EN 1007-7-2010 en Advanced technical ceramics - Ceramic composites - Methods of test for reinforcements - Part 7 Determination of the distribution of tensile strength and of tensil.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 1007-7:2010Advanced technical ceramics Ceramic composites Methods of test forreinforcementsPart 7: Determination of the distributionof tensile strength and of tensile strai

2、n tofailure of filaments within a multifilamenttow at high temperatureBS EN 1007-7:2010 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 1007-7:2010.The UK participation in its preparation was entrusted to TechnicalCommittee RPI/13, Advanced technical ceramics.A

3、list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2010ISBN 978 0 580 69222 2ICS 81.060.30Compliance with a Britis

4、h Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 2010Amendments issued since publicationDate Text affectedAugustEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 1007-7 July 2010 ICS

5、 81.060.30 Supersedes CEN/TS 1007-7:2006English Version Advanced technical ceramics - Ceramic composites - Methods of test for reinforcements - Part 7: Determination of the distribution of tensile strength and of tensile strain to failure of filaments within a multifilament tow at high temperature C

6、ramiques techniques avances - Cramiques composites - Mthodes dessai pour renforts - Partie 7: Dtermination de la distribution de la rsistance en traction et de la dformation de traction la rupture des filaments dans un fil haute temprature Hochleistungskeramik - Keramische Verbundwerkstoffe - Verfah

7、ren zur Prfung der Faserverstrkungen - Teil 7: Bestimmung der Verteilung von Zugfestigkeit und Zugdehnung von Fasern im Faserbndel bei hoher Temperatur This European Standard was approved by CEN on 4 June 2010. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate

8、 the conditions for giving this European Standard the status of a national standard 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 exis

9、ts in three official versions (English, French, German). A version in any other language 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 b

10、odies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United

11、Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 1007-7:2010: EE

12、N 1007-7:2010 (E) 2 Contents Page Foreword 31 Scope 42 Normative references 43 Terms and definitions .54 Symbols and abbreviations 75 Principle 76 Significance and use .87 Apparatus .87.1 Test machine 87.2 Load train 87.3 Adhesive .87.4 Test chamber 97.5 Set-up for heating 97.6 Temperature measureme

13、nt .97.7 Data recording system 98 Test procedure .98.1 Test specimens 98.2 Test specimen preparation 108.3 Number of test specimens . 128.4 Test Procedure 138.5 Calculation of results . 17Annex A (informative) Derivation of the Youngs modulus of the hot part of the tow 25Bibliography . 26BS EN 1007-

14、7:2010EN 1007-7:2010 (E) 3 Foreword This document (EN 1007-7:2010) has been prepared by Technical Committee CEN/TC 184 “Advanced 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 identica

15、l text or by endorsement, at the latest by January 2011, and conflicting national standards shall be withdrawn at the latest by January 2011. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held res

16、ponsible for identifying any or all such patent rights. This document supersedes CEN/TS 1007-7:2006. EN 1007, Advanced technical ceramics Ceramic composites. Methods of test for reinforcements, has been prepared in 7 parts: Part 1: Determination of size content; Part 2: Determination of linear densi

17、ty; Part 3: Determination of filament diameter and cross-section area; Part 4: Determination of tensile properties of filaments at ambient temperature; Part 5: Determination of distribution of tensile strength and of tensile strain to failure of filaments within a multifilament tow at ambient temper

18、ature; Part 6: Determination of tensile properties of filaments at high temperature; Part 7: Determination of the distribution of tensile strength and tensile strain to failure of filaments within a multifilament tow at high temperature. According to the CEN/CENELEC Internal Regulations, the nationa

19、l standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, No

20、rway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 1007-7:2010EN 1007-7:2010 (E) 4 1 Scope This European standard specifies the conditions, apparatus and procedure for determining the distribution of tensile strength and tensile strain to fa

21、ilure of ceramic filaments in multifilament tows at high temperature in air, vacuum or a controlled inert atmosphere. This part of EN 1007 applies to tows of continuous ceramic filaments, which are assumed to act freely and independently under loading and behave linearly elastic up to failure. Two m

22、ethods are proposed depending on the temperature of the ends of the tow: a) hot end method; NOTE 1 The application of the hot end method is restricted by ceramic glues with sufficient shear strengths at the test temperature. Current experience with this technique is limited to 1 300 C, because of th

23、e maximum application temperature of ceramic glues. b) cold end method. NOTE 2 The cold-end method is limited to 1 700 C in air and 2 000 C in inert atmosphere because of the limits of furnaces. Both methods allow for a failure rate in the determination of distribution of tensile strain and tensile

24、strength. 2 Normative references The following referenced documents are indispensable 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 1007-2, Advan

25、ced technical ceramics Ceramic composites Methods of test for reinforcement Part 2: Determination of linear density CEN/TR 13233:2007, Advanced technical ceramics Notations and symbols EN 60584-1, Thermocouples Part 1: Reference tables (IEC 60584-1:1995) EN 60584-2, Thermocouples; Part 2: tolerances

26、 (IEC 60584-2:1982 + A1:1989) EN ISO 7500-1:2004, Metallic materials Verification of static uniaxial testing machines Part 1: Tension/ compression testing machines Verification and calibration of the force-measuring system (ISO 7500-1:2004) ISO 10119, Carbon fibre Determination of density BS EN 1007

27、-7:2010EN 1007-7:2010 (E) 5 3 Terms and definitions For the purposes of this document, the terms and definitions given in CEN/TR 13233:2007 and the following apply. 3.1 test temperature T temperature of the filament at the centre of the gauge length 3.2 lengths initial distances between two referenc

