1、raising standards worldwide NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BSI Standards Publication Rubber, vulcanized Determination of creep in compression or shear BS ISO 8013:2012National foreword This British Standard is the UK implementation of ISO 8013:2012. It superse
2、des BS ISO 8013:2006 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee PRI/22, Physical testing 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 al
3、l the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012 Published by BSI Standards Limited 2012 ISBN 978 0 580 69689 3 ICS 83.060 Compliance with a British Standard cannot confer immunity from legal obligations. This British
4、 Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2012. Amendments issued since publication Amd. No. Date Text affected BRITISH STANDARD BS ISO 8013:2012 ISO 2012 Rubber, vulcanized Determination of creep in compression or shear Caoutchouc vulc
5、anis Dtermination du fluage en compression ou en cisaillement INTERNATIONAL STANDARD ISO 8013 Third edition 2012-10-01 Reference number ISO 8013:2012(E) BS ISO 8013:2012 ISO 8013:2012(E) ii ISO 2012 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2012 All rights reserved. Unless otherwise speci
6、fied, 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 the requester. ISO copyright office Ca
7、se 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 BS ISO 8013:2012 ISO 8013:2012(E) ISO 2012 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope 1 2 Normative references . 1 3 T erms and
8、definitions . 1 4 Apparatus 2 4.1 Thickness-measuring device . 2 4.2 Compression device for measurement in compression . 2 4.3 Shear device for measurements in shear . 2 4.4 Temperature-controlled chamber 3 4.5 Timer . 3 5 Calibration . 7 6 Test piece . 7 6.1 Test piece for measurements in compressi
9、on 7 6.2 Test piece for measurements in shear 7 6.3 Number . 7 7 Time-lapse between vulcanization and testing . 8 8 Mechanical conditioning . 9 9 Test temperature 9 10 Procedure 9 10.1 Testing 9 10.2 Duration of test 10 11 Calculation of results .10 11.1 Creep increment 10 11.2 Creep index . 11 11.3
10、 Compliance increment . 11 12 Expression of results .12 13 Test report .12 Annex A (informative) Values of forces required for rubbers of different hardnesses 14 Annex B (normative) Calibration schedule15 Bibliography .18 BS ISO 8013:2012 ISO 8013:2012(E) Foreword ISO (the International Organization
11、 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 interested in a subject for which a technical committee has been established has
12、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 Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Intern
13、ational Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publicati
14、on as an International Standard requires approval by at least 75 % of the member bodies casting a vote. 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 right
15、s. ISO 8013 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 2, Testing and analysis. This third edition cancels and replaces the second edition (ISO 8013:2006), which has been revised to include a calibration schedule for the apparatus used (see Annex B). I
16、n addition, the maximum thickness of test pieces for measurement in shear (see 6.2) has been increased from 12 mm to 13 mm. iv ISO 2012 All rights reserved BS ISO 8013:2012 ISO 8013:2012(E) Introduction When a constant stress is applied to rubber, the deformation is not constant but increases gradua
17、lly with time; this behaviour is called “creep”. Conversely, when rubber is subjected to a constant strain, a decrease in the stress in the material takes place; this behaviour is called “stress relaxation”. The creep test is of particular interest where vulcanized rubbers are used to support a cons
18、tant load, such as in bearings or mountings. The processes responsible for creep can be physical or chemical in nature, and under all normal conditions both processes will occur simultaneously. However, at normal or low temperatures and/or short times, creep is dominated by physical processes, whils
19、t at high temperatures and/or long times, chemical processes are dominant. In general, physical creep is found to be directly proportional to logarithmic time, and chemical creep to linear time; but great care has to be taken in extrapolating time/creep curves in order to predict creep after periods
20、 considerably longer than those covered by the test, and in using tests at higher temperatures as accelerated tests to give information on creep at lower temperatures. In addition to the need to specify the temperature intervals and time intervals in a creep test, it is also necessary to specify the
21、 initial strain and the previous mechanical history of the test piece, since these might also influence the measured creep, particularly in rubbers containing filler. ISO 2012 All rights reserved v BS ISO 8013:2012 Rubber, vulcanized Determination of creep in compression or shear WARNING Persons usi
22、ng this International Standard should be familiar with normal laboratory practice. This standard 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
23、 with any national regulatory conditions. 1 Scope This International Standard specifies a method for the determination of creep in vulcanized rubber continuously subjected to compressive or to shear forces. The standard cannot be used for intermittent deformation of rubber. 2 Normative references Th
24、e 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) applies. ISO 1827, Rubber, vulcanized or thermoplastic Deter
25、mination of shear modulus and adhesion to rigid plates Quadruple shear methods ISO 4664-1, Rubber, vulcanized or thermoplastic Determination of dynamic properties Part 1: General guidance ISO 18899:2004, Rubber Guide to the calibration of test equipment ISO 23529, Rubber General procedures for prepa
