1、Rubber, vulcanized Determination of tension fatigue BS ISO 6943:2017 BSI Standards Publication WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06 ISO 2017 Rubber, vulcanized Determination of tension fatigue Caoutchouc vulcanis Dtermination de la fatigue en traction INTERNATIONAL STANDARD ISO 6
2、943 Fourth edition 2017-08 Reference number ISO 6943:2017(E) National foreword This British Standard is the UK implementation of ISO 6943:2017. It supersedes BS ISO 6943:2011, which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee PRI/22, Testing and analysi
3、s of rubber. A list of organizations represented on this committee 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 application. The British Standards Institution 2017 Published
4、 by BSI Standards Limited 2017 ISBN 978 0 580 97196 9 ICS 83.060 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 September 2017. Amendments/corrigenda issued
5、 since publication Date Text affected BRITISH STANDARD BS ISO 6943:2017 ISO 2017 Rubber, vulcanized Determination of tension fatigue Caoutchouc vulcanis Dtermination de la fatigue en traction INTERNATIONAL STANDARD ISO 6943 Fourth edition 2017-08 Reference number ISO 6943:2017(E) BS ISO 6943:2017 IS
6、O 6943:2017(E)ii ISO 2017 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in Switzerland All 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 photocop
7、ying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 74
8、9 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.org BS ISO 6943:2017 ISO 6943:2017(E)ii ISO 2017 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherw
9、ise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office C
10、h. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.orgISO 6943:2017(E)Foreword iv 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 2 4 Principle 2 5 Apparatus . 2 6 Calibration 3 7 Test piece 3 7.1 Dimensi
11、ons . 3 7.1.1 General 3 7.1.2 Dumb-bell test piece . 3 7.1.3 Ring test piece 5 7.2 Number of test pieces . 5 7.3 Storage and conditioning . 5 8 Test conditions . 6 8.1 Test strains . 6 8.2 Test frequency . 6 8.3 Test temperature . 6 8.4 Test atmosphere 6 9 Procedure. 7 9.1 Marking of dumb-bell test
12、pieces 7 9.2 Measurement of test pieces . 7 9.2.1 Dumb-bell test pieces 7 9.2.2 Ring test pieces 7 9.3 Insertion of test pieces in the fatigue-testing machine 7 9.3.1 Dumb-bell test pieces 7 9.3.2 Ring test pieces 8 9.4 Determination of fatigue life . 8 9.5 Measurement of set and maximum strain afte
13、r cycling 8 9.6 Measurement of maximum stress and maximum strain energy density . 9 10 Expression of results .10 10.1 Calculation of fatigue life .10 10.2 Calculation of set 10 10.3 Calculation of maximum strain 11 10.4 Calculation of maximum stress 11 10.5 Calculation of strain energy density 11 11
14、 Test report 12 Annex A (informative) Explanatory notes 13 Annex B (normative) Calibration schedule 16 Bibliography .18 ISO 2017 All rights reserved iii Contents Page BS ISO 6943:2017 ISO 6943:2017(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of nati
15、onal standards bodies (ISO member bodies). The work of preparing 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. Internat
16、ional organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intend
17、ed 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 ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www .
18、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 responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document
19、 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 given for the convenience of users and does not constitute an endorsement. For an explanation on the voluntary nature of standards, th
20、e meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www .iso .org/ iso/ foreword .html. This document was prepare
21、d by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 2, Testing and analysis. This fourth edition cancels and replaces the third edition (ISO 6943:2011), of which it constitutes a minor revision to update the normative references in Clause 2.iv ISO 2017 All rights reserved
22、 BS ISO 6943:2017 ISO 6943:2017(E) Foreword ISO (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 body in
23、terested 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 Electrotechni
24、cal 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 ISO do
25、cuments 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 res
26、ponsible 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
27、given for the convenience of users and does not constitute an endorsement. For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) pr
28、inciples in the Technical Barriers to Trade (TBT) see the following URL: www .iso .org/ iso/ foreword .html. This document was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 2, Testing and analysis. This fourth edition cancels and replaces the third edition (I
29、SO 6943:2011), of which it constitutes a minor revision to update the normative references in Clause 2.iv ISO 2017 All rights reserved INTERNATIONAL ST ANDARD ISO 6943:2017(E) Rubber, vulcanized Determination of tension fatigue WARNING 1 Persons using this document should be familiar with normal lab
30、oratory practice. This document does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions. WA R N I N G 2 C er t a
31、 i n p ro c ed ure s s p e c i f ie d in t his do c u ment m i g ht i nvol ve t he u se or g en er a t i o n of substances or the generation of waste, that could constitute a local environmental hazard. Reference should be made to appropriate documentation on safe handling and disposal after use. 1