28、e points on the tow, disregarding thermal and mechanical strains 3.2.1 gauge length L0part of the tow between the gripped ends, where the temperature variation is within 20 K of the test temperature 3.2.2 test specimen length Lf. initial distance between the gripped ends of the tow 3.2.3 uniformly h

29、eated length Lhlength of the heated zone within which the temperature variation is within 20 K of the test temperature 3.2.4 cold zone length Lclength of the tow, which is not uniformly heated 3.3 initial cross sectional area A0sum of the cross sectional areas of all the filaments in the tow 3.4 tow

30、 elongation L increase of the gauge length between the two reference points on the tow 3.5 tow strain ratio of the tow elongation L to the gauge length Lo3.6 tow maximum tensile force Ftowhighest recorded tensile force on the test specimen when tested to failure BS EN 1007-7:2010EN 1007-7:2010 (E) 6

31、 3.7 tow strength towratio of the tow maximum tensile force to the cross sectional area of all unbroken filaments at maximum tensile force, Ftow3.8 force at step j Fjforce applied on the test specimen at step j 3.9 filament strain jstrain at step j in the non-linear parts of the force-displacement c

32、urve 3.10 filament strength jratio of the tensile force to the cross sectional area of all unbroken filaments at step j in the non-linear parts of the force-displacement curve 3.11 average filament rupture strain rstatistical average rupture strain of the filaments in the tow for each test determine

33、d from the Weibull strain distribution parameters of the filaments 3.12 overall average filament rupture strain rarithmetic mean of the average filament rupture strains 3.13 average filament strength rstatistical average strength of the filaments in the tow for each test determined from the Weibull

34、strength distribution parameters of the filaments 3.14 overall average filament strength rarithmetic mean of the average filament strengths 3.15 Compliances 3.15.1 initial total compliance Ctinverse slope of the linear part of the force-displacement curve BS EN 1007-7:2010EN 1007-7:2010 (E) 7 3.15.2

35、 instantaneous total compliance Ct,jinverse slope of the secant at any point j in the non-linear part of the force-displacement curve NOTE The slope is taken from a line through any point of the force-displacement curve and the intersection point of the line of the initial total compliance with the

36、abscissa (true origin). 3.15.3 load train compliance Clratio of the cross head displacement to the force, excluding any contribution of the test specimen to the displacement during the tensile test 3.15.4 cold zone compliance Ccratio of the increase in test specimen length in the cold zone length Lc

37、to the corresponding force during the tensile test 3.15.5 hot zone compliance Chratio of the increase in test specimen length in the uniformly heated length Lhto the corresponding force during the tensile test 4 Symbols and abbreviations Ctowis the instantaneous total compliance of the tow at maximu

38、m tensile force. Ehis the elastic modulus (Youngs modulus) of the uniformly heated part of the tow. Ecis the elastic modulus (Youngs modulus) of the cold part of the tow. 5 Principle A multifilament tow is heated to the test temperature and loaded in tension. The test is performed at a constant disp

39、lacement rate up to failure. Force and cross-head displacement are measured and recorded simultaneously. When required, the longitudinal deformation is derived from the cross-head displacement using a compliance correction. From the force-displacement curve, the two-parameter Weibull distribution of

40、 the rupture strain and distribution of the rupture strength of the filaments is obtained by sampling the non-linear parts of the curve at discrete intervals j, which correspond to an increasing number of failed filaments in the tow. The test duration is limited to reduce time dependent effects. Two

41、 methods can be used. The first method (hot-end method) consists of heating the tow over its total length. The second method (cold end method) consists of heating only a part of the test specimen length, the temperature profile of which is used to define the gauge length. The application of this met

42、hod requires the realisation of three different heated zone lengths. BS EN 1007-7:2010EN 1007-7:2010 (E) 8 6 Significance and use The measurement of strain directly on the tow is difficult, so it is usually achieved indirectly via a compliance measurement which includes contributions of the loading

43、train, grips, tab materials, etc. These contributions shall be taken into account to achieve a correct analysis. When it is possible to measure the tow elongation directly (by using a suitable extensometer system) this correction is not needed. The calculation of the results in Clause 7 also applies

44、 in this case by setting the load train compliance equal to zero. The evaluation method is based on an analysis of the non-linear increasing and decreasing parts of the force displacement curve. These parts are caused by progressive filament failures during the test, which is encouraged by a high st

45、iffness of the loading and gripping system. When the force-displacement curve does not show these non-linear parts, the evaluation method of this part of EN 1007 cannot be applied. The distribution of filament failure strains does not depend on the number of filaments in the tow and is hence not aff

46、ected by the number of filaments which are broken before the test. The determination of the filament strength distribution requires knowledge of the initial cross sectional area of the tow and because the number of unbroken filaments within the tow prior to the test is usually unknown, the values fo

47、r the filament strength represent a lower bound to these quantities. Also, the variation in the filament diameter, which affects the strength values, is not accounted for. a) Hot end method: for the hot end method, the gauge length, defined as the uniformly heated length, equals the test specimen le

48、ngth. NOTE 1 Subjecting the whole length of a tow to temperatures well above 1 000 C, however, makes it difficult to fix the ends of the test specimen into appropriate temperature proof extensions. b) Cold end method: for the cold end method, the test specimen length is the sum of the cold and the h

49、ot parts of the tow, with the gauge length is defined as the uniformly heated length. The temperature gradient zones along the tow axis are neglected. NOTE 2 In this method, the problems associated with heating the clamps are avoided by heating only a central part of the tow and by keeping the junction at the ends of the test specimen at room temperature. This allows similar test specimen designs and organic resins to be used as