BS EN 15157-2006 Advanced technical ceramics - Mechanical properties of ceramic composites at high temperature in air at atmospheric pressure - Determination of fatigue properties .pdf

1、BRITISH STANDARDBS EN 15157:2006Advanced technical ceramics Mechanical properties of ceramic composites at high temperature in air at atmospheric pressure Determination of fatigue properties at constant amplitudeThe European Standard EN 15157:2006 has the status of a British StandardICS 81.060.30g49

2、g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Licensed Copy: Wang Bin, na, Thu Dec 14 05:53:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSIBS EN 15157:

3、2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 September 2006 BSI 2006ISBN 0 580 49053 XNational forewordThis British Standard was published by BSI. It is the UK implementation of EN 15157:2006.The UK participation in its preparation

4、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 to include all the necessary provisions of a contract. Users are responsible for its correct applicatio

5、n.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsLicensed Copy: Wang Bin, na, Thu Dec 14 05:53:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSIEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 15157August 2006ICS

6、 81.060.30English VersionAdvanced technical ceramics - Mechanical properties of ceramiccomposites at high temperature in air at atmospheric pressure -Determination of fatigue properties at constant amplitudeCramiques techniques avances - Proprits mcaniquesdes cramiques composites haute temprature da

7、ns lair pression atmosphrique - Dtermination des propritsde fatigue amplitude constanteHochleistungskeramik - Mechanische Eigenschaften vonkeramischen Verbundwerkstoffen bei hoher Temperatur inLuft bei Atmosphrendruck - Bestimmung derDauerschwingeigenschaften bei Belastung mit konstanterAmplitudeThi

8、s 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 national standard without any alteration. Up-to-date lists and bibliographical references

9、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 other language made by translationunder the responsibility of a CEN member into its ow

10、n 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, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg

11、, Malta, Netherlands, Norway, 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 2006 CEN All rights of ex

12、ploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15157:2006: ELicensed Copy: Wang Bin, na, Thu Dec 14 05:53:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSIEN 15157:2006 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Terms, definitions a

13、nd symbols.5 4 Principle8 5 Significance and use .8 6 Apparatus .9 6.1 Fatigue test machine .9 6.2 Load train9 6.3 Set-up for heating 10 6.4 Extensometer .10 6.5 Temperature measurement.10 6.6 Data recording system 10 6.7 Micrometers10 7 Test specimens11 8 Test specimen preparation.12 8.1 Machining

14、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 14 10.1 Time to failure, tf14 10.2 Damage parameters 15 10.3 Res

15、idual properties .15 11 Test report 17 Annex A (informative) Schematic evolution of E .18 Licensed Copy: Wang Bin, na, Thu Dec 14 05:53:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSIEN 15157:2006 (E) 3 Foreword This document (EN 15157:2006) has been prepared by Technical Committee CEN/TC 184 “Advance

16、d technical ceramics”, 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 February 2007, and conflicting national standards shall be withdrawn at the latest b

17、y February 2007. According to the CEN/CENELEC Internal Regulations, the national 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,

18、Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: Wang Bin, na, Thu Dec 14 05:53:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSIEN 15157:2006 (E) 4 1 Scope This European Standar

19、d specifies the conditions for the determination of constant-amplitude of load or strain in uniaxial tension/tension or in uniaxial tension/compression cyclic fatigue properties of ceramic matrix composite materials (CMCs) with fibre reinforcement for temperature up to 1 700 C in air at atmospheric

20、pressure. 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= b1w

21、ith = 1,2 to 2 0,2 r, radius 30 2 Parallelism of machined parts 0,05 - Licensed Copy: Wang Bin, na, Thu Dec 14 05:53:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSIEN 15157:2006 (E) 12 8 Test specimen preparation 8.1 Machining and preparation During cutting out, care shall be taken to align the test s

22、pecimen axis with the desired fibre related loading axis. Machining parameters which avoid damage to the material 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 i

23、n 9.4 are required for any condition. 9 Test procedure 9.1 Test set-up: temperature considerations 9.1.1 General 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 gr

24、ipping configuration etc. In establishing them, time shall be allowed for temperature stabilization. 9.1.2 Controlled 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

25、 done by measuring the specimen temperature at a minimum of three locations, which shall be the two extensometer 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.

