1、BSI Standards PublicationBS ISO 18558:2015Fine ceramics (advancedceramics, advanced technicalceramics) Test method fordetermining elastic modulusand bending strength ofceramic tube and ringsBS ISO 18558:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18558
2、:2015.The UK participation in its preparation was entrusted to TechnicalCommittee RPI/13, Advanced technical ceramics.A 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 contrac
3、t. Users are responsible for its correctapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 81870 7ICS 81.060.30Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authorit
4、y of theStandards Policy and Strategy Committee on 31 May 2015.Amendments issued since publicationDate Text affectedBS ISO 18558:2015 ISO 2015Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for determining elastic modulus and bending strength of ceramic tube and ringsCrami
5、ques techniques Mthode dessai pour la dtermination du module lastique et de la rsistance en flexion des tubes et anneaux en cramiqueINTERNATIONAL STANDARDISO18558First edition2015-05-15Reference numberISO 18558:2015(E)BS ISO 18558:2015ISO 18558:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECT
6、ED DOCUMENT ISO 2015All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permiss
7、ion can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 18558:2015ISO 18558:2015(
8、E)Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 25 Apparatus . 25.1 Testing machine . 25.2 Data acquisition . 25.3 Dimension-measuring device. 26 Test pieces . 26.1 Test piece size 26.2 Test piece preparation 26.2.1 General 26.2.2 Test piece storage 36.2.3 Numb
9、er of test pieces 37 Test procedures . 37.1 Testing machine and loading speed 37.2 Elastic modulus measurement 37.3 Bending strength measurement 47.4 Temperature and relative humidity 48 Calculation of results . 58.1 Calculation of elastic modulus for split ring 58.1.1 Calculation of the elastic mod
10、ulus 58.1.2 Mean value and standard deviation for elastic modulus 58.2 Calculation of bending strength for split ring 68.2.1 8.2.1 Standard formula for bending strength68.2.2 Mean value and standard deviation for bending strength .69 Test report . 6Bibliography 8 ISO 2015 All rights reserved iiiCont
11、ents PageBS ISO 18558:2015ISO 18558:2015(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member
12、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 liaison with ISO, also take part in the work. ISO collaborates closely with the International Electr
13、otechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of
14、ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held r
15、esponsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information gi
16、ven for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the followi
17、ng URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 206, Fine ceramics.iv ISO 2015 All rights reservedBS ISO 18558:2015Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for determining elastic modulus and bending strength of cera
18、mic tube and rings1 ScopeThis International Standard specifies the testing method for determining the elastic modulus and bending strength of ceramic tubes or rings at ambient temperature by the compression tests on split ring pieces. Methods for test piece preparation, test modes and load rates, da
19、ta collection, and reporting procedures are addressed.This International Standard applies primary to the ceramic materials including monolithic fine ceramic, glass, whisker- or particulate reinforced ceramic composites, but not available for fibre reinforced ceramic composites. This test method may
20、be used for material research, quality control, and characterization and design data generation purpose.2 Normative referencesThe following referenced documents, in whole or in part, are normatively in this document and are indispensable to its application. For dated references, only the edition cit
21、ed applies. For undated references, the latest edition of the referenced document (including any amendments) applies.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
22、3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1elastic modulusratio of stress to strain, also known as Youngs modulus3.2bending strengthmaximum tensile stress at fracture of a split ring under compression3.3split ringtest piece which has the sh
23、ape of a split ring, prepared by cutting a gap from a ring pieceRrR-rbFigure 1 Schematic diagram of a split ring pieceINTERNATIONAL STANDARD ISO 18558:2015(E) ISO 2015 All rights reserved 1BS ISO 18558:2015ISO 18558:2015(E)3.4fracture loadcompression load applied on the split ring piece at fracture4
24、 PrincipleInstall a split ring test-piece on the fixture and keep the gap at the middle height. Under a symmetrically compressive load, stiffness of the split ring reflects the elastic modulus and the critical load to fracture reflects the fracture strength. For a given test piece in the range of el
25、asticity, the elastic modulus could be obtained from the slope of the loading-displacement curve and the test piece dimensions. Bending strength is computed from the critical load at fracture and the test piece dimensions.5 Apparatus5.1 Testing machineA suitable testing machine capable of applying a
26、 force to the test piece at a uniform displacement or loading rate shall be used. The testing machine shall comply with the values in ISO 7500-1. The measuring accuracy is 1 % or better and the calibration shall have been checked recently.5.2 Data acquisitionObtain the maximum load and at least auto
27、graphic record of the applied load versus the displacement of the split ring for elastic modulus tests. Obtain the critical load at fracture for strength tests.Digital chart recorders or data collection systems shall be used. The data acquisition system shall be with a precision of 1 % or better for
28、 load, and a precision of at least 0,001 mm or better for displacement measurement.5.3 Dimension-measuring deviceFor the determination of the test piece dimensions, a calibrated calliper or an alternative calibrated device with a resolution of 0,02 mm shall be used.6 Test pieces6.1 Test piece sizeTe
29、st piece geometry shall meet with 9111rRfor the validity of the calculation formulae. The gap of the split ring shall be sufficiently large (usually 2 mm to 3 mm) so that the ring will not be closed during the test before fracture in the strength test, but less than the one half of the inner diamete
