1、AECNA PREN2747 70 E 1012311 0004071 5 W 1- I A, E. CI M. A. STAN DAR D prEN 2747 NORME A.E.C.M.A. Issue P 1 A.E.C.M.A. NORM August 1990 Edition approved for publication 1990-08-24 DIT PAR LASSOCIATION EUROPENNE DES CONSTRUCTEURS DE MATRIEL AROSPATIAL 88, boulevard Malesherbes, 75008 PARIS -TL. 45-63
2、-82-85 UDC : Key words : Comments should be sent within six months C7 Chairman after the date of publication decision A.E.C.M.A. 88, Bd. Malecherbes Mr. BEZAUD 75008 PARIS - FRANCE ENGLISH VERSION Aerospace series Glass fibre reinforced plastics Determination of tensile properties Srie arospatiale L
3、uff- und Raumfahrt Matires plastiques renforces au verre textile Dtermination des caractristiques en traction Glasfaserverstrkte Kunststoffe Zugversuch This Aerospace Series pre-standard has been drawn up under the responsibility of AECMA (Association Europenne des Constructeurs de Matriel Arospatia
4、l). It is published on green paper for the needs of AECMA-Members. It has been technically approvedby the experts of the concerned 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 int
5、erchangeability 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 C
6、EN (European Committee for Standardization) for final vote. 0 aecrna 199 _ AECMA PREN2747 90 M 1012311 0004092 7 M prEN 2747 Page 2 Content s 1 2 3 4 5 6 7 8 9 10 Scope and field of application Eeferences De.f initions Designation of the method Apparatus lest specimens Ccnditioning Procedure Calcula
7、tions and expression of results Test report I AECMA PREN27Li7 90 a LOLZ3LL _ 0004073 7 a I prEW 2747 Page 3 1 Scope and fielcl of application 1.1 This standard specifies a method for the determination of tensile properties of glass fibre reinforced plastic materials. The method is applicable to rein
8、forced thermosetting resins and equally to reiiif orced thermoplastic resins. The results from injection nioulded test specimens fron: glass fibre reinforced therxoplastics are mainly influenced by the orientation of the fibre. This manufacturing method may be used, when other methods for manufactur
9、ing test specimen are not possible. 1.2 This method enables the following tensile properties to be determined : - tensile strength at break, - tensile moduli of elasticity, - elotigat ions. 2 References EW 2374 Aerospace series - Glass bre reinforced mou composites - Production of test panels ings a
10、nd sanciw,:h EN 2489 Aerospace series - Fibre reinforced plastics - Determination of the action of liquid chemicals 1) EN 2743 Aerospace series - Bein.forced plastics - Standard atmospheres for corditioning and testing 2) EN 2823 Aerospace series - Fibre reinforced plastics - Test method for the det
11、ermination of the effect of exposure to humfd atmosphere on physical and mechanical characteristics 2) 3 Definitions 3.1 Tensile stress Tensile load borne by the test specimen throughout the test, per unit initial cross sectional/area of the straight portion of the specimens. 3.2 Elongation Increase
12、 in distance between reference-marks on the straight portion of the test specimen prodiiced by a tensile load and expressed as a percen.tage of the initial distance between the ref erence-marks . 1) Published as AECMA pre-standard at the date of publication of the present standcrd 2) In preparation
13、at the date of publication of the present standard AECMA PREN2q 90 LOL23LL OOOqO7q O 9 psEh 2747 Pc,ge 4 3.3 Modulus of elasticity Quotient of the tensile stress and the corresponding relative deformation in the ultimate maximum strain that a material can bear without deviating from the proportion d
14、eformation-stress, that is the grdient of the relative stress/deformaticn diagram obtained in a tersile test. When the ultimate proportion is exceeded or when it does not exist, it is necessary to distinguish : 3.3.1 Initial tangent modulus Gradient to the tangent at the zero point (see note) of the
15、 relative load /apparent st rain diagram. Note : With certain types of equipment, it may happer. that the diagrams obtained show local irregularities at the outset which must be discounted when. plotting the tangent. There are grounds in this cace when measuring the change in length, for correcting
16、the zero point (see figure 2). 3.3.2 Secant modulus to x 2 elongation Grsdient of the straight line going through the zero point 1) of the stress/deformation diagram and the point in this diagram which corresponds to a relative change in length of x %. 4 Designation of the method Example : In case t