26、The temperature variation within the controlled temperature zone and the gauge length shall meet the requirements of Clause 7 and 6.3 respectively. Temperatures may be measured by any means conforming to 6.5. If thermocouples are used to measure the temperature at different locations of the specimen

27、, they shall be embedded (and sealed if necessary) into the specimen to a depth approximately 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 speci

28、men itself, or indirectly from the temperature indicated by the temperature control device. 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

29、temperature of interest. NOTE The relationship between the temperature indicated by the temperature control system and the test temperature is usually established simultaneously with the controlled temperature zone. Licensed Copy: Wang Bin, na, Thu Dec 14 05:53:13 GMT+00:00 2006, Uncontrolled Copy,

30、(c) BSIEN 15157:2006 (E) 13 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-section area varies with temperature and the variation is very difficult to measure. For this reason, the cr

31、oss-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 technique 9.3.1 Specimen mounting Install the test specimen in the gripping system with its longitudina

32、l 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 extensometer is positioned at ambient temperature, the extensometer output shall be adjusted to read zero

33、 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 taking expansion into account in order to be close to zero when at test temperature. 9.3.3 Heating the tes

34、t 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 applicable, for stabilization of the extensometer readout. Two procedures are possible: if test specimen temperature is measured d

35、uring 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 during the test, then it is necessary to use the relation between test specimen temperature and furnace temperature which has been est

36、ablished in 9.1. Ensure that the test specimen stays in the initial state of stress during heating. 9.3.4 Measurements Zero the load cell; zero the extensometer, 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

37、 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 control mode; Licensed Copy: Wang Bin, na, Thu Dec 14 05:53:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSIEN 15157:2006 (E) 14 record the number of cyc

38、les 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 is not possible, the following sequence

39、 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 Test validity The following circumsta

40、nces 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 shall invalidate a test for the determin

41、ation of the damage parameter: extensometer slippage; extensometer drift. 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 number of cycles required to obtain failure of the test spec

42、imen; f is the frequency, in hertz (Hz). Licensed Copy: Wang Bin, na, Thu Dec 14 05:53:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSIEN 15157:2006 (E) 15 10.2 Damage parameters Calculate the damage parameter Dnfor each recorded cycle, n, in accordance with the following equation: app1,appn,nEED =1 wh

43、ere Dnis the damage parameter at the nthfatigue cycle; 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). nresidualis equal to: (unl+l)/2 (see Figure 4 b).

44、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. Figures 4 a) to 4 c) represent three cases of cyclic fatigue of CMCs. NOTE Annex A shows the schematic evolution of E under differen

45、t 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 accordance with EN 1892, EN 1893 or EN 658-1. Licensed Copy: Wang Bin, na, Thu Dec 14 05:53:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSIE

46、N 15157:2006 (E) 16 a) R = 0 b) R 0 Key 1 strain () 2 stress () 3 cycle 1 4 Cycle n lloading unlunloading Figure 4 Fatigue stress-strain curves with a) R = 0, b) R 0 Licensed Copy: Wang Bin, na, Thu Dec 14 05:53:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSIEN 15157:2006 (E) 17 11 Test report The tes

47、t 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 European Standard, i.e. EN 15157; d) test specimen drawing or refer

48、ence; 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 (method A); j) maximum and minimum strain (method B); k) number

49、 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) damage parameter, if applicable; o) failure location of all the specimens used for obtaining the above results, if applicable. Licensed Copy: Wang Bin, na, Thu Dec 14 05:53:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSIEN 15157:2006 (E) 18 Annex A (in