1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 658-1:1998 The Euro
2、pean Standard EN 658-1:1998 has the status of a British Standard ICS 81.060.99 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Advanced technical ceramics Mechanical properties of ceramic composites at room temperature Part 1: Determination of tensile propertiesBS EN 658-1:199
3、8 This British Standard, having been prepared under the direction of the Sector Committee for Materials and Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 December 1998 BSI 1998 ISBN 0 580 30277 6 Amendments issued since publication Amd. No. Date
4、Text affected National foreword This British Standard is the English language version of EN 658-1:1998. It supersedes DD ENV 658-1:1993 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee RPI/13, Advanced technical ceramics, which has the responsibility t
5、o: aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations repr
6、esented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspond
7、ence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of
8、itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 13 and a back cover.CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secr
9、etariat: rue de Stassart 36, B-1050 Brussels 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 658-1:1998 E EUROPEAN STANDARD EN 658-1 NORME EUROPE ENNE EUROPA ISCHE NORM June 1998 ICS 81.160.99 Supersedes ENV 658-1:1993 Descrip
10、tors: composite materials, reinforcing materials, ceramics, mechanical properties, determination, tensile strength, tension tests, environmental tests English version Advanced technical ceramics Mechanical properties of ceramic composites at room temperature Part 1: Determination of tensile properti
11、es Ce ramiques techniques avance es Proprie te s me caniques des ce ramiques composites a tempe rature ambiante Partie 1: De termination des caracte ristiques en traction This European Standard was approved by CEN on 23 May 1998. CEN members are bound to comply with the CEN/CENELEC Internal Regulati
12、ons which stipulate 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 Central Secretariat or to any CEN member. This Europ
13、ean Standard exists 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 Central Secretariat has the same status as the official versions. CEN members are the natio
14、nal standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Page 2 EN 658-1:1998 BSI 1998 Foreword This European Standard has been prepared by Te
15、chnical Committee CEN/TC 184, Advanced technical ceramics, the Secretariat of which is held by BSI. This European Standard supersedes ENV 658-1:1993. 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 b
16、y December 1998, and conflicting national standards shall be withdrawn at the latest by December 1998. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, D
17、enmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom Contents Page 1 Scope 3 2 Normative references 3 3 Principle 3 4 Definitions and symbols 3 4.1 calibrated length, l 3 4.2 gauge length, L o
18、3 4.3 initial cross section area, A o 3 4.4 longitudinal deformation,DL 3 4.5 tensile strain, e 3 4.6 tensile stress, s 3 4.7 maximum tensile force, F t,m 3 4.8 tensile strength, s t,m 3 4.9 proportional limit stress, s o 3 4.10 proportionality ratio or pseudo-elastic modulus E p , elastic modulus,
19、E 4 4.11 cumulative damage energy,F 4 4.12 axial strain 4 4.13 bending strain 4 4.14 percent bending 4 Page 5 Apparatus 4 5.1 Test machine 4 5.2 Load train 4 5.3 Strain measurement 4 5.4 Data recording system 5 5.5 Micrometers 5 6 Test specimens 5 7 Test specimen preparation 8 7.1 Machining and prep
20、aration 8 7.2 Number of test specimens 8 8 Test procedure 8 8.1 Displacement rate 8 8.2 Measurement of test specimen dimensions 8 8.3 Testing technique 8 8.4 Test validity 8 9 Calculation of results 8 9.1 Test specimen origin 8 9.2 Tensile strength 8 9.3 Tensile strain at maximum tensile force 8 9.4
21、 Proportionality ratio or pseudo-elastic modulus, elastic modulus 8 9.5 Cumulative damage energy 9 10 Test report 9Page 3 EN 658-1:1998 BSI 1998 1) Published by JRC Institute for Advanced Materials, ISBN 92-826-9681-2, EUR 16138 EN. 1 Scope This standard specifies the conditions for the determinatio
22、n of tensile properties of ceramic matrix composite materials with continuous fibre reinforcement at ambient temperature. This standard applies to all ceramic matrix composites with a continuous fibre reinforcement, unidirectional (1D), bidirectional (2D), and tridirectional (xD, with 2 x# 3), loade
23、d along one principal axis of reinforcement. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and in the publications listed hereafter. For dated re
24、ferences, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 10002-2, Metallic materials Tensile testing Part 2:
25、 Verification of the force measuring system of the tensile testing machines. EN 10002-4, Metallic materials Tensile test Part 4: Verification of extensometers used in uniaxial testing. ISO 3611, Micrometer callipers for external measurements. ENV 1892, Advanced technical ceramics Mechanical properti
26、es of ceramic composites at high temperature under inert atmosphere Determination of tensile properties. ENV 1893, Advanced technical ceramics Mechanical properties of ceramic composites at high temperature in air at atmospheric pressure Determination of tensile properties. HTMTC 1) , Code of practi
27、ce Code of practice for the measurement of misalignment induced bending in uniaxially loaded tension compression test pieces. 3 Principle A test specimen of specified dimensions is loaded in tension. The test is performed at constant cross-head displacement rate, or constant deformation rate. NOTE T
28、he use of constant loading rate only gives a valid tensile curve when the material behaves linearly up to failure. The force and longitudinal deformation are measured and recorded simultaneously. 4 Definitions and symbols For the purposes of this European Standard, the following definitions apply: 4
29、.1 calibrated length, l the part of the test specimen which has uniform and minimum cross-section area 4.2 gauge length, L o initial distance between reference points on the test specimen in the calibrated length 4.3 initial cross-section area, A o initial cross-section of the test specimen within c
