1、- STD-AECMA PREN 2bb7-2-ENGL L79b 9 1012311 OOL2787 87Li m AECMA STANDARD NORME AECMA AECMA NORM prEN 2667-2 Edition P 1 November 1996 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Gulledelle 94 - 6-1 200 BRUXELLES - Tel. (32) 2 775 81 10 - Fax. (32) 2 775 81 11 tcs : Descrip
2、tors : ENGLISH VERSION Aerospace series Non-metallic materials Foaming structural adhesives Test methods Part 2 : Compressive tube shear Srie arospatiale Luft- und Raumfahrt Matriaux non-mtalliques Nichtmetallische Werkstoffe Adhsifs structuraux expansibles Strukturelle Expansionsklebstoffe Mthodes
3、dessai Prfverfahren Partie 2 : Cisaillement sur tube en compression Teil 2 : Abscherung von Rohren unter Druck This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECMA /The European Association of Aerospace Industries). It is published on green paper for the needs of A
4、ECMA-Members. It has been technically approved by the experts of the concerned Technical Committee folio wing comment by the Member countries. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physically or
5、 functionally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Centre (NPSI and formal agreement of the Official Services of the Member countries it will be submitted as a draft European Standard to CEN balance with an accuracy to the nearest
6、 0,Ol g ; band saw ; thermoelectric couple ; mounting device per figure 1. 1 ) Published as AECMA Standard at the date of publication of this standard 2) Published as AECMA Prestandard at the date of publication of this standard Previous page is blank Page 4 prEN 2667-2 : 1996 4 Test tubes, test spe
7、cimens 4.1 Test tubes The shape and the dimensions of the concentric tubes shall be in conformity with figure 2. 4.1.1 Materials The following materials are normally to be used : aluminium alloy 2024 - T351, in accordance with EN 2338, or ; aluminium alloy 5052-0, in tubes for structures 0,6 mm I a
8、I 123 rnm. For test temperature exceeding 150 OC, the same aluminium alloys shall be used after verification of their test temperature capability. 4.1.2 Surface preparation Surface preparation before bonding shall be in accordance with EN 2334. 4.1.3 Bonding of the test tubes shall take place within
9、 4 h after completion of the preliminary surface treatment. The test tubes may require application of a primer to ensure cohesive failure, .e. failure within the adhesive. The application of the foaming adhesive system (adhesive and primer, if necessary) as well as the curing shall be carried out in
10、 accordance with the adhesive manufacturers instructions and the material standard. The tubes shall be weighed to the nearest 0,Ol g : ml, m2. A mass m3 of adhesive 1) defined in the material standard, or in line with the manufacturers recommendation, shall be rolled or spread evenly over the entire
11、 surface of the inner tube. The two tubes (length between 100 mm and 230 mm) shall then be assembled using centering caps (see figure 3) with the interposition at both ends of a temperature resistant washer made out of knitted fabric (stitches of approximately 100 pm) to retain the adhesive while al
12、lowing air and reaction gases to escape. The curing process shall be carried out with the tube in a horizontal position and according to the material standard. The heat-up rate of the test tubes shall range from 1 OC/min to 6 OC/min and shall be monitored and recorded using a thermoelectric couple p
13、laced in the adhesive at the end of the test tubes. After the end of the cure, cool the test assembly until it reaches ambient temperature. Then remove the curing assembly described in figure 3 and disassemble to obtain the test tubes. The test tubes shall be weighed to the nearest 0,Ol g : m4. Bond
14、ing and weighing of test tubes 4.1.4 Storage of test tubes after curing The final test tubes shall be conditioned and tested after a storage period of at least 16 h after curing and under the following conditions : - temperature : (23 k 2)OC - relative humidity : (50 i 5)%. 1) The determination of t
15、his mass m3 depends on the density, on thickness and on the expansion ratio of the adhesive as well as on the length of test tubes. STD*AECflA PREN Zbb7-2-ENGL 177b 103233L 0032792 3b7 W Page 5 prEN 2667-2 : 1996 4.2 Test specimens 4.2.1 Cutting test specimens The cutting of the test tubes into test
16、 specimens shall be done with an appropriate tool such as a band saw, in accordance with figure 2. The number of teeth and the set of the saw as well as the feed and cutting speed shall be chosen so to minimize thermal and mechanical stressing. The cuts shall be plane and perpendicular to the tube a
