1、BRITISH STANDARDBS EN 15335:2007Advanced technical ceramics Ceramic composites Determination of elastic properties by resonant beam method up to 2 000 CThe European Standard EN 15335:2007 has the status of a British StandardICS 81.060.30g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44
2、g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Licensed Copy: Wang Bin, na, Tue Oct 16 01:44:50 GMT+00:00 2007, Uncontrolled Copy, (c) BSIBS EN 15335:2007This British Standard was published under the authority
3、of the Standards Policy and Strategy Committee on 31 July 2007 BSI 2007ISBN 978 0 580 55779 8National forewordThis British Standard is the UK implementation of EN 15335:2007. The UK participation in its preparation was entrusted to Technical Committee RPI/13, Advanced technical ceramics.A list of or
4、ganizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obliga
5、tions.Amendments issued since publicationAmd. No. Date CommentsLicensed Copy: Wang Bin, na, Tue Oct 16 01:44:50 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 15335 May 2007 ICS 81.060.30 English Version Advanced technical ceramics - Ceramic composites
6、 - Determination of elastic properties by resonant beam method up to 2 000 C Cramiques techniques avances - Cramiques composites - Dtermination des proprits lastiques par une mthode de rsonance sur poutres, jusqu 2 000 C Hochleistungskeramik - Keramische Verbundwerkstoffe - Bestimmung der elastische
7、n Eigenschaften bei Verwendung des Resonanz-Verfahrens bis 2 000 C This European Standard was approved by CEN on 26 April 2007. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard
8、 without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other lan
9、guage made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finl
10、and, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES K
11、OMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 15335:2007: ELicensed Copy: Wang Bin, na, Tue Oct 16 01:44:50 GMT+00:00 2007, Uncontrolled Copy, (c) BSIE
12、N 15335:2007 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Principle5 5 Significance and use .5 6 Apparatus .6 6.1 Vacuum vessel.6 6.2 Transducers .7 6.3 Carbon fibre-bundle loops7 6.4 Pumping unit7 6.5 Control and evaluation units 7 6.6 Balance .7 6.7
13、 Micrometer8 6.8 Callipers8 7 Test specimens8 7.1 General8 7.2 Shape and dimensions9 7.3 Plane parallelism9 7.4 Number of test specimens9 8 Test procedure.9 8.1 Test specimen preparation.9 8.2 Adjustment of the apparatus9 8.3 Measurement at room temperature10 8.4 Measurement at high temperatures.10
14、9 Calculation of results 11 9.1 Basic concept.11 9.2 How to calculate eigenfrequencies11 9.3 Identification, matching and fitting16 9.4 The two evaluation steps 18 10 Accuracy of method and errors .19 11 Test report 20 Annex A (informative) Example .21 A.1 General21 A.2 Measurement23 A.3 First evalu
15、ation step24 A.4 Second evaluation step.26 A.5 Results 26 Bibliography 28 Licensed Copy: Wang Bin, na, Tue Oct 16 01:44:50 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 15335:2007 (E) 3 Foreword This document (EN 15335:2007) has been prepared by Technical Committee CEN/TC 184 “Advanced technical cera
16、mics”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2007, and conflicting national standards shall be withdrawn at the latest by November 2007.
