZL55-13 9 ia 2012312 0002279 prEN 2155-13 Page 3 1 1.1 This sta

6、ndard specifies a procedure for determining the temperature at which an arbitrary deformation occurs when the specimens are subjected to arbitrary bending loads, under conditions of continually rising temperatures. 1.2 The procedure applies to materials in sheet form in thicknesses 3 m. Scope and fi

7、eld of application - It does not apply to stretched/pressed (homogenous) acrylic materials. 2 Definitions For the purpose of this test the temperature of deflection under load is that temperature (attained during conditions of steady increase of temperature) at which a specimen of the material exhib

8、its a specified deflection. 3 Apparatus 3.1 shall conform to the description given below. The apparatus used is constructed essentially as shown in the figure 1 and 3.2 Specimen supports The specimen rests horizontally on metal supports (see figure 1); the load is applied vertdcally on the upper fac

9、e of the specimen at midway between supports by means of a rod. The vertical members, which attach the specimen supports to the upper plate are made of material having the same coefficient of linear expansion as is used for the rod (see note). Note : Unless these parts have the same coefficient of l

10、inear expansion, the differential change in length of these parts introduces an error in the reading of the apparent deformation of the specimen. A blank test is made on each apparatus wng a test bar made of rigid material having a low coefficient of expansion . All temperature ranges to be used sha

11、ll be covered and a correction factor is determined for each temperature. If the correction factor is 0,010 mm or greater, its algebraic sign is noted and the factor is applied to each test by adding it algebraically to the reading of apparent deflection of the tested specimens. 1) Invar or borosili

12、cate glass has been found suitable for this purpose. prEN 255-13 Page 4 3.3 Immersion bath The specimen is immersed in a suitable liquid heat-transfer medium (see note). The bath is well stirred during the test and provided with a means of raising the temperature at an average rate of 2 C/min and th

13、e temperature shall not deviate from the average by more than - + 1 OC at any time measured over periods of 5 min. Note : A liquid heat-transfer medium is chosen which is stable and which does not affect the specimen at the temperatures used. 3.4 Weights A set of weights of suitable sizes is made av

14、ailable so that the specimen can be loaded to a fibre stress of 1,8 ma. The weight of the rod which applies the testing force is determined and included as part of the total load. If a dial gauge is used, the force exerted by its spring is determined and included as part of the total load (see notes

15、 1 and 2). The load is calculated from the following formula : 2 O-B d2 31 F= where : F = Total load in N of the rod and weights with due allowance for any force exerted by the spring of a dial gauge r = 1,8 MPa B = Width of specimen in mm d = Depth of specimen in mm 1 = Width of span between suppor

16、ts in mm, The actual load applied is the calculated load -i- 2,5%. The dimensions of the cross-section of the specimen used in the calculation are measured to the nearest 0,02 mm. The space between supports is measured to the nearest 0,l mm. Note 1 : In certain forms of the apparatus, the force of t

17、he dial gauge spring is directed upward and shall be subtracted from the load, while in other forms this force acts downward and shall be added to the load. Note 2 : Since the force exerted by the spring in certain dial gauges varies considerably over the stroke, this force is measured in that part

18、of the stroke which is to be used. - AECMA PREN2L55-13 7 W 10L23LL 0002301 2 W prEN 2155-13 Page 5 3.5 Thermometers The thermometer is a mercury in glass thermometer of the partial immersion type, graduated in OC. The graduation marks shall permit reading 1 OC and the scale error at any reading shal

19、l not exceed 0,5 OC. The thermometers are immersed to the depth for which they have been calibrated and which shall be at least 50 mm. 3.6 Preparation of apparatus The apparatus is arranged so that the deflection of the midpoint of the specnen can be measured on a scale calibrated in hundredths of 1

20、 mm. The apparatus may be arranged to shut off the heat automatically and sound an alarm when the deflection specified in the table has been reached. 4 Specimens 4.1 At least two specimens are used to test each sample. The specimens are at least 110 mm in length, between 3,O mm and 13,O mm in width

21、and between 10,O mm and 13,O mm in depth, The specimens are cut from sheet material as indicated in figure 2 their width corresponding to the thickness of the sheet. 4.2 If the thickness of the sheet exceeds 13,O mm the width of the specimens shall be reduced to 13,O mm by machining of one face, the

22、 other face being left untouched. 5 Conditioning The specimens shall be conditioned in an air circulating oven for 48 hours at (80 2) OC, followed by cooling to room temperature in a desiccator until tested. 6 Procedure The specimenis placed in the apparatus the load being applied as shown in figure

23、s 1 and 3. The thermometers extend to within 10 mm of the specimen but shall not touch it. The temperature of the bath shall be 20 OC to 23 OC at the start of each test, unless previous tests have shown that, for the particular materials under test, no error is introduced by starting at other temper

24、atures. The load is adjusted to give a fibre stress of 1,8 MPa, as calculated by the formula given in clause 3.4. The load is allowed to act for 5 min (see note) the zero reading or setting of the measuring device is then made and the heating started. Tests are conducted by raising the temperature o

25、f the bath, as required it: clause 3.3. The temperature at which the bar has reached the arbitrary deflection as given in the table is recorded as the temperature of deflection under load at 1,8 MPa fibre stress. AECMA PREN2L55-13 87.m 10L231L 0002302 4 prEN 2155-13 Page 6 Table - Deflections Dimens

26、ions in millimetres Note : Depth d 10,O to 10,39 10,4 to 10,69 10,7 to 10,99 11,O to 11,49 11,5 to 11,99 12,O to 12,39 1234 to 12379 12,8 to 13,O Deflection 0,32 0,31 0,30 0,29 0,28 0,27 0,26 0,25 The 5 min waiting period is provided to compensate partially for the creep exhibited by certain materia

27、ls at room temperature when subjected to the .prescribed fibre stress. That part of the creep which occurs in the initial 5 min is usually a large fraction of that which occurs in the first 30 min. This waiting period may be omitted when testing materials which show no appreciable creep during the i

28、nitial 5 min. 7 Test report The test report shall include : - reference to this standard, - D ana a or tne specimens measured to the nearest 0,02 mm, - fibre stress, the temperature of deflection under load for each specimen in C and the - the nature of the immersion medium, - any peculiar character

29、istics of the specimens noted during the test or after removal from the apparatus. AECMA PREN2155-LI 7 81 LOL23LL 0002303 b prEN 2155-13 Page 7 Dimensions in miiiimetres IOOI 2 IL L (Length of specimen) Figure 1 - Apparatus for determinationeof temperature at deflection under load AECMA PRENZL55-L3 87 E lt01i23LL 0002304 8 U prEN 2155-13 Page 8 B = width of specimen = thickness of sheet d .= depth of specimen Figure 2 - Sampling from sheet Figure 3- Specimen and load application