1、 Reference number ISO 20505:2005(E) ISO 2005INTERNATIONAL STANDARD ISO 20505 First edition 2005-10-01 Fine ceramics (advanced ceramics, advanced technical ceramics) Determination of the interlaminar shear strength of continuous-fibre-reinforced composites at ambient temperature by the compression of
2、 double-notched test pieces and by the Iosipescu test Cramiques techniques Dtermination de la rsistance au cisaillement interlaminaire des composites renforcs de fibres connues temprature ambiente par compression dprouvettes doublement entailles et par lessai de Iosipescu ISO 20505:2005(E) PDF discl
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6、ghts reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of t
7、he requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2005 All rights reservedISO 20505:2005(E) ISO 2005 All rights reserved iii Contents Page Foreword. v 1 Scope1 2 No
8、rmative references1 3 Terms and definitions .1 4 Symbols and abbreviated terms 2 5 Principle3 6 Interferences5 6.1 Test environment.5 6.2 Preparation of test pieces.5 6.3 Bending.5 6.4 Failures outside gauge section6 6.5 Notch separation6 6.6 Specimen clamping.6 6.7 Friction6 7 Apparatus.6 7.1 Testi
9、ng machines.6 7.2 Data acquisition .6 7.3 Dimension-measuring devices.6 7.4 Test fixtures7 8 Test piece.10 8.1 Test piece geometry 10 8.1.1 Double-notched test piece10 8.1.2 Iosipescu test piece.10 8.2 Test piece preparation 11 8.2.1 Customary practices.11 8.2.2 Standard procedures.11 8.2.3 Handling
10、 precautions 12 8.3 Number of test pieces .12 9 Precautionary statement.12 10 Test conditions 12 10.1 Test modes and rates12 10.1.1 Displacement rate12 10.1.2 Load rate.12 11 Procedure.12 11.1 Test piece dimensions 12 11.2 Preparations for testing 13 11.3 Conducting the test .13 11.3.1 Mount the tes
11、t piece in the test fixture13 11.3.2 Begin data acquisition. .13 11.4 Completion of testing14 11.5 Post test15 12 Calculation of results 15 12.1 Shear strength15 12.1.1 Double-notched test piece15 12.1.2 Iosipescu test piece.15 12.2 Statistics.16 ISO 20505:2005(E) iv ISO 2005 All rights reserved13 T
12、est report 16 Annex A (informative) Results of round-robin tests . 18 Bibliography . 20 ISO 20505:2005(E) ISO 2005 All rights reserved v Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing
13、 International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liais
14、on with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of te
15、chnical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is dr
16、awn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 20505 was prepared by Technical Committee ISO/TC 206, Fine ceramics. INTERNATIONAL STANDARD ISO 20505:2005(E) IS
17、O 2005 All rights reserved 1 Fine ceramics (advanced ceramics, advanced technical ceramics) Determination of the interlaminar shear strength of continuous-fibre-reinforced composites at ambient temperature by the compression of double-notched test pieces and by the Iosipescu test 1 Scope This Intern
18、ational Standard specifies a method for the determination of interlaminar shear strength of continuous-fibre-reinforced ceramic composites at ambient temperature, by the compression of a double- notched test piece or by the Iosipescu test. Methods for test piece fabrication, testing modes and rates
19、(load rate or displacement rate), data collection, and reporting procedures are addressed. This International Standard applies primarily to advanced ceramic or glass-matrix composites with continuous- fibre reinforcement having uni-directional (1-D) or bi-directional (2-D) fibre architecture. This t
20、est method does not address composites with (3-D) fibre architecture or discontinuous-fibre-reinforced, whisker-reinforced or particulate-reinforced ceramics. NOTE 1 Values expressed in this International Standard are in accordance with the International System of Units (SI). NOTE 2 This Internation
21、al Standard is based on ASTM C1292. 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)
22、 applies. ISO 3611, Micrometer callipers for external measurement ISO 7500-1, Metallic materials Verification of static uniaxial testing machines Part 1: Tension/compression testing machines Verification and calibration of the force-measuring system ASTM C1292, Standard Test Method for Shear Strengt
23、h of Continuous Fiber-Reinforced Advanced Ceramics at Ambient Temperatures 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 fine ceramic (advanced ceramic, advanced technical ceramic) highly engineered, high-performance predominately non-metal
24、lic, inorganic, ceramic material having specific functional attributes ISO 20505:2005(E) 2 ISO 2005 All rights reserved3.2 continuous-fibre-reinforced ceramic composite CFCC ceramic matrix composite in which the reinforcing phase consists of a continuous fibre, continuous yarn, or a woven fabric 3.3
25、 shear-failure load maximum load required to fracture a shear-loaded test piece 3.4 shear strength maximum shear stress which a material is capable of sustaining NOTE Shear strength is calculated from the shear-fracture load and the shear-loaded area. 4 Symbols and abbreviated terms The symbols used
26、 throughout this International Standard and their designations are given in Table 1. Table 1 Symbols and designations Symbol Designation Unit References L Test piece length mm Tables 2, 3 h Distance between notches mm Tables 2, 3 Equations 2, 4 w Test piece width mm Tables 2, 3 Equation 2 t Test pie
27、ce thickness mm Tables 2, 3 Equation 4 d Notch width, double-notched test piece mm Table 2 R Notch radius, Iosipescu test piece mm Table 3 Notch angle, Iosipescu test piece Table 3 n Number of valid tests 1 Equations 5, 6 subclause 12.2 P maxMaximum load N Equations 1, 3 A 1Shear area for double-not
28、ched test piece mm 2Equations 1, 2 A 2Shear area for Iosipescu test piece mm 2Equations 3, 4 ILInterlaminar shear strength MPa Equations 1, 3 X Mean value MPa Equations 5, 6, 7 SD Standard deviation MPa Equations 6, 7 CV Coefficient of variation 1 Equation 8 ISO 20505:2005(E) ISO 2005 All rights res
29、erved 3 5 Principle This International Standard is for material development, material comparison, quality assurance, characterization, reliability and design data generation. The interlaminar shear strength of continuous-fibre- reinforced ceramic composites, as determined by this International Stand