30、alibrated length 4.4 longitudinal deformation, DL increase in the gauge length between reference points under a tensile force. Its value corresponding to the maximum force shall be denotedDL t,m 4.5 tensile strain, e relative change in the gauge length defined as the ratio DL/L o . Its value corresp
31、onding to the maximum force shall be denoted e t,m 4.6 tensile stress, s the tensile force supported by the test specimen at any time in the test divided by the initial cross-section area 4.7 maximum tensile force, F t,m highest recorded tensile force in a tensile test on the test specimen when test
32、ed to failure 4.8 tensile strength, s t,m ratio of the maximum tensile force to the initial cross-section area 4.9 proportional limit stress, s o the greatest stress that the test specimen is capable of sustaining without any deviation from proportionality of stress to strainPage 4 EN 658-1:1998 BSI
33、 1998 4.10 proportionality ratio or pseudo-elastic modulus E p , elastic modulus, E the slope of the linear section of the stress-strain curve, if any. Examination of the stress-strain curves for ceramic matrix composites allows definition of the following cases: a) Material with a linear section in
34、 the stress-strain curve For ceramic matrix composites that have a mechanical behaviour characterised by a linear section, the proportionality ratio E p is defined as: E p (s 1 ,s 2 ) = (1) s 2 2 s 1 e 2 2 e 1 where: (e 1 ,s 1 ) and (e 2 ,s 2 ) lie near the lower and the upper limits of the linear s
35、ection of the stress-strain curve (see Figure 5). The proportionality ratio or pseudo-elastic modulus is termed the elastic modulus, E, in the single case where the linearity starts near the origin (see Figure 6). b) Material with nonlinear section in the stress-strain curve (see Figure 7). In this
36、case only stress-strain couples can be fixed. 4.11 cumulative damage energy,F the area under the force longitudinal deformation curve up to failure divided by the volume within the gauge length NOTE The cumulative damage energy is to be regarded as an indication for the ability of the material to su
37、stain damage rather than as a material property. For the characterization of the fracture mechanics of ceramic matrix composites suitable methods need to be developed. The determination of the cumulative damage energy as mentioned above will become obsolete as soon as standardized methods for the ch
38、aracterization of the fracture mechanics of these materials are available. 4.12 axial strain average of the longitudinal strain measured at the surface of the test specimen at specified locations (see the HTMTC code of practice) 4.13 bending strain the difference between the longitudinal strain at a
39、 given location on the test specimen surface and the axial strain (see the HTMTC code of practice) 4.14 percent bending the bending strain times 100 divided by the axial strain 5 Apparatus 5.1 Test machine The machine shall be equiped with a system for measuring the force applied to the test specime
40、n which shall conform to class of machine 1 or better in accordance with EN 10002-2. 5.2 Load train 5.2.1 General The load train is composed of the moveable and fixed cross-head, the loading rods, and the grips. Load train couplers may additionally be used to connect the grips to the loading rods. T
41、he load train shall align the specimen axis with the direction of load application without introducing bending or torsion in the specimen. The misalignment of the specimen shall be verified and documented according to the procedure described in the HTMTC Code of Practice. The maximum percent bending
42、 shall not exceed 5 at an axial strain of 5003 10 26 . 5.2.2 Grips The grips transmit the axial load applied by the testing machine to the specimen. They shall prevent slipping of the specimen in the gripping section. The selection of a particular type of grips depends on specimen design and critica
43、lly influences the alignment. NOTE 1 When the grip design relies on friction to transmit the axial load to the specimen, the use of an adjustable clamping pressure is recommended. NOTE 2 Care should be taken to avoid the introduction of torsion loading on the specimen when tightening the grips. 5.2.
44、3 Load train couplers Load train couplers may be used to connect the grips to the loading rods. Their primary function is to assure axial alignment of the grips in the loading train. NOTE 3 Load train couplers are of two types: fixed or non- fixed. Fixed couplers usually consist of angularity and/or
45、 concentricity adjusters. Non fixed couplers promote self-alignement of the load train upon movement of the cross-head. This self-aligning action is limited by the inherent friction between moving parts in the coupler. NOTE 4 The self-aligning action of non-fixed load train couplers may result in no
46、n-uniform loading of the unbroken ligament of the specimen after appearance of damage in the specimen, which can modify the shape of the tensile curve. NOTE 5 The use of well-aligned couplers and grips does not guarantee low bending in the specimen. The latter additionally depends on the type and op
47、eration of the grips, and on the type of the specimen. 5.3 Strain measurement For continuous measurement of the longitudinal deformation as a function of the applied force either strain gauges or a suitable extensometer complying with EN 10002-4 may be used. Measurement of longitudinal deformation o
48、ver a length as large as possible compatible with the calibrated length of the specimen is recommended.Page 5 EN 658-1:1998 BSI 1998 5.3.1 Strain gauges Strain gauges are used for the verification of the alignment on the specimen. They may also be used for measuring longitudinal deformation during t
49、esting. In both cases, the length of the strain gauges shall be such that the readings are not affected by local features on the surface of the specimen such as fibre crossovers. Care shall be taken to insure that the strain gauge readings are not influenced by the surface preparation and the adhesive used. 5.3.2 Extensometry The linearity tolerance of the extensometer shall be lower than 0,15 % of the extensometer range used. The commonly used type of extensometer is: 5.3.2.1 Mechanical extensometer For a mechanical
