1、Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 21/04/2008 03:06, Uncontrolled Copy, (c) BSIg49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58c
2、omposites at room temperature Determination of elastic properties by an ultrasonic techniqueThe European Standard EN 14186:2007 has the status of a British StandardICS 81.060.30Advanced technical ceramics Mechanical properties of ceramic BRITISH STANDARDBS EN 14186:2007BS EN 14186:2007Licensed Copy:
3、 Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 21/04/2008 03:06, Uncontrolled Copy, (c) BSIThis British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2008 BSI 2007ISBN 978 0 580 58326 1Amendments issued since publicationAmd. No. Date Commentscontra
4、ct. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.National forewordThis British Standard is the UK implementation of EN 14186:2007. It supersedes DD ENV 14186:2002 which is withdrawn.The UK participation in its prep
5、aration was entrusted to Technical Committee RPI/13, Advanced technical ceramics.A list of organizations 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 EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE
6、 NORMEN 14186November 2007ICS 81.060.30 Supersedes ENV 14186:2002 English VersionAdvanced technical ceramics - Mechanical properties of ceramiccomposites at room temperature - Determination of elasticproperties by an ultrasonic techniqueCramiques techniques avances - Proprits mcaniquesdes cramiques
7、composites temprature ambiante -Dtermination des proprits lastiques par une mthodeultrasonoreHochleistungskeramik - Mechanische Eigenschaftenkeramischer Verbundwerkstoffe bei Raumtemperatur -Bestimmung von elastischen Eigenschaften mittelsUltraschallwellenThis European Standard was approved by CEN o
8、n 13 October 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may
9、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 language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN M
10、anagement Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, No
11、rway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form a
12、nd by any means reservedworldwide for CEN national Members.Ref. No. EN 14186:2007: ELicensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 21/04/2008 03:06, Uncontrolled Copy, (c) BSIEN 14186:2007 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Principle
13、7 5 Significance and use .10 6 Apparatus .10 6.1 Ultrasonic tank with thermostatic control.10 6.2 Temperature measurement device 10 6.3 Test specimen holder10 6.4 Transducers .11 6.5 Transducer holders .11 6.6 Pulse generator11 6.7 Signal recording system .11 7 Test specimens11 8 Test specimen prepa
14、ration.11 9 Test procedure.12 9.1 Choice of frequency 12 9.2 Establishment of the test temperature 12 9.3 Reference test without test specimen .12 9.4 Measurement with the specimen .13 10 Calculation14 10.1 Delay .14 10.2 Calculation of the propagation velocities .14 10.3 Calculation of the refracte
15、d angle r.14 10.4 Identification of the elastic constants, Cij.14 10.5 Back calculation of the phase velocities.18 10.6 Polar plots of the velocity curves 18 10.7 Calculation of the quadratic deviation.18 10.8 Calculation of the engineering constants .18 11 Test validity 19 11.1 Measurements19 11.2
16、Criterion of validity for the reliability of the Cijcomponents19 12 Test report 19 Annex A (informative) Example of a presentation of the results for a material with orthothropic symmetry 21 A.1 Velocity curves.21 A.2 Stiffness matrix with stiffness components .22 A.3 Engineering constants 23 Biblio
17、graphy 24 Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 21/04/2008 03:06, Uncontrolled Copy, (c) BSIEN 14186:2007 (E) 3 Foreword This document (EN 14186:2007) has been prepared by Technical Committee CEN/TC 184 “Advanced technical ceramics”, the secretariat of which is held by BSI. This Eur
18、opean Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2008, and conflicting national standards shall be withdrawn at the latest by May 2008. This document supersedes ENV 14186:2002. According to the CEN/CEN
19、ELEC 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, Latvia, Lithuania, Luxem
20、bourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 21/04/2008 03:06, Uncontrolled Copy, (c) BSIEN 14186:2007 (E) 4 1 Scope This European Standard specifies an ultrason
21、ic method to determine the components of the elasticity tensor of ceramic matrix composite materials at room temperature. Youngs moduli, shear moduli and Poisson coefficients, can be determined from the components of the elasticity tensor. This European Standard applies to ceramic matrix composites
22、with a continuous fibre reinforcement: unidirectional (1D), bidirectional (2D), and tridirectional (D, with 2 3) which have at least orthotropic symmetry, and whose material symmetry axes are known. This method is applicable only when the ultrasonic wave length used is larger than the thickness of t
23、he representative elementary volume, thus imposing an upper limit to the frequency range of the transducers used. NOTE Properties obtained by this method might not be comparable with moduli obtained by EN 658-1, EN 658-2 and EN 12289. 2 Normative references The following referenced documents are ind
24、ispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1389, Advanced technical ceramics Ceramic composites Physical properties Determination o
25、f density and apparent porosity CEN/TR 13233:2007, Advanced technical ceramics Notations and symbols EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:2005) ISO 3611, Micrometer callipers for external measurements 3 Terms and definitions
26、 For the purposes of this document, the terms and definitions given in CEN/TR 13233:2007 and the following apply. 3.1 stress-strain relations for orthotropic material elastic anisotropic behaviour of a solid homogeneous body described by the elasticity tensor of fourth order Cijkl, represented in th
27、e contracted notation by a symmetrical square matrix (6 6) NOTE 1 If the material has at least orthotropic symmetry, its elastic behaviour is fully characterised by nine independent stiffness components Cij, of the stiffness matrix (Cij), which relates stresses to strains, or equivalently by nine in
28、dependent compliance components Sijof the compliance matrix (Sij), which relates strains to stresses. The stiffness and compliance matrices are the inverse of each other. If the reference coordinate system is chosen along the axes of symmetry, the stiffness matrix Cijand the compliance matrix Sijcan