17、xis and no cooling fluid shall be used. It is possible to obtain five test specimens per test tube of 100 mm and fifteen test specimens per test tube of 230 mm, while discarding a minimum of 10 mm at each end. Each test specimen shall be identified with an individual reference mark so as to locate t
18、he number of the test tube from which it originated as well as its position in this tube. 4.2.2 Quantity There shall be a minimum of five individual test specimens for each test. 5 Procedure Tests shall be performed at the temperatures specified in the material standard. For all tests carried out at
19、 a temperature other than ambient the heat-up rate or the cooling rate of the test specimen shall be less than 10 OC/min. Load shall be applied after stabilization at the specified temperature for a minimum of IO min and a maximum of 30 min (unless otherwise specified by the supplier). For all tempe
20、ratures, with the exception of ambient temperature (23 I 2) OC, the temperature of the test specimen shall be measured by means of a thermoelectric couple, fixed to the outer surface of the test specimen in accordance with figure 1. The test set-up (see figure 1) comprises a cylindrical ram and a ba
21、se acting as spacers. The supports shall be vertically centred in respect to the test specimen so that the external ring rests fully on the support base. Bond strength shall be determined by shearing the inner tube downward with the test set up as shown in figure 1. The load of the test specimen sha
22、ll be applied at a constant rate ranging from 2 O00 N/min to 5 O00 N/min until failure. STD-AECMA PREN 2bb7-2-ENGL 397b 30323LL 0032793 2T5 W Page 6 prEN 2667-2 : 1996 6 Expression of results Calculate the bond strength for each test specimen as follows : F max. n.d,.h T= where : T F rnax. h is the
23、shear strength on tubes, in megapascals ; is the maximum load, in newtons ; is the outside diameter of the inner tube, in millimetres ; is the height of the test piece, in millimetres. dl Dimensions d and h shall be measured to within i 0,l mm. Calculate the average bond strength of the series of te
24、st specimens. Calculate the density of the foam adhesives to the nearest 0,Ol g/cm3 as follows : 4 000. (m4 - (m, + m*) D= L. n. (d 2 - d :) where : is the tube density, in grams per cubic centimetre ; is the outer tube mass, in grams ; is the inner tube mass, in grams ; is the mass of test tubes, i
25、n grams ; is the length of the tubes, in millimetres ; is the outside diameter of the inner tube, in millimetres ; is the inner diameter of the outside tubes, in millimetres. 7 Designation EXAMPLE : EN2667-2 I Number of this standard 8 Test report It shall include the following : - reference to this
26、 standard ; - complete identification of the foaming adhesive and primer if any, including the type, name and address of the manufacturer, date of manufacture, batch number and material standard number ; - storage conditions of the foaming adhesive before curing (temperature, humidity) ; - complete
27、identification of the metal used and its surface preparation, including storage up to the bonding ; - processing and curing conditions (equipment, heat-up rate, curing temperature, duration and record of temperature) ; Page 7 prEN 2667-2 : 1996 - number of test specimens ; - test conditions and temp
28、erature ; - type of test machine, selected capacity and rate of load application ; - information on each test specimen including reference mark of the test specimen, the dimensions, failure load, bond strength, and density of the test tube from which the test specimen were cut ; - the type of failur
29、e in cohesion or adhesion for the adhesive and any primer ; - the average minimum and maximum tube shear strength ; - any deviation from this standard in detail ; - date of test and signature. STD-AECMA PREN 2bb7-2-ENGL L77b 30L23LL 0032775 078 Page 8 prEN 2667-2 : 1996 Dimensions in millimetres N L
30、I I Base #12,7 f 0,l t-i Ram Test tooling Ram 6 Test piece Test mounting Figure 1 STD-AECMA PREN 2bb7-2-ENGL L77b LOL23LL 003277b TO4 m II Il Page 9 prEN 2667-2 : 1996 II I II I Dimensions in millimetres II I Dimensions of coaxial tubes 25.4 * 0.1 C F h i E 4 C C .- E Test piece Figure 2 Page 10 prEN 2667-2 : 1996 Dimensions in millimetres A-A - A T I 7 +- e Thermoelectric couple Foam inner tube External tube 4 7 3 TA Test tube with k cure assembly Figure 3 : Centering system
