BS EN 15158-2006 Advanced technical ceramics - Mechanical properties of ceramic composites at high temperature under inert atmosphere - Determination of fatigue properties at const.pdf

1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58composites at high temperature under inert atmosphere Determination of fatigue properties at consta

2、nt amplitudeThe European Standard EN 15158:2006 has the status of a British StandardICS 81.060.30Advanced technical ceramics Mechanical properties of ceramic BRITISH STANDARDBS EN 15158:2006BS EN 15158:2006This British Standard was published under the authority of the Standards Policy and Strategy C

3、ommittee on 29 September 2006 BSI 2006ISBN 0 580 49054 8 Amendments issued since publicationAmd. No. Date Commentscontract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.National forewordThis British Standard was pu

4、blished by BSI. It is the UK implementation of EN 15158:2006.The UK participation in its preparation was entrusted to Technical Committee RPI/13, Advanced technical ceramics. A list of organizations represented on RPI/13 can be obtained on request to its secretary.This publication does not purport t

5、o include all the necessary provisions of a EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 15158August 2006ICS 81.060.30English VersionAdvanced technical ceramics - Mechanical properties of ceramiccomposites at high temperature under inert atmosphere -Determination of fatigue properties at consta

6、nt amplitudeCramiques techniques avances - Proprits mcaniquesdes cramiques composites haute temprature sousatmosphre inerte - Dtermination des proprits defatigue amplitude constanteHochleistungskeramik - Mechanische Eigenschaften vonkeramischen Verbundwerkstoffen bei hoher Temperatur ininerter Atmos

7、phre - Bestimmung derDauerschwingeigenschaften bei Belastung mit konstanterAmplitudeThis European Standard was approved by CEN on 14 July 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a nat

8、ional standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any

9、 other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland,

10、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 STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR

11、NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15158:2006: EEN 15158:2006 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Terms, definitions and s

12、ymbols.5 4 Principle8 5 Significance and use .8 6 Apparatus .9 6.1 Fatigue test machine .9 6.2 Load train9 6.3 Test chamber10 6.4 Set-up for heating 10 6.5 Extensometer .10 6.6 Temperature measurement.11 6.7 Data recording system 11 6.8 Micrometers11 7 Test specimens11 8 Test specimen preparation.12

13、 8.1 Machining and preparation.12 8.2 Number of test specimens12 9 Test procedure.12 9.1 Test set-up: temperature considerations12 9.2 Measurement of test specimen dimensions .13 9.3 Testing technique 13 9.4 Test validity 14 10 Calculation of results 15 10.1 Time to failure, tf15 10.2 Damage paramet

14、ers 15 10.3 Residual properties .17 11 Test report 17 Annex A (informative) Schematic evolution of E .18 EN 15158:2006 (E) 3 Foreword This document (EN 15158:2006) has been prepared by Technical Committee CEN/TC 184 “Advanced technical ceramics”, the secretariat of which is held by BSI. This Europea

15、n Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February 2007, and conflicting national standards shall be withdrawn at the latest by February 2007. According to the CEN/CENELEC Internal Regulations, the nati

16、onal standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Po

17、rtugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 15158:2006 (E) 4 1 Scope This European Standard specifies the conditions for the determination of constant-amplitude of load or strain in uniaxial tension/tension or in uniaxial tension/compression cyclic fatigue

18、properties of ceramic matrix composite materials (CMCs) with fibre reinforcement for temperature up to 2 000 C under vacuum or a gas atmosphere which is inert to the material under test. NOTE Test environments are specified which are intended to prevent the material under test from chemically reacti

19、ng with them. This European Standard applies to all ceramic matrix composites with fibre reinforcement, unidirectional (1D), bi-directional (2D), and tri-directional (xD, where 2 150 0,5 l, calibrated length 30 to 80 0,5 h, thickness 2 0,2 b1, width in the calibrated length 8 to 20 0,2 b2, width B2=