29、 be written as follows: Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 21/04/2008 03:06, Uncontrolled Copy, (c) BSIEN 14186:2007 (E) 5 =654321665544332313232212131211654321000000000000000000000000CCCCCCCCCCCC=654321665544332313232212131211654321000000000000000000000000SSSSSSSSSSSSNOTE 2 For
30、symmetries of higher level than the orthotropic symmetry, the Cijand Sijmatrices have the same form as here above. Only the number of independent components reduces. 3.2 engineering constants compliance matrix components of an orthotropic material which are in terms of engineering constants: =121333
31、2223111333322211123331222111100000001000000100010001GGEEvEvEvEEvEvEvESijwhere E11, E22and E33are the elastic moduli in directions 1, 2 and 3 respectively; G12, G13and G23are the shear moduli in the corresponding planes; 12, 13, 23are the respective Poisson coefficients 3.3 angle of incidence iangle
32、between the direction 3 normal to the test specimen front face and the direction niof the incident wave (see Figure 1 and Figure 2) Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 21/04/2008 03:06, Uncontrolled Copy, (c) BSIEN 14186:2007 (E) 6 3.4 refracted angle iangle between the direction
33、3 normal to the test specimen front face and the direction n of propagation of the wave inside the test specimen (see Figure 1 and Figure 2) 3.5 azimuthal angle angle between the plane of incidence (3, ni) and plane (2, 3) where nicorresponds to the vector oriented along the incident plane wave and
34、direction 2 corresponds to one of the axes of symmetry of the material (see Figure 1) Figure 1 Definition of the angles Figure 2 Propagation in the plane of incidence Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 21/04/2008 03:06, Uncontrolled Copy, (c) BSIEN 14186:2007 (E) 7 3.6 unit vecto
35、r n unit vector oriented along the propagation direction of the incident plane wave inside the specimen, with its components nk(k = 1, 2, 3) (see Figure 1 and Figure 2): n1= sinrsin n2= sinrcos n3= cosr3.7 propagation velocity V(n) phase velocity of a plane wave inside the specimen in dependence on
36、unit vector n (i.e. in dependence on and i) NOTE Vois the propagation velocity in the coupling fluid. 3.8 delay t(n) difference between the flight time of the wave when the test specimen is in place and the flight time of the wave in the coupling fluid with the test specimen removed under the same c
37、onfiguration of the transducers in dependence on unit vector n 3.9 thickness of the test specimen h thickness of the test specimen 3.10 bulk density bbulk density of the specimen 4 Principle The determination of the elastic properties consists of calculating the coefficients of the propagation equat
38、ion of an elastic plane wave, from a set of properly chosen velocity measurements along known directions. A thin specimen with plane parallel faces is immersed in an acoustically coupling fluid (e.g. water): see Figure 3. The specimen is placed between an emitter (E) and a receiver (R), which are ri
39、gidly connected to each other and have two rotational degrees of freedom. Using appropriate signal processing, the propagation velocities of each wave in the specimen are calculated. Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 21/04/2008 03:06, Uncontrolled Copy, (c) BSIEN 14186:2007 (E)
40、8 Key 1 rotation drive 2 test specimen 3 pulse generator 4 digital oscilloscope 5 micro-computer Figure 3 Ultrasonic test assembly Depending on the angle of incidence, the pulse sent by the emitter E is refracted within the material in one, two or three bulk waves (one quasi longitudinal wave QL, on
41、e quasi transverse wave QT, or two quasi transverse waves QT1, QT2) that propagate in the solid at different velocities and in different directions. The receiver R collects one, two or three pulses, corresponding to each of these waves. The difference in propagation time of each of the waves and the
42、 propagation time of the emitted pulse in the coupling fluid without the specimen is measured. The evaluation procedure is based on the measurement of the time difference of the quasi-longitudinal and one or both quasi-transverse waves, and is only valid when the QL and the QT waves are appropriatel
43、y separated (see Figure 4). Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 21/04/2008 03:06, Uncontrolled Copy, (c) BSIEN 14186:2007 (E) 9 Key 1 amplitude 2 incidence angle Figure 4a) Amplitude of the QL and QT waves as a function of the incidence angle Key 1 amplitude 2 time Figure 4b) Temp
44、oral waveform of the overlapping QL and QT waves at an incidence angle iFigure 4 Overlapping of QL and QT waves at an incidence angle iFrom the propagation velocities the components of the elasticity tensor are obtained through a least square regression analysis which minimises the residuals of the
45、wave propagation equations. Youngs moduli, shear moduli and Poisson coefficients are determined from these components. Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 21/04/2008 03:06, Uncontrolled Copy, (c) BSIEN 14186:2007 (E) 10 5 Significance and use Only two constants (Lams coefficients
46、or Youngs modulus and Poisson coefficient) are sufficient in order to fully describe the elastic behaviour of an isotropic body. When anisotropy, which is a specific feature of composite materials, shall be taken into account, the use of an elasticity tensor with a larger number of independent coeff
47、icients is needed. While conventional mechanical methods allow only a partial identification of the elasticity of anisotropic bodies, ultrasonic techniques allow a more exhaustive evaluation of the elastic properties of these materials particularly transverse elastic moduli and shear moduli for thin
48、 specimens. Successful application of the method depends critically on an appropriate selection of the central frequency of the transducers. Frequency shall be sufficiently low for the measurement to be representative of the elementary volume response, but at the same time high enough to achieve a s
49、eparation between the QL and the QT waves. Contrary to mechanical test methods, the determination of elastic properties by the ultrasonic method described here 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-destructiv