32、Scope This document specifies a method for the determination of the resistance of vulcanized rubbers to fatigue under repeated tensile deformations, the test piece size and frequency of cycling being such that there is little or no temperature rise. Under these conditions, failure results from the g
33、rowth of a crack that ultimately severs the test piece. The method is restricted to repeated deformations in which the test piece is relaxed to zero strain for part of each cycle. Analogous fatigue processes can occur under repeated deformations which do not pass through zero strain and also, in cer
34、tain rubbers, under static deformation, but this document does not apply to these conditions. The method is believed to be suitable for rubbers that have reasonably stable stress-strain properties, at least after a period of cycling, and that do not show undue stress softening or set, or highly visc
35、ous behaviour. Materials that do not meet these criteria might present considerable difficulties from the points of view of both experiment and interpretation. For example, for a rubber that develops a large amount of set during the fatigue test, the test strain will be ill-defined and the fatigue l
36、ife is likely to differ markedly under constant maximum load and constant maximum extension conditions; how the results for such a rubber should be interpreted or compared with those for other rubbers, has not been established by basic work. As a general guide, a rubber for which the set determined
37、in accordance with 9.5 and 10.2 exceeds 10 % is likely to fall into this category. For this reason, the method is not considered suitable for most thermoplastic elastomers. Similar considerations apply with regard to other changes in elasticity behaviour during testing. This fatigue test is distinct
38、 from the flexometer tests described in the various parts of ISO 4666, where fatigue breakdown occurs under the simultaneous action of stress and temperature. Advantages over the De Mattia flex cracking and cut growth test (see ISO 132) include the following: the test yields quantitative results whi
39、ch do not depend on operator interpretation and which can be recorded automatically; the initial deformation is clearly defined and can readily be varied to suit different applications. Great caution is necessary in attempting to relate standard test results to service performance since the comparat
40、ive fatigue resistance of different vulcanizates can vary according to the test conditions used and to the basis by which the results are compared. Guidance on the selection of test conditions and on the interpretation of results is given in Annex A. 2 Normative references The following documents ar
41、e referred to in the text in such a way that some or all of their content constitutes requirements 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. ISO 2017 All rights res
42、erved 1 BS ISO 6943:2017 ISO 6943:2017(E) ISO 18899:2013, Rubber Guide to the calibration of test equipment ISO 23529, Rubber General procedures for preparing and conditioning test pieces for physical test methods 3 T erms an d definiti ons For the purposes of this document, the following terms and
43、definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: IEC Electropedia: available at h t t p :/ www .electropedia .org/ ISO Online browsing platform: available at h t t p :/ www .iso .org/ obp 3.1 fatigue life number of cycles require
44、d to break a test piece repeatedly deformed to a prescribed tensile strain 3.2 tension fatigue fracture, through crack growth, of a component or test piece subjected to a repeated tensile deformation 4 Principle Dumb-bell or ring test pieces are repeatedly deformed in simple extension until they fai
45、l by breaking. The test pieces are relaxed to zero strain for part of each cycle. The number of deformation cycles to failure, defined as the fatigue life, is determined as a function of the maximum strain and, if required, as a function of the maximum stress or strain energy density imposed during
46、the test. 5 Apparatus 5.1 Fatigue-testing machine The fatigue-testing machine shall provide a reciprocating motion at a frequency which shall normally be within the range 1 Hz to 5 Hz. For testing dumb-bell test pieces, the machine shall be provided with clamps that grip the test piece sufficiently
47、firmly to prevent slippage, irrespective of the magnitude of the strain applied. For testing ring test pieces, each station on the machine shall be provided with two pairs of rollers, one pair fixed to the body of the machine and the other to the reciprocating part. To minimize friction, the rollers
48、 shall be fabricated from stainless or chromium-plated steel, well-polished and fitted with free- running ball races. The roller arrangement shall be such that the test pieces are held securely in place over the rollers throughout the test. The stroke of the machine and the position of the fixed cla
49、mps or rollers shall be adjustable to provide a range of test strains. In all cases, the test piece shall be relaxed to zero strain for part of each cycle. The fixed clamps or rollers should preferably be fitted with contacts or other means of operating counters to register the number of cycles to failure of each test piece. If it is required to determine the maximum stress of the cycle, manual or automatic means for measurement of the load shall be provided. Stress-strain properties and strain energy density under tes
