1、A. E. C. M. A. STAN DARD NORME A.E.C.M.A. A.E.C.M.A. NORM Edition approved for publication Comments should-be sent within six months after the date of publication decision 88, Bd. Malesherbes 25th April 1989 A.E.C.M.A. 75008 PARIS - FRANCE prEN 2562 Issue P 1 April 1989 C7 Chairman Mr BEZAUD EDITE P
2、AR LASSOCIATION EUROPENNE DES CONSTRUCTEURS DE MATERIEL AEROSPATIAL 88, boulevard Malesherbes, 75008 PARIS -TL. 45-63-82-85 UDC : Key words : ENGLISH VERSION Aerospace series Unidirectional laminates carbon-thermosetting resin Flexural test Srie arospatiale Stratifis unidirectionnels carbone-rsine t
3、hermodurcissable Essai de flexion Luft- und Raumfahrt Unidirektionale Kohlenstoffaser- Duroplast-Verbundwerkstoffe Biegeprf ung This Aerospace Series pre-standard has been drawn up under the responsibility of AECMA (Association Europenne des Constructeurs de Matriel Arospatial). It is published on g
4、reen paper for the needs of AECMA-Members. It has been technically approved by the experts of the concerned AECMA Commission following comment by the Member countries. Subsequent to the publication of this pre-standard, the technical content shall not be changed to an extent that interchangeability
5、is affected, physically or functionally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Centre (NPS) and formal agreement of the Official Services of the Member countries it will be submitted as a draft European Standard to CEN (European Com
6、mittee for Standardization) for final vote. AECMA PREN2562 A7 W 10I231I 0003517 I prEN 2562 Page 2 Issue P 1 Contents 1 2 3 4 5 6 7 8 9 10 11 12 Scope and field of application References Definitions Principle of the method Designation of the method Test specimens Apparat us Conditioning Procedure Te
7、st results Expression of results Test report AECMA PREN2562 87 L0123LL 03520-8 H prEN 2562 Page 3 Issue P 1 1 Scope and field of application This standard defines the method for the determination of flexural strength and modulus of unidirectional carbon-thermosetting resin laminates by a flexural te
8、st. This method is restricted to specimens in which the length is parallel to the fibre direction. Note : The elastic modulus measured by this method shall only be considered as an approximate value for YOUNGS modulus. 2 References EN 2489 Aerospace series - Fibre reinforced plastics - Determination
9、 of the action of liquid chemicals 1) EN 2565 Aerospace series - Preparation of carbon fibre reinforced resin panels for test purposes 1) EN 2743 Aerospace series - Fibres reinforced plastics - Standard atmospheres for conditioning and testing 2) EN 2744 Aerospace series - Non-metallic materials - P
10、referred test temperatures 2) EN 2823 Aerospace series - Fibre reinforced plastics - Exposure to humid atmosphere - Parameters for conditioning and testing 2) 3 Definitions 3.1 Deflection (f) The distance moved during flexing by the upper or lower face of the specimen at the centre of its span compa
11、red to its initial position. 3.2 Flexural stress at a given moment during the test The maximum stress of the external fibres of the material in the middle of the span of the specimen between the supports. It is calculated according to the generalformula given in clzuse 11.1. 1) Published as AECMA pr
12、e-standard 2) In preparation AECMA PREN25b2 87 LOL23LI 0003523 T prEN 2562 Page 4 Issue P 1 3.3 Flexural strength at failure (b) The flexural stress at moment of failure. 3.4 Secant modulus at P 12 (Eb) The slope of the straight line passing through the relative stress/strain curve at a point corres
13、ponding to a stress calculated for P /2 aiid a point on the same curve corresponding to a stress calculated for P /lo, P is the failure load of the specimen. R R R R It is calculated according to the formula given in clause 11.2. 4 Principle of the method During a flexural test carried out at consta
14、nt speed until failure, the deflection at the loading nose is measured as a function of the applied load and the longitudinal relative strain calculated as a function of the applied stress, The specimen is held over a span sufficiently large that the failure does not occur in shear and strains due t
15、o shear loads may be neglected. 5 Designation of the method The designation of the method shall be drawn up according to the following example. Description block dentity block I Example : Flexural test Number of standard - Type of specimen (see sub-clause 6.1) 6 Test specimens The test specimens are
16、 taken in panels prepared according to EN 2565. AECMA PREN2562 89 W L0123LL 0003522 L mp - prEN 2562 Page 5 Issue P 1 6.1 Form and dimensions of specimens Figure 1 - Specimen and test fixture Dimensions in millimetres Symbols - width =b distance between supports = thickness of specimen 1) = h r r le