17、 According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
18、 Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: Wang Bin, na, Tue Oct 16 01:44:50 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 15335:2007 (E) 4 1 Scope This European Standard spec
19、ifies the resonant beam method for the determination of the dynamic elastic moduli of fibre reinforced ceramic matrix composites from 20 C up to 2 000 C in vacuum or inert atmosphere. The Youngs moduli and the shear moduli for different orientations with respect to the main axes of symmetry of the c
20、omposite can be obtained. This document applies to ceramic matrix composites with fibre reinforcement: short fibres, unidirectional (1D), bidirectional (2D), and tridirectional (xD, with 2 x 3) which have at least orthothropic symmetry. NOTE 1 Dynamic means that the elastic moduli are determined non
21、-quasistatically, i.e. under adiabatic conditions, as with the ultrasonic method set out in ENV 14186. The elastic moduli determined by this method may not be compared with moduli obtained in an isothermal condition by stressing statically or quasistatically as with EN 658-1, EN 658-2, EN 1892, EN 1
22、893, EN 12290 and EN 12291. NOTE 2 The ceramic matrix composites with fibre reinforcement, listed above, are denoted as “composites” in the course of the document. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references,
23、only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 60584-1, Thermocouples Part 1: Reference tables (IEC 60584-1:1995) EN 60584-2, Thermocouples Part 2: Tolerances (IEC 60584- 2:1982 + A1:1989) EN ISO/IEC 17025,
24、 General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:2005) ISO 3599, Vernier callipers reading to 0,1 and 0,05 mm ISO 3611, Micrometer callipers for external measurement 3 Terms and definitions For the purposes of this document, the following terms and defi
25、nitions apply. 3.1 Youngs modulus, E stress required in a material to produce unit strain in uniaxial extension or compression 3.2 shear modulus, G shear stress required in a material to produce unit angular distortion 3.3 Poissons ratio, ratio of transverse strain to the corresponding axial strain
26、NOTE E11, E22and E33are the elastic moduli in directions 1, 2 and 3 respectively, G12, G13and G23are the shear moduli in the corresponding planes and 12, 13, 23are the respective Poisson ratios. Licensed Copy: Wang Bin, na, Tue Oct 16 01:44:50 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 15335:2007
27、(E) 5 4 Principle The test specimen, a long thin prismatic beam (ratio of length to width or length to height bigger than 10), cut from the composite along a specific orientation of interest, is excited to bending vibrations. The mechanical excitation at continuously variable frequencies is provided
28、 by means of a transducer that transforms cyclic electrical signals to cyclic mechanical forces on the test specimen. A second transducer senses the resulting mechanical vibrations of the test specimen and transforms them into electrical signals. The resulting spectrum (amplitude as function of freq
29、uency) up to frequencies enclosing the sixth mode of vibrations of the test specimen, is registered and stored in a spectrum analyser. From the resonant frequencies, i.e. the peaks of the spectrum (fundamental vibration and harmonics up to the sixth mode), the dimensions and the density of the test
30、specimen, the elastic moduli can be calculated by numerically solving Timoshenkos equation. For one test specimen the Youngs modulus and two shear moduli in directions perpendicular to each other can be achieved. NOTE When anisotropy, a specific feature of composites, is taken into account, the elas
31、tic behaviour can be fully characterised only by the elasticity tensor with a certain number of independent coefficients, this number depending on the crystallographic symmetry of the composite (a method to determine the elasticity tensor for composites is given in ENV 14186). From these coefficient
32、s the elastic moduli (Youngs moduli, shear moduli and Poisson ratios) can be calculated. 5 Significance and use The resonant beam method is frequently applied for the determination of the dynamic elastic moduli in standardisation for example: EN 843-2, CEN/TS 820-5, ISO 17561, ASTM C848-88, ASTM C62
33、3-92(2005). For all these applications, it is common that the influence of shear, which is the bigger, the higher and the mode of vibration, is ruled out. For the calculation of results a formula basing on the Euler-Bernoulli relation, valid for the fundamental mode only, is applied and is combined
34、with correction factors for higher modes (in general only the first mode, i.e. the first overtone is considered additionally to the fundamental mode). The shear moduli are determined separately from torsional vibrations. The method specified in this document turns the problem around. The higher mode