20、 b1with = 1,2 to 2 0,2 r, radius 30 2 Parallelism of machined parts 0,05 - 8 Test specimen preparation 8.1 Machining and preparation During cutting out, care shall be taken to align the test specimen axis with the desired fibre related loading axis. Machining parameters which avoid damage to the mat

21、erial shall be established and documented. These parameters shall be adhered to during test specimen preparation. 8.2 Number of test specimens At least three valid test results, as specified in 9.4 are required for any condition. 9 Test procedure 9.1 Test set-up: temperature considerations 9.1.1 Gen

22、eral The following determinations shall be carried out under conditions representative of the tests, and shall be repeated every time there is a change in material, in specimen geometry, in gripping configuration etc. In establishing them, time shall be allowed for temperature stabilization. 9.1.2 C

23、ontrolled temperature zone Prior to testing, the temperature gradient within the calibrated length inside the furnace shall be established over the temperature range of interest. This shall be done by measuring the specimen temperature at a minimum of three locations, which shall be the two extensom

24、eter reference points and a point midway between the two. To establish the length of the controlled temperature zone, it is necessary to measure the temperature also outside the gauge length. The temperature variation within the controlled temperature zone and the gauge length shall meet the require

25、ments of Clause 7 and 6.4, respectively. EN 15158:2006 (E) 13 Temperatures may be measured by any means conforming to 6.6. If thermocouples are used to measure the temperature at different locations of the specimen, they shall be embedded (and sealed if necessary) into the specimen to a depth approx

26、imately equal to half the specimen dimension in the direction of insertion. 9.1.3 Temperature calibration During a series of tests, the test temperature can be determined either directly by measurement on the specimen itself, or indirectly from the temperature indicated by the temperature control de

27、vice. In the latter case, the relationship between the control temperature and test specimen temperature at the centre of the gauge length shall be established beforehand on a dummy test specimen over the range of temperature of interest. NOTE The relationship between the temperature indicated by th

28、e temperature control system and the test temperature is usually established simultaneously with the controlled temperature zone. 9.2 Measurement of test specimen dimensions The cross-section area shall be determined at the centre of the specimen and at each end of the gauge length. The cross-sectio

29、n area varies with temperature and the variation is very difficult to measure. For this reason, the cross-section area shall be measured at room temperature. Dimensions shall be measured to an accuracy of 0,01 mm. The arithmetic means of the measurements shall be used for calculations. 9.3 Testing t

30、echnique 9.3.1 Specimen mounting Install the test specimen in the gripping system with its longitudinal axis coinciding with that of the test machine. Care shall be taken not to induce flexural or torsional loads in the test specimen. 9.3.2 Setting the extensometer In the case where a contacting ext

31、ensometer is positioned at ambient temperature, the extensometer output shall be adjusted to read zero after the stabilization period at the test temperature. NOTE In the case where the material has a high thermal expansion coefficient, it is recommended to mechanically pre-set the extensometer taki

32、ng expansion into account in order to be close to zero when at test temperature. 9.3.3 Establishing the inert atmosphere When testing under inert gas, any air or water vapour shall be removed before setting the inert atmosphere. This can be done by establishing vacuum (below 10 MPa) in the enclosure

33、, or by circulating inert gas. When testing under vacuum, the vacuum level shall be in accordance with 6.3. 9.3.4 Heating the test specimen Raise the test specimen temperature to the required test temperature, and maintain this temperature for a period to allow for temperature stabilization and if a

34、pplicable, for stabilization of the extensometer readout. Two procedures are possible: if test specimen temperature is measured during the test on the specimen itself, this temperature shall be used to control the furnace. If it is not possible to measure directly the test specimen temperature durin

35、g the test, then it is necessary to use the relation between test specimen temperature and EN 15158:2006 (E) 14 furnace temperature which has been established in 9.1. Ensure that the test specimen stays in the initial state of stress during heating. 9.3.5 Measurements zero the load cell; zero the ex