17、he test has been carried out with specimen type I. Description block Identity block Tensile properties EN2747-I Title description Number of the EN standard Type of specimen according to table 1 5 Apparatus 5.1 Test machine with constant tensile speed and comprising : a) A fixed or in practice fixed
18、part, with a suitable grip and a mobile part with a second grip. The grips shall.be designed so as to enable the axis of the test specimens to be aligned at all times with the direction of the applied force. Thh can be achieved, for example, by using centring rods in the jaws of the test: machine, 1
19、) The zero point being taken after possible correction according to the note to clause 3.3.1. b) A load indicating mechanism. It is essential that this mechanism has no inertia at the test speeci and it shall indicate the load to an accuracy of at least 1 % of the value indicated. The fixed and mobi
20、le parts, the device mechanisni and the grips shall be constructed from materials and In sizes such that the total elastic longitudinal deformation of these devices does not exceed 1 Z of the longitudinal deformation sustained at the time of the test compared to the reference length of the test spec
21、imen; these requirements shall be satisfied for any load whatsoever that is less or equal to the fixed capacity of the test machine. 5.2 Extensometer It shall enable determination at any time during the test of the distance between two fixed points (or reference-marks) situated on the straight porti
22、on of the test specimen, Note 1 : Also applicable are mechanical, optical or volumetrical devices, if they measure the elongation of the test specimen to an accuracy of at least 1 %. Note 2 : test specimen not cause failures in the grips. The extensometer used shall not give rise to any damage to th
23、e The initial distance between the - two ref erence-marks, called “gauge length“, shall be known to within an accuracy of 5 1 %. The change in length shall be recorded automatically in relation to the load or the time elapsed since the start of the test, In this latter case, one shall equally record
24、 the load in relation to time. It is essential that the extensometer has no inertia at the test speed. It shall be accurate to within at least 1 X of the elongation measured. The reference length recommended is to be taken from table 1. However, a shorter distance can be used, as long as the above t
25、olerances are adhered to. 5.3 MicronLeter The micrometer shall have an accuracy of 5 0,Ol mm. ci 6.1 The agre Test specimens Preparation types are acco .ed between user trding and ma to table 1; .nufacturer. mat er ia 1 related requirements shall be I F Minimum total 1er.gth W Width of ends 150 20 +
26、 - 0,5 h t hi ckne s s of specimens semi-finished products 2 to 10 test panels 2 to 3,5 according to EN 2743 B Length of straight portion b Width of straight portion Lo Gauge length 60 i- - 0,5 10 + - 0,5 50 E Distance between grips D Distance between tabs 115 2 5 - T Minimum length of tabs P Diamet
27、re of centring holes e Thickness of tabs - - - ,AECMA PREN2747 O L0123Ll O004096 4 prEN 2747 Page 6 Table 1.- Dimensions for the test specimens according to figure 1 Dimensions in millimetres I Type II Type III Type IV I 250 164 - - 2 to 10 250 2 to 10 2 to 3,5 2 to 3,5 1 + 0,2 to I 3-+ - 0,2 - I 25
28、 + - 0,5 25 + - 0,5 10 -i- - 0,5 1 50 or 100 50 or 100 I 25 170 + - 5 1 50 2 2 170 5 5 150 + 5 I 64 i- 1,5 50 50 + 0,25 - 0,05 + 0,25 - O,G5 + 0,25 - 0,05 0,5 i- I 0,l Especially applicable for Glass f ab reinf therm fibre 8ic med Gets Unidirect ional glass fibre reinforced thermosets Glass fibre re
29、inforced thermo- plastics *. AECMA PREN2747 70 H LL23LL 0004077 b - prEN 2747 Page 7 E h I I f I ! F c TYPE I 2 HOLES 0 P DRILLING OF HOLES OPTIONAL) E I NPE II y fb!?g:t it is recommended that a cooling fluid he used. In this case make sure the test specimen is .ciiped dry immediately after machini
30、ng. - Check that the edges of the test specimei; are free of defects, 6.1.3.1 Type I test specimens The test specimens of reinforced thermoplastbc 2re usually prone to fibre misalignments, when they are moulded. It is, therefore, desirable in most cases to machine test specimens from coinpression-mo
31、ulded rectangular sheets with an abrading wheel or mill of suitable naterial, using a template. 6.1.3.2 Rectangular test specimens type IS iip to and including type IV These may be cut using di.amond cr silicon carbide saws. 6.2 Number of tcst specimens Beinforced plastics are generally misotropic.