35、s are taken into account (up to the sixth mode) and thus shear deformation is provoked for the determination of the shear moduli with bending vibrations. In this document an equation, derived from Timoshenkos equation, taking into account for shear, is applied for the calculation of the moduli. With
36、 the resonant beam method specified in this document, the elastic moduli are determined in principle for one test specimen. One Youngs modulus and two shear moduli are determined in directions perpendicular to each other. The Youngs modulus is the longitudinal modulus in the length direction of the
37、prismatic test specimen, while the shear moduli are the moduli along the width and thickness of the test specimen (Poisson ratios can be calculated from these moduli). Thus it is important to observe in which direction, with respect to the crystallographic symmetry, the prismatic test specimen is cu
38、t from the composite. For example, from a 2,5 D- or a 3 D-composite (orthothropic symmetry) test specimens can be cut out perpendicular to each other in reinforcing directions 1, 2 and 3, so that the Youngs moduli E11, E22, E33and the shear moduli G12, G23, G13can be determined. For a plate of a 2D-
39、composite (quadratic or tetragonal symmetry), with a test specimen cut out in the direction of the fibre reinforcement, direction 1, the technique specified in this document generates the longitudinal modulus E11, the interlaminar shear modulus G13and the intralaminar shear modulus G12. Additionally
40、 for such a plate the modulus E22could be determined from a specimen cut out in direction 2, but neither E33in the direction of the thickness of the plate, nor the shear modulus G23. Contrary to mechanical test methods, the determination of elastic properties by the resonant beam method specified he
41、re is not based on the evaluation of the stress-strain response over a given deformation range obtained under quasi static loading conditions, but is based on a non-destructive dynamic measurement from vibrations at very small amplitudes. Therefore the values of Youngs modulus, shear modulus and Poi
42、sson Licensed Copy: Wang Bin, na, Tue Oct 16 01:44:50 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 15335:2007 (E) 6 ratio determined by the two types of methods just mentioned may not be comparable, particularly for ceramic matrix composites, which may exhibit non linear stress-strain behaviour. 6 A
43、pparatus 6.1 Vacuum vessel Inside a vacuum chamber the prismatic test specimen is suspended by loops of carbon fibre bundles (a few hundred fibres each) and excited to bending vibrations via one of these loops. The test specimen hangs into a heating element (optionally this should be partly removabl
44、e when adjusting the test specimen at room temperature). The characteristic spectrum of bending vibrations is registered via the other loop at the temperatures of interest. See an example of a vacuum vessel illustrated in Figure 1. Key a control and evaluation unit h transducer in a water-cooled hou
45、sing: the Transmitter b network analyser i transducer in a water-cooled housing: the Receiver c temperature control j insulating felt d pyrometer k prismatic test specimen e thermocouple l heating element f vacuum vessel m carbon fibre loops g pumping unit NOTE The prismatic test specimen is excited
46、 to bending vibrations and the frequency spectrum is transmitted by carbon fibre-bundle loops attached to transducers in water-cooled housings (right), 1, 2. Figure 1 Schematic of the resonant beam method apparatus Licensed Copy: Wang Bin, na, Tue Oct 16 01:44:50 GMT+00:00 2007, Uncontrolled Copy, (
47、c) BSIEN 15335:2007 (E) 7 6.2 Transducers The transducers shall introduce sinusoidal vibrations of a certain range of frequencies (generated by a frequency synthesiser) to one end of the test specimen and collect the resonant spectrum of the test specimen on the other end. The transducers shall have
48、 a flat response curve (i.e. no resonances of its own). Both, sinusoidal vibrations and flat response are necessary to perform the method. Piezo-ceramics (piezoelectric effect), with a range of operation 1 kHz to 200 kHz and a signal to noise ratio 20 dB, should be used. 6.3 Carbon fibre-bundle loop
49、s Loops of carbon fibre-bundles with a few hundred fibres in the bundle to transmit and receive introduce and accept the spectrum of vibrations. The ends of each of the bundles are fixed by a polymeric glue into a short tube (the tube should be made of aluminium, outer diameter 3, inner diameter 1,5 mm, ending in a metric thread, M 2,5 should be used). The tubes with the glued in bundles are screwed into a cylindrical foot, which is directly glued to the transducers (piezo-ceramics). The transducers are enclosed in water cooled housi