30、ard, can be measured by the compression of double-notched test pieces or by the Iosipescu test. In the case of the former, a double- notched test piece of uniform width is loaded in compression to induce failure by shear between two centrally located notches machined halfway through the thickness an
31、d spaced a fixed distance apart on opposing faces. Schematics of the test setup and the test piece are shown in Figures 1 and 2. Figure 1 Schematic of double-notched test piece subjected to compressive loading ISO 20505:2005(E) 4 ISO 2005 All rights reservedDimensions in millimetres Figure 2 Geometr
32、y and dimensions of double-notched test piece For the Iosipescu test, the shear strength is determined by loading a test coupon in the form of a rectangular flat strip with symmetric, centrally located V-notches using a mechanical testing machine and an asymmetric four-point bending fixture. Failure
33、 of the test piece occurs by shear between the V-notches. Schematics of the test setup and test piece are shown in Figures 3 and 4. Figure 3 Schematic of Iosipescu test piece subjected to asymmetric four-point bending loading ISO 20505:2005(E) ISO 2005 All rights reserved 5 Dimensions in millimetres
34、 Figure 4 Geometry and dimensions of Iosipescu test piece 6 Interferences 6.1 Test environment The test environment may have an influence on the measured shear strength. In particular, the behaviour of materials susceptible to slow-crack-growth fracture will be strongly influenced by the test enviro
35、nment and testing rate. Testing to evaluate the maximum strength potential of a material shall be conducted in inert environments and/or at sufficiently rapid testing rates, so as to minimize slow-crack-growth effects. Conversely, testing can be conducted in environments and testing modes and rates
36、representative of service conditions, to evaluate material performance under those conditions. When testing is conducted in uncontrolled ambient air with the objective of evaluating maximum strength potential, relative humidity and temperature shall be monitored and reported. 6.2 Preparation of test
37、 pieces Preparation of test pieces, although normally not considered a major concern with continuous-fibre-reinforced ceramic composites, can introduce fabrication flaws which may have pronounced effects on the mechanical properties and behaviour (e.g. shape and level of the resulting load-displacem
38、ent curve and shear strength). Machining damage introduced during test piece preparation can be either a random interfering factor in the determination of shear strength of pristine material, or an inherent part of the strength characteristics to be measured. Universal or standardized test methods o
39、f surface preparation do not exist. Final machining steps may, or may not, negate machining damage introduced during the initial machining. Thus, the history of test piece fabrication may play an important role in the measured strength distributions and shall be reported. 6.3 Bending Bending of unia
40、xially loaded shear test pieces (during the compression of double-notched test pieces) can cause or promote non-uniform stress distributions that may alter the desired uniform state of stress during the test. ISO 20505:2005(E) 6 ISO 2005 All rights reserved6.4 Failures outside gauge section Fracture
41、s that initiate outside the uniformly stressed gauge section of a test piece may be due to extraneous stresses introduced by improper loading configurations, or strength-limiting features in the microstructure of the test piece. Such non-gauge-section fractures will constitute invalid tests. 6.5 Not
42、ch separation For the evaluation of the interlaminar shear strength by the compression of a double-notched test piece, the distance between the notches has an effect on the maximum load and therefore on the interlaminar shear strength. It has been found that the stress distribution in the test piece
43、 is independent of the distance between the notches when the notches are far apart. However, when the distance between the notches is such that the stress fields around the notches interact, the measured interlaminar shear strength increases. Because of the complexity of the stress field around each
44、 notch and its dependence on the properties and homogeneity of the material, it is recommended to perform a series of tests on test pieces with different spacing between the notches, to determine their effect on the measured interlaminar shear strength. 6.6 Specimen clamping Because the purpose of t
45、he jaws is to maintain the test piece in place and to prevent buckling, excessive clamping force with the jaws of the fixture during the compression of double-notched test pieces will reduce the stress concentration around the notches and therefore artificially increase the measured interlaminar she
46、ar strength. In the case of the Iosipescu fixture, avoid over-tightening the jaws because it induces undesirable pre-loading and may damage some materials. 6.7 Friction Many fixtures for both the compression of double-notched test pieces and the Iosipescu test incorporate an alignment mechanism in t
47、he form of a guide rod and a linear roller bearing. Excessive free play or excessive friction in this mechanism may introduce spurious moments that will alter the ideal loading conditions. 7 Apparatus 7.1 Testing machines The testing machine shall be verified in accordance with ISO 7500-1 and shall
48、be at least grade 1,0. 7.2 Data acquisition Obtain at least an autographic record of applied load and cross-head displacement versus time, using either analogue chart recorders or digital data acquisition systems. Recording devices shall be accurate to within 1 % of the selected range for the testin
49、g equipment including readout unit, and have a minimum data acquisition rate of 10 Hz with a response of 50 Hz deemed more than sufficient. 7.3 Dimension-measuring devices Micrometers and other devices used for measuring linear dimensions shall be accurate and precise to at least 0,01 mm and shall be in accordance with ISO 3611. To obtain consistent measurements of test piece dimensions, use a flat, anvil-type micrometer. Ball-tipped or sharp anvil micrometers are not recommended for woven continuous-fibr