30、r, as shown in Figure 1.The suitable width (axial length) for the split ring shall be satisfied with 0,2 b/R 1,0 and 10 50,/(),bRr .Measure the width, the outer radius, and the inner radius of each test piece in several places using a calibrated calliper. Compute the mean value of each one.6.2 Test
31、piece preparation6.2.1 GeneralThis International Standard permits two options for surface treatment in test piece preparation.2 ISO 2015 All rights reservedBS ISO 18558:2015ISO 18558:2015(E)I: Tubes property: no further surface preparation for evaluating the mechanical properties of existing ceramic
32、 tubes or rings, including as-fired, surface polished, or surface machined tubes.Cut the ceramic tube into several rings according to the size requirement in 7.1. Then grind and polish the cutting section faces of the ring to a parallelism of 0,02 mm or better. Clean the test pieces with alcohol or
33、pure water, etc. The edges of the test pieces shall be chamfered to avoid edge damage for strength tests. Chamfering is not important for the tests of elastic modulus. Then a slot width about 0,2 r is cut by using a cutting machine for ceramics.II: Material property: test piece is machined from tube
34、s or bulk ceramics, surface shall be ground and polished before cutting into rings.For a given ceramic tube, if surface treatment is in need, the grinding and polishing shall be performed parallel to the tangent direction of the tube first. Cut the ceramic tube into several rings according to the si
35、ze requirement in 7.1. And then, grind and polish the cutting section faces of the ring to a parallelism of 0,02 mm or better. Clean the test pieces with alcohol or pure water, etc. The edges of the test pieces shall be chamfered to avoid edge damage for strength tests. Chamfering is not important f
36、or the tests of elastic modulus. Then a slot width about 0,2 r is cut by using a cutting machine for ceramics.NOTE The aim of polishing is to minimize the damage created in the test pieces due to the preparation process.6.2.2 Test piece storageThe test pieces shall be handled with care to avoid the
37、introduction of damage after test piece preparation. Test pieces shall be stored separately and not allowed to impact or scratch each other.6.2.3 Number of test piecesA minimum of 6 test pieces is required for the tests. For a more detailed statistical analysis of the strength (e.g. Weibull analysis
38、), at least 30 pieces are recommended.7 Test procedures7.1 Testing machine and loading speedUse universal mechanical testing machine with a crosshead speed of 0,1 mm/min for the elastic modulus tests and 0,5 mm/min for the strength tests, respectively. The test piece shall contact well with the supp
39、orting and loading anvils.NOTE Suitable loading rate actually depends on the ring size, the test can be performed by position or load control so that the time to failure will be between 10 s to 60 s for the split ring test piece.7.2 Elastic modulus measurementTo measure the elastic modulus, put each
40、 test piece in the fixture, as shown in Figure 2. The middle of the gap shall be, as possible as, at the half height of ring. The test piece shall contact well with the supporting and loading anvils. Apply the test force at a specified rate of 0,1 mm/min and record the load increment in the scope of
41、 elastic deformation and the corresponding compressive displacement of the piece. The displacement increment is measured by digital micrometer or other devices with high accuracy in accordance with 5.2. The elastic modulus of the material is calculated according to the Formula (1). ISO 2015 All righ
42、ts reserved 3BS ISO 18558:2015ISO 18558:2015(E)PPP PPPPArRFigure 2 Schematic diagram of the split ring, loading mode and deformationPPPcFigure 3 Schematic diagram of a load-displacement curve7.3 Bending strength measurementTo measure the bending strength of the split ring, put each test piece in the
43、 fixture. The middle of the gap shall be at the half height of ring. The test piece shall contact well with the anvils. Apply the symmetrical test force at 0,5 mm/min crosshead rate, as shown in Figure 2, and record the peak value of the load. The typical loading-displacement curve is shown in Figur
44、e 3. The fracture starting point is usually near point A (maximum bending stress point) as shown in Figure 2. Otherwise, this strength test is invalid. The bending strength of the test piece can be calculated by the Formula (4).7.4 Temperature and relative humidityMeasure and record the laboratory a
45、mbient temperature and relative humidity during the test process.4 ISO 2015 All rights reservedBS ISO 18558:2015ISO 18558:2015(E)8 Calculation of results8.1 Calculation of elastic modulus for split ring8.1.1 Calculation of the elastic modulusThe standard formula for elastic modulus is:EbPRrRr=+34000
46、3pi(1)whereE is the elastic modulus, in GPa;P is the load increment in the scope of elastic deformation, in Newton (N); is the corresponding compressive displacement resulted from the P, in mm;R is the mean outer radius of split ring, in mm;r is the mean inner radius of split ring, in mm;b is the me
47、an width of test pieces, in mm.8.1.2 Mean value and standard deviation for elastic modulusThe mean elastic modulus, E , and the standard deviation, Se, are given by Formulae (2) and (3):EEnini=1,(2)SEEneini=12121()/(3)whereEiis the elastic modulus of the ith test piece;n is the total number of test
48、piece. ISO 2015 All rights reserved 5BS ISO 18558:2015ISO 18558:2015(E)8.2 Calculation of bending strength for split ring8.2.1 8.2.1 Standard formula for bending strengthThe standard formula for the bending strength is:br=+PbR RrRrRrcln(/)2(4)wherebris the bending strength, in MPa;Pcis the maximum l
49、oad to fracture, in N;R is the mean outer radius of split ring, in mm;r is the mean inner radius of split ring, in mm;b is the mean width of test pieces, in mm.8.2.2 Mean value and standard deviation for bending strengthThe mean bending strength, br, and the standard deviation, Ss, are given by Formulae (5) and (6):brinin=1(5)Snsinibr=12121()/(6)whereiis the bending strength of the ith test piece;n is the total number of test piece.9 Test reportThe test r