32、It is, therefore, often worth cutting the test specimens along at least the two principal anisotropic directions cr according tc previously specified directions (for example longitudinally or crosswise to the sheet). . For each direction and property that is being considered (modirlus of ehsticity,
33、tensile strength, etc.) at,least five valid results AK necessary. Reject and replace any test specimen tliat has broken in the jaws or nt less than 10 mm from the jaws. 7 Conditioning In case the test is carried out in the initial state, the specinens shall be conditione according to EN 2743, In cas
34、e the test is carried out after immersion of the test spcdmens, the conditioning shall be according to EN 2489. In case the test is carried out after hot-wet exposure of the test specimeris, the conditioning shall be according to EN 2823. 8 Procedure 8.1 Test atrtiosphere Unless otherwise specified,
35、 carry out the testu Kt (23 + -_ 2) “C and (SO i- - 5) W relative humidity. 8.2 kleasurerrient of the dinensions of the test specimns Measure the wideli 1; to the nearest U,1 mm and the thickness h to the nerest 0,OZ mm, this beiig tc the centre of the test specimen and at a distance of 5 mm from ea
36、ch end of the gauge Length, in the directior; of the centre. 8.3 Eecording c?r:d calculetion of the widths and thicknesses I 91 Tensile stress at bs6:alc Calculate the tensile stress at break with the help of the following formula : Record the urininum und maximum values of width and thickness and m
37、ake sure that for the width they are within the tol.erances given in table 1. Calculate the arithmetical mean of the widths b ar,d thicknesses h of the respective ceasured specimen type which is to be used for calculation. - 8.4 Test techniques Place the test specimen in the grips, taking care to al
38、ign the 1orgitudinal.axis of the test specimn with the mechanical axis of the test machine. When the centring rods in the grips are vsed, perfect alignment is obtained by light: tension cn the test specimen before clamping the grips together. Clamp uniformly and strongly to avoid any slipping of the
39、 test specinien. Check and, if required, calibrate the extensmeter. Fix the extensometer in the centre of the test specimen. 8 Note : If a tensile load has been appliet: during clamping in the grips, reduce this to zero before measuring strain. . The testing speed for all types of test specimens sha
40、ll be 2 m/miri -i- - 10 %. 9 Calculations and expression of results where : bh o is the temile stress at break in MPa F is the maximum fcrce in N b is the initial average width of the test specimen, in m: h is the initial average thickness of the test specimen, in mm. Record the result to three sign
41、lficant figures. e prEN 2747 Page 12 AECMA PREN2747 90 m 1012311 0004102 b W 9.2 Strain at maximum load Calculate the strain at maximum load, as a percentage, using the formula : c . Lo LO where : a is the strain at niaxinum load in X Zr is the apparent elongation at maximum load (see note), in mm,
42、measured on the loa.d/elongation curve (see figure 2) C is the magnification of the extensometer Lo is the gauge length of the extensometers in mm. Note : The apparent elongation at maximm load is the direct reading from the graph, in mu, without correcting for the magnification of the extensometer.
43、 Record the result to two significant figures. 9.3 1nitia.l tangent modu1u.s of elasticity Calculate the initial tangent inoddus of elasticity usin.g the following formula : 1, O . C .AF1 A . bZ, - Er - o where : Er is the initial tangent rnodulus of elasticity under tension, in MPa AF, is the chang
44、e in force in N (see figure 2) Lo is the gauge length of the extensometer, in mm C is the magnification of the extensmeter A dZ1 is the cross-sectional area of the straight portion of the specimen in mm2 is the change in length, 2n nun, measured on the curve for the change in load a F1 (see figure 2
45、) Note : It is suggested to determine the secant modulus of elasticity to 0,l X change in length instead of the initial tangent modulus of elesticity, when the latter cannot be determined and to take it as the initial tangent modulus of elasticity. O Record the result to three significant figures. F
46、INI Fr - v AECMA PREN2747 90 m LOL231L 0004103 m prEN 2747 Page 13 Correction I at origin -Z if required) 1. Initial tangent . . I l Secant at x X I I I I I I I 1 1 I I 1 1 1 I I I I I A I I * 1 I I I I I I I l I I LL 1 Figure 2 - Curve of apparent (Z) with lod (F) I AECMA PREN2747 90 LOL231L 00041
47、04 T m prEN 2747 Page 14 a 9.4 Secant modulus of elasticity in tension Calculate the secant modulus of elasticity in tension corresponding to a strain of x Z by means df the following formula : where : is the seccnt modulus of elasticity in tension, in MPa, corresponding to a strain of x 2 (it is re
48、commended to use 0,5 2 strain) Ex bF is the chapge in force, in If, corresponding to a strain of x Z (see figure 2) x Lo C A is the initial crocs-secticnal area of the straight portion of the test is the gauge length of t3k extensometer in mm is the magnification of the extensometer o O specimen, in
49、 II-E is the chaqe in ler,gth, in mm, mewaired on the curve for the change in load A F AZ (see figure 2) o x X Record the resiilt to three significant figures. 10 Test report The report shall refer to this stafidard and merition the following infcrmation : 10.1 Full identification of the product which has undergone test, iiicluding identification of its types, origin, numerica codirig of the manufacturer, shape, main dimensions, previous treatment etc. 10.2 Type of test specimen : average minimum an maximum
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1