1、AECMA PREN*b031 95 10L23LL 0009974 b9B W Edition approved for publication Comments should be sent within SIX months after the date of publication to AECMA STANDARD NORME AECMA AECMA NORM AIBITFG Chairman prEN 6031 Edition P1 November 1995 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES
2、 (AECMA) Gulledelle 94 - B-1200 BRUXELLES - Tel. (32) 2 775 81 1 O - Fax. (32) 2 775 81 11 ICs : ENGLISH VERSION Aerospace series Fibre reinforced plastics Test method Determination of in-plane shear properties (+ 45O tensile test) Srie arospatiale Matires plastiques renforces de fibres Mthode dessa
3、i Dtermination des proprits en cisaillement plan (traction f 45O) Luft- und Raumfahrt Faserverstrkte Kunststoffe Prf verf ahren Bestimmung der Schubeigenschaften (* 45O Zugversuch) This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECMA (The European Association of Ae
4、rospace Industries). It is published on green paper for the needs of AECMA-Members. It has been technically approved by the experts of the concerned Technical Committee following comment by the Member countries. Subsequent to the publication of this Prestandard, the technical content shall not be ch
5、anged to an extent that interchangeability 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 d
6、raft European Standard to CEN (European Committee for Standardization) for formal vote. 1995-1 1-30 AECMA Gulledelle 94 B-1200 BRUXELLES Mr K. Schneider I I I aecma 1995 - - AECMA PREN+b03L 95 10l123LL 0009975 584 M Page 2 prEN 6031 : 1995 Contents list 1 2 3 4 5 6 7 8 9 10 Scope Normative reference
7、s Definitions Principle of the method Designation of the method Apparatus Test specimen Procedure Presentation of the results Test report - - - AECMA PREN*b031 95 1012311 0009976 410 Page 3 prEN 6031 : 1995 1 Scope This standard specifies the procedure for the determination of the in-plane shear str
8、ength and modulus of fibre composites. The procedure is based on the uni-axial tensile stress-strain response of a f 45” laminate which is symmetrically laminated about the mid-plane. This standard is applicable to composite laminates manufactured from unidirectional tape or woven fabric reinforceme
9、nt. This standard does not give any directions necessary to meet the health and safety requirements. It is the responsibility of the user of this standard to consult and establish appropriate health and safety precautions. 2 Normative references This European Standard incorporates by dated or undate
10、d reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when in
11、corporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. EN 2374 Aerospace series - Glass fibre reinforced mouldings and sandwich composites - Production of test panels EN 2489 Aerospace series - Fibre reinforced plastics - Determi
12、nation of the action of test fluids” EN 2565 Aerospace series - Preparation of carbon fibre reinforced resin panels for test purposes” EN 2743 Aerospace series - Reinforced plastics - Standard procedures for conditioning prior to testing” EN 2823 Aerospace series - Fibre reinforced plastics - Test m
13、ethod for the determination of the effect of exposure to humid atmosphere on physical and mechanical characteristics 3 Definitions For the purposes of this standard, the following definitions apply: 3.1 Tensile stress at a given moment during the test Longitudinal tensile load experienced by the tes
14、t specimen at a particular moment during the test. divided by the initial unit cross sectional area within the gauge length. 3.2 Shear stress at a given moment during the test The shear stress is defined as the in-plane shear stress with its principal direction under f 45” with the direction in whic
15、h the tension load is applied, and its magnitude is half of the tensile stress. 1) Published as AECMA Prestandard at the date of publication of this standard - - AECMA PREN+b03L 95 W LO12311 0009977 357 W Description block Fibre reinforced plastics, determination of in-plane Page 4 prEN 6031 : 1995
16、Identity block EN 6031 3.3 Shear strength The shear strength is the maximum occuring shear stress during the test. For calculation see 9.1. 3.4 Tensile strain Variation in the longitudinal or transverse distance between points within the test specimen gauge length, produced by a tensile load and exp
17、ressed with respect to the initial distance between the points (eo is the longitudinal strain, its value is positive; is the transverse strain of a tensile specimen, its value is negative). 3.5 Shear modulus Slope of the straight line in a shear stress/strain diagram through the points correspondin
18、with two longitudinal strain limits. Unless otherwise defined these longitudinal strains are (col2 = 2500 x B = 500 x 1 O- and . (see figure 3). For calculation see 9.2. 4 Principle of the method Through the use of relations derived from laminated plate theory, expressions are presented which allow
19、the in-plane Oo shear stress-strain curve to be generated from a uniaxial tension test of a f 45O laminate. Experimental test data from a tensile test are used for generating the shear strength and modulus. 5 Designation of the method The designation of the used method shall be drawn up according to
20、 the following example. 6 Apparatus 6.1 Tensile testing machine, accurate to within 1 %, in the load range used. 6.2 Flat face micrometer accurate to the nearest 0,Ol mm. 6.3 Vernier caliper accurate to the nearest 0,l mm. 6.4 This procedure requires load strain data in both the longitudinal and tra
21、nsverse directions. This is accomplished by instrumenting the specimen with longitudinal and transverse strain gauges (5 to 10 mm gauge length). The gauges, surface preparation, and bonding agents should be chosen to provide for optimal performance on the subject material, and suitable automatic str
22、ain recording equipment shall be employed. If available, a bi-directional extensometer or a combination of longitudinal and a transverse extensometer can be used. The extensometers shall be accurate to within 1 X in the applied load range. AECMA PRENUb031 95 1012311 0009978 293 Page 5 prEN 6031 : 19
