1、Rubber, vulcanized Determination of tension fatigueBS ISO 6943:2017BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06 ISO 2017Rubber, vulcanized Determination of tension fatigueCaoutchouc vulcanis Dtermination de la fatigue en tractionINTERNATIONALSTANDARDISO6943Fourth
2、 edition2017-08Reference numberISO 6943:2017(E)National forewordThis 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 It supersedes BS ISO 6943:2011, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee PRI/22, Testing and analysis of rubber.A li
3、st 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 by BSI Standards
4、Limited 2017ISBN 978 0 580 97196 9ICS 83.060Compliance 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 since publicationDate
5、Text affectedBRITISH STANDARDBS ISO 6943:2017 ISO 2017Rubber, vulcanized Determination of tension fatigueCaoutchouc vulcanis Dtermination de la fatigue en tractionINTERNATIONAL STANDARDISO6943Fourth edition2017-08Reference numberISO 6943:2017(E)BS ISO 6943:2017ISO 6943:2017(E)ii ISO 2017 All rights
6、reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in SwitzerlandAll 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
7、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 officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.org
8、www.iso.orgBS ISO 6943:2017ISO 6943:2017(E)ii ISO 2017 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in SwitzerlandAll 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 mec
9、hanical, 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 officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, Sw
10、itzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgISO 6943:2017(E)Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 24 Principle 25 Apparatus . 26 Calibration 37 Test piece 37.1 Dimensions . 37.1.1 General 37.1.2 Dumb-bell test piece . 37.1.3 Ring tes
11、t piece 57.2 Number of test pieces . 57.3 Storage and conditioning . 58 Test conditions . 68.1 Test strains . 68.2 Test frequency . 68.3 Test temperature . 68.4 Test atmosphere 69 Procedure. 79.1 Marking of dumb-bell test pieces 79.2 Measurement of test pieces . 79.2.1 Dumb-bell test pieces 79.2.2 R
12、ing test pieces 79.3 Insertion of test pieces in the fatigue-testing machine 79.3.1 Dumb-bell test pieces 79.3.2 Ring test pieces 89.4 Determination of fatigue life . 89.5 Measurement of set and maximum strain after cycling 89.6 Measurement of maximum stress and maximum strain energy density . 910 E
13、xpression of results .1010.1 Calculation of fatigue life . 1010.2 Calculation of set 1010.3 Calculation of maximum strain 1110.4 Calculation of maximum stress 1110.5 Calculation of strain energy density 1111 Test report 12Annex A (informative) Explanatory notes 13Annex B (normative) Calibration sche
14、dule 16Bibliography .18 ISO 2017 All rights reserved iiiContents PageBS ISO 6943:2017ISO 6943:2017(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
15、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 liaison with ISO, also take part in the wo
16、rk. ISO collaborates closely with the International Electrotechnical 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 diff
17、erent 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 .iso .org/ directives).Attention is drawn to the possibility that some of the elements of this document
18、 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 will be in the Introduction and/or on the ISO list of patent declarations received (see www .iso .org/
19、 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, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information
20、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 prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 2, Testing and analysis.Th
21、is 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 reservedBS ISO 6943:2017ISO 6943:2017(E)ForewordISO (the International Organization for Standardization) is a world
22、wide 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 interested in a subject for which a technical committee has been established has the right to be represented on t
23、hat committee. International 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 doc
24、ument 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 documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directi
25、ves, 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 responsible for identifying any or all such patent rights. Details of any patent rights identified during the develo
26、pment 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 given for the convenience of users and does not constitute an endorsement.For an explanation on the voluntary natu
27、re 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) principles in the Technical Barriers to Trade (TBT) see the following URL: www .iso .org/ iso/ foreword .html.This do
28、cument 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 (ISO 6943:2011), of which it constitutes a minor revision to update the normative references in Clause 2.iv ISO 2017 Al
29、l rights reserved INTERNATIONAL STANDARD ISO 6943:2017(E)Rubber, vulcanized Determination of tension fatigueWARNING 1 Persons using this document should be familiar with normal laboratory practice. This document does not purport to address all of the safety problems, if any, associated with its use.
30、 It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions.WARNING 2 Certain procedures specified in this document might involve the use or generation of substances or the generation of waste, that could
31、 constitute a local environmental hazard. Reference should be made to appropriate documentation on safe handling and disposal after use.1 ScopeThis document specifies a method for the determination of the resistance of vulcanized rubbers to fatigue under repeated tensile deformations, the test piece
32、 size and frequency of cycling being such that there is little or no temperature rise. Under these conditions, failure results from the growth 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
33、 of each cycle. Analogous fatigue processes can occur under repeated deformations which do not pass through zero strain and also, in certain 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
34、stable stress-strain properties, at least after a period of cycling, and that do not show undue stress softening or set, or highly viscous behaviour. Materials that do not meet these criteria might present considerable difficulties from the points of view of both experiment and interpretation. For e
35、xample, for a rubber that develops a large amount of set during the fatigue test, the test strain will be ill-defined and the fatigue life 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 co
36、mpared with those for other rubbers, has not been established by basic work. As a general guide, a rubber for which the set determined 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 elas
37、tomers.Similar considerations apply with regard to other changes in elasticity behaviour during testing.This fatigue test is distinct from the flexometer tests described in the various parts of ISO 4666, where fatigue breakdown occurs under the simultaneous action of stress and temperature.Advantage
38、s over the De Mattia flex cracking and cut growth test (see ISO 132) include the following: the test yields quantitative results which 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 differ
39、ent applications.Great caution is necessary in attempting to relate standard test results to service performance since the comparative 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 selec
40、tion of test conditions and on the interpretation of results is given in Annex A.2 Normative referencesThe following documents are 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.
41、For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 2017 All rights reserved 1BS ISO 6943:2017ISO 6943:2017(E)ISO 18899:2013, Rubber Guide to the calibration of test equipmentISO 23529, Rubber General procedures for preparing and conditioning
42、 test pieces for physical test methods3 Terms and definitionsFor the purposes of this document, the following terms and 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 .
43、org/ ISO Online browsing platform: available at h t t p :/ www .iso .org/ obp3.1fatigue lifenumber of cycles required to break a test piece repeatedly deformed to a prescribed tensile strain3.2tension fatiguefracture, through crack growth, of a component or test piece subjected to a repeated tensile
44、 deformation4 PrincipleDumb-bell or ring test pieces are repeatedly deformed in simple extension until they fail 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 th
45、e maximum strain and, if required, as a function of the maximum stress or strain energy density imposed during the test.5 Apparatus5.1 Fatigue-testing machineThe fatigue-testing machine shall provide a reciprocating motion at a frequency which shall normally be within the range 1 Hz to 5 Hz.For test
46、ing dumb-bell test pieces, the machine shall be provided with clamps that grip the test piece sufficiently 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 f
47、ixed to the body of the machine and the other to the reciprocating part. To minimize friction, the rollers 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 i
48、n place over the rollers throughout the test.The stroke of the machine and the position of the fixed clamps 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 prefer
49、ably 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 test conditions can be determined for rings if automatic equipment for force-extension measurement is provided.Alternatively, and for dumb-bell test pieces, stress-strain properties can be determined separat