36、tensometer, if applicable; set the maximum number of cycles, N; for method A, set the maximum and minimum stress values; for method B, set the maximum and minimum strain values; set the frequency and the wave shape; start the fatigue test: for method A, in load control mode; for method B, in strain

37、control mode; record the number of cycles N or Nf; if an extensometer is used, record the stress-strain loops up to the total number of cycles. NOTE A specific computer program is recommended to control the test. Depending on the computerized facilities used, all the loops can be recorded. If this i

38、s not possible, the following sequence can be used to record stress versus strain: every cycle for the first 10 cycles; one cycle every 10 cycles between 10 and 100 cycles; one cycle every 100 cycles between 100 and 1 000 cycles; one cycle every 1 000 cycles between 1 000 and 10 000 cycles; etc. 9.4

39、 Test validity The following circumstances shall invalidate a test for the determination of the lifetime duration: failure to specify and record test conditions; specimen slippage in the grips; rupture in an area outside of the controlled temperature zone. In addition, the following circumstances sh

40、all invalidate a test for the determination of the damage parameter: extensometer slippage; extensometer drift. EN 15158:2006 (E) 15 10 Calculation of results 10.1 Time to failure, tfCalculate the time to failure in accordance with the following equation: tf(hours) = Nf/ (f x 3 600) where Nfis the n

41、umber of cycles required to obtain failure of the test specimen; f is the frequency, in hertz (Hz). 10.2 Damage parameters Calculate the damage parameter Dnfor each recorded cycle, n, in accordance with the following equation: app1,appn,nEED =1 where Dnis the damage parameter at the nthfatigue cycle

42、; En,appis the secant modulus of the nthfatigue loop (see Figure 4); E1,appis the secant modulus of the first fatigue loop (see Figure 4); Enappis equal to: (max)/(max nresidual) (see Figure 4). nresidual is equal to: (unl+l)/2 (see Figure 4 b). EN 15158:2006 (E) 16 a) R = 0 b) R 0 Key 1 strain () 2

43、 stress () 3 cycle 1 4 cycle n lloading unlunloading Figure 4 Fatigue stress-strain curves with a) R = 0, b) R 0 EN 15158:2006 (E) 17 The damage parameters, Dn, max,residcan be plotted versus the number of cycles, N. For N, a log scale is almost always used, although a linear scale may also be used.

44、 Figures 4a) to 4c) represent three cases of cyclic fatigue of CMCs. NOTE Annex A shows the schematic evolution of E under different circumstances of damage and creep. 10.3 Residual properties When rupture does not occur before the end of the test, test specimen shall be tested to rupture in accorda

45、nce with EN 1892, EN 1893 or EN 658-1. 11 Test report The test report shall contain the following information: a) name and address of the testing establishment; b) date of the test, unique identification of report and of each page, customers name, address and signature; c) a reference to this Europe

46、an Standard, i.e. EN 15158; d) test specimen drawing or reference; e) description of the test material (material type, manufacturing code, batch number); f) description of the test set up : extensometer, gripping system, load cell; g) frequency in hertz; h) wave form; i) maximum and minimum stress (

47、method A); j) maximum and minimum strain (method B); k) number of cycles to failure; if test is stopped at a specified number of cycles without failure occurring it shall be so registered; l) residual properties (if applicable); m) number of tests carried out and number of valid results obtained; n)

48、 damage parameter, if applicable; o) failure location of all the specimens used for obtaining the above results, if applicable. EN 15158:2006 (E) 18 Annex A (informative) Schematic evolution of E Figure A.1 shows a schematic evolution of E where there is a) no damage, b) creep but no fatigue damage

49、and c) fatigue damage and eventual creep. a) No damage b) No fatigue damage only creep c) Fatigue damage plus eventual creep Key 1 first cycle 2 last cycle Figure A.1 Schematic evolution of E with a) no damage, b) creep but no fatigue damage and c) fatigue damage and eventual creep blankBS EN BSI389 Chiswick High RoadLondonW4 4AL15158:2006BSI British Standards InstitutionBSI is the independent national body responsible for preparing British