23、95 6.5 Temperature measuring equipment accurate to f 0,2OC at the applied test temperature. 6.6 Vacuum bag sealant material. 6.7 Timer/clock. 7 Test specimen 7.1 Test specimen description The test specimen can consist of either unidirectional tape or woven fabric. Eight plies oriented at +45O and -4
24、5O to the longitudinal axis are applied : (+45, -45, +45, -451s. To avoid distortions and induced bending the lay-up shall be fully symmetrical. See figure 1 for dimensions and tolerances of test specimen. 7.2 Test specimen preparation The specimens are cut out of platesThe coefficient of variation
25、in thickness measurements shall be smaller than 2% per plate. The lay-up shall be alternatively at + 45O and -45O and symmetrical (see 7.1). The accuracy of the orientation of the fibers shall be within f 2,5O. Carbon plates shall be produced according to EN 2565, glass plates in accordance with EN
26、2374. The process parameters such as bleeders, curing temperature and time, etc. shall be in accordance with the applicable Technical Specification. All the specimens shall have a f 45O lay-up with respect to the specimen axis. Precautions shall be taken to avoid notches, undercuts, rough or uneven
27、surfaces after machining. 7.3 Strain gauges If strain gauges (see 6.4) are applied for modulus determination, they shall be attached at the centre of the specimen in the longitudinal (Oo) and in the transverse (goo) direction. 7.4 Tabs The specimen shall have tabs (see figure 11, either by using pre
28、cured tabs made by two plies of fabric (lay-up see figure 2 for details. Alignment of the test specimen in the test machine shall be as accurate as possible, in order to avoid introducing any bending loads. The tensile load shall be applied at a crosshead speed of 1 mm/min until 2% longitudinal stra
29、in has been reached; the Oo and 90 strains being recorded versus the load by the strain indicator device (see 6.4) continuously throughout the test. At this point the speed is to be increased to 10 mm/min until failure (if necessary, the strain recording may revert to a longitudinal record of crossh
30、ead movement by constant chart feed only). If strain indicators are used on both sides of the specimen, the strain in each direction is the average of the strain in that direction measured on both sides of the specimen. Note : It is allowed to arrange the longitudinal and transverse strain indicator
31、s in the Wheatstone bridge in such a way that the ia&, - A&go) is measured directly (see 9.2). Record the maximum load carried by the specimen during the test and time to failure. 8.4 Elevated and sub-zero temperature tests Apply a thermocouple (see 6.5) on the composite material as close as possibl
32、e to the centre of the specimen and seal the thermocouple from the surrounding air by using vacuum bag sealant (see 6.6). After a dry specimen has reached a temperature of 2OC below the required elevated temperature or 2OC above the required sub-zero temperature, the specimen shall be maintained at
33、the required condition for 5 minutes prior to testing. The above time for aged specimen is 1 minute. AECMA PREN+b03L 95 1OL23LL 0009980 941 Page 7 prEN 6031 : 1995 9 Presentation of the results 9.1 Shear strength (see 3.3) Pmax wxt 0,5 x - T Where : T is the shear strength, in N/mm2 Pmax is the high
34、est tensile load during testing, in Newton W is the average of the three width measurements per specimen, in millimetres t is the average of the three thickness measurements per specimen, in millimetres 9.2 Shear modulus (see 3.51 AP 0,5 x - G t x mo - A&) Where (see figure 3) : G AP W t Asgo is the
35、 shear modulus, in N/mm2 is the difference in tensile loads at is the average of the three width measurements per specimen, in millimetres is the average of the three thi kness measurements per specimen, in millimetres is the difference in transverse strains corresponding to (note : Acg0 is negative
36、) = 2500 x 1 O-6 and at leo), = 500 x 1 O-6, in Newton 3 aso = - = 2000 x i o = 2500 x 1 O-6 and (Eo) = 500 x 1 O6 Note : If Aco - As, is measured directly (see figure 4) than : AP is the difference in tensile loads at -6 - e9012 = 4500 x and (.z0 - &go)l = 900 x 10 -6 aEo - Acgo = (eo - E) - (eo -
37、= 3600 x io the above strain limits shall be used unless otherwise defined. 10 Test report The test report shall refer to this standard and shall include the following : 10.1 10.2 10.3 10.4 10.5 10.6 Complete identification of the material tested, including at least : material designation, supplier,
38、 batch number, roll number, fibre areal weight, filament count, processing details, stacking sequence, test orientation. All details regarding specimen preparation (including when applicable : tab material, tab adhesive and curing condition of this adhesive). The measured specimen dimensions. Ageing
39、 and/or exposure conditions prior to the test. Date of test, facility and identification of individuals performing the tests. Equipment method and test parameters used. AECMA PRENab03L 95 m 1012311 0009981 888 W Page 8 prEN 6031 : 1995 10.7 A typical set of load-deformation curves (both longitudinal
40、 and transverse). The individual curves shaii be kept in file by the test laboratory. 10.8 Individual values, arithmetic mean and standard deviations per group of specimens of shear strength and shear modulus. 10.9 Any incident which may have affected the results and any deviation from this standard
41、. AECIA PRENUb031 95 LO12311 O009982 714 Page 9 prEN 6031 : 1995 t 8 x cured ply thickness of the used material W - (25,OO e 0,251 mm (730 I 1) mm II L - (230 c 1) rnrn (50 k 1) mm 9 - - - - - O0 =450 : Fibre orientations Main specimen axis in which load is applied Tabs : see 7.4 Parallelism of tab
42、faces must be maintained to within 0,08 rnm across the with Tabs faces must be parallel with specimen faces to within 0,04 mm. * and length. Figure 1 : Test specimen o 7: Grip 2: Tesi soecimen Figure 2 : Position of test specimen in the grips AECMA PRENxb03L 95 D LOL23Ll 0009983 650 Page 10 prEN 6031 : 1995 Figure 3 : P - & curve for the determination of the shear modulus G Figure 4 : P - (&o - E 90) 2 curve for the determination of the shear modulus Go