17、ngth =L loading nose radius - support radii - lV 1 2 10 + 0,2 80 3 0,5 12,5 0,l 100 T 1 2 7 0,2 5 3 - 0,l 10 + 0,2 60 T 1 50 7 0,5 12,5 3 0,l 2 T 0,2 5 z 0,l I 6,2 Number of specimens Use at least 5 specimens. 1) If the layer thickness may lead to uncertainty regarding the number of layers required
18、to obtain material of thickness (2 +- 0,2) m, the number of layers should be stated in the relevant standard for the product. AECMA PREN2562 B7 LOL23LL 0003523 3 prEN 2562 Page 6 Issue P 1 7 Apparatus 7.1 Test fixture See figure 1. The test jig shall ensure an accurate positioning of the specimen. T
19、he misalignment between loading nose arid supports shall not exceed 0,l mm. 7.2 Micrometer fitted with 6 mm diameter flat measuring faces, accurate to within 0,Ol mm. 7.3 Test machine accurate to within 1% in the load range used. 7.4 Device for recording the deflection as a function of load accurate
20、 to within 1% in the deflection range used. 7.5 for tests at temperatures other than ambient. Where required, a temperature chamber controlled so as to conform to EN2744 7.6 Thermocouple and recorder for tests at temperatures other than ambient. 8 Conditioning In case of tests in the initial conditi
21、on, the conditioning shall be in accordance with EN 2743. In case of tests after immersion, the conditioning shall conform to EN 2459. In case of tests after exposure to moist heat, the conditioning shall conform to EN 2823. 9 Procedure 9.1 Make 3 different measurements of the thickness and the widt
22、h of the specimen to within 0,Ol mm and calculate the mean value. Measure the distance between supports to within 0,l m. e a O O AECMA PREN2562 7 LOL2321 000352Li 5 prEN 2562 Page 7 Issue P 1 9.2 For tests at temperatures other than ambient, the period separating the conditioning and start of the te
23、st shall conform to the following conditions : 9.2.1 For Specimens which have not been aged or subjected to immersion the hold time at the test temperature shall be established by preliminary experiment and shall be noted in the test report. 9.2.2 For specimens subjected to immersion, follow the pro
24、cedure described in EN 2489. 9.2.3 For humidity aged specimens, follow the procedure described in EN 2823. 9.3 Locate the test specimen in the test jig, with the specified face in contact with the loading nose, ensuring that its axis is perpendicular to the supports. If the face in contact with the
25、loading nose is not specified, record its type (for instance mold side, bag side, .). 9.4 The load shall be applied at a constant rate : - - 9.5 Record the deflection f with respect to load. of 5 mm/min for specimen with span between supports 1 of 2 mm/miii for specimen with span between supports 1
26、of 80 mm of 50 mm. V V 9.6 Record the load at failure PR. 10 Test results The test is only considered to be representative for .the flexural properties of the material if the break is in tension or compression. Failures in a shear mode have to be excluded. Examples : c - 1 Tensile (valid) c -. Shear
27、 (not valid) - Compression (valid) I AECMA PREN25b2 89 1012311 0003525 7 prEN 2562 Page 8 Issue P 1 11 Expression of results 11.1 Strength at failure (6 ) in ma b 6b = 3.PR. lV 2.b.h2 where : load at failure, in N R b : width, in mm h thickness, in mm lV : distance between supports, in mm. 11.2 Seca
28、nt modulus at PR/2 Measure on the load/deflection record. (E ).in MPa b “4 pR . iV3 Eb = 10 . b . hS . (f2 - fi) where : load at failure, in N R : b : width, in mm h thickness, in mm lV : thickness between supports, in mm fl : deflection corresponding to PR/lO, in mm E2 : deflection corresponding to
29、 PR/2, in mm. AECMA PREN2562 89 LOL23LL 000352b_-7_j prEN 2562 Page 9 Issue P 1 12 Test report The test report s,al include the following information : 12.1 Nuinber of this standard, brand, identification mark, origin, date of receipt and further data of the tested material. 12.2 Data about the prep
30、aration of the test Specimens. 12.3 Measured dimensions of the test specimens (type of specimen chosen), arid face in contact with the central loading nose. 12.4 A graph representing the load measured as a function of deflection. 12.5 When test specimeiis have been broken in flexure (tension or comp
31、ression failure) record the individual values, the arithmetic mean, the standard deviation of the flexural strength at failure 6 b 12.6 When the test specimens have not been broken in flexure (tension or compression failure), the type of failure shall be described, specifying in an appended note tha
32、t the calculated stresses are according to paragraph 11.1 and are lower than the flexure strength at failure. 12.7 Record the individual values, the arithmetic mean, the standard deviation of the secant modulus at PR/2 (E ). b 12.8 Test conditions i.e. temperature and relative humidity deviating from the standard. 12.9 Period of soak at the test temperature, for tests after immersion (see EN 2489), or exposure to htinid atmosphere (see EN 2823). 12.10 Observations on any circumstances liable to influence the results.