26、ring and conditioning test pieces for physical test methods 3 T erms and definitio ns For the purposes of this document, the following terms and definitions apply. 3.1 creep increment increase in strain which occurs in a specified time interval under constant force and at constant temperature NOTE I
27、t is expressed as the ratio of the increase in deformation over the time interval to the initial, unstrained thickness. 3.2 creep index relative increase in strain which occurs in a specified time interval under constant force and at constant temperature NOTE It is expressed as the ratio of the incr
28、ease in the strain over the time interval to the strain at the beginning of the interval. 3.3 compliance increment ratio of the increase in strain which occurs in a specified time interval under constant force and at constant temperature to the constant stress applied INTERNATIONAL STANDARD ISO 8013
29、:2012(E) ISO 2012 All rights reserved 1 BS ISO 8013:2012 ISO 8013:2012(E) 4 Apparatus 4.1 Thickness-measuring device Thickness measurements shall be made using a device complying with either ISO 23529 or the test apparatus described in 4.2. lt shall be capable of measuring the test piece thickness t
30、o the nearest 0,1 mm. lt shall have plates of diameter at least 30 mm. The dial gauge shall be fitted with a flat contact perpendicular to the plunger and parallel to the base plate and shall operate with a foot pressure of (22 5) kPa. 4.2 Compression device for measurement in compression The appara
31、tus shall consist of two parallel, flat steel plates, between which the prepared test piece is compressed. In the case of unbonded test pieces, the plates shall be highly polished with a surface finished to not worse than 0,2 m arithmetic mean deviation from the mean line of the profile. It is recom
32、mended that the operating surfaces of the plates be lubricated. The plates shall be sufficiently rigid to withstand the force without bending and of sufficient size to ensure that the whole of the compressed test piece is within the area of the plates. NOTE For most purposes, a silicone or fluorosil
33、icone liquid having a kinematic viscosity of 0,01 m 2 /s at standard laboratory temperature is a suitable lubricant. One of the plates shall be rigidly mounted so that it does not move in any direction under the action of the compressive force. The other plate shall be able to move in a friction-fre
34、e manner in one direction only, i.e. in a direction coincident with the axis of the test piece (see Figures 1 and 2). The apparatus shall be capable of applying the full force with negligible overshoot and maintaining it constant to within 0,1 %. The mechanism for applying the force shall be such th
35、at the line of action of the applied force remains coincident with the axis of the test piece as it creeps. Suitable equipment shall be connected to the compression device so that the deformation of the test piece can be determined, to an accuracy of 0,1 % of the initial test piece thickness, at dif
36、ferent times after the force has been fully applied. Many types of apparatus have been used, with mechanical, electronic or optical measurement of deformation. Figure 2 shows a typical example using a micrometer dial gauge for the determination of creep in compression. The measuring device shall not
37、 exert a pressure of more than 22 kPa on the test piece before the test load is applied. If the tests are carried out at an elevated temperature, the test piece and the flat plates of the compression device shall be inside a temperature-controlled chamber (see 4.4). 4.3 Shear device for measurements
38、 in shear The apparatus shall be capable of measuring the shear deflection in the test piece due to the application of a constant shear force. The apparatus shall be capable of applying the full force with negligible overshoot and maintaining it constant to within 0,1 %. The force shall be applied e
39、ither to the central metal plate, with the outer plates rigidly mounted, or to the outer metal plates with the central plate rigidly mounted. The line of action of the applied force shall be in the plane of the central plate, and pass through its centre in a direction perpendicular to the undeformed
40、 rubber test pieces. This line of action shall be maintained as the test piece creeps (see Figure 3). The movement of the central plate relative to the outer plates shall be in a friction-free manner and only in the direction of the line of action of the applied force. Suitable equipment shall be co
41、nnected to the test piece so that relative movement of the central plate with respect to the outside plates can be determined with an accuracy of 0,01 mm at different times after the force has been fully applied. 2 ISO 2012 All rights reserved BS ISO 8013:2012 ISO 8013:2012(E) Key 1 steel plates 2 t
42、est piece 3 line of action of compressive force 0initial thickness Figure 1 Test piece in compression If the tests are carried out at an elevated temperature, the test piece and the flat plates to which it is bonded shall be inside a temperature-controlled chamber (see 4.4). Figure 4 shows a typical
43、 shear test fixture. 4.4 Temperature-controlled chamber If the tests are to be carried out at an elevated temperature, a test chamber shall be used, constructed in accordance with ISO 23529, and provided with temperature control to maintain the specified air temperature within the tolerances given i
44、n Clause 9. Satisfactory circulation of the air shall be achieved by means of a fan. Care shall be taken to minimize change in temperature of the test piece by conduction through metal parts which are connected with the outside of the chamber or by direct radiation from heaters within the chamber. 4
45、.5 Timer Use a timer reading in seconds and minutes. ISO 2012 All rights reserved 3 BS ISO 8013:2012 ISO 8013:2012(E) Key 1 dial gauge 2 locking lever 3 setting ring 4 temperature-controlled chamber 5 test piece 6 ceramic bar Figure 2 Example of test arrangement for creep in compression with tempera
46、ture-controlled chamber 4 ISO 2012 All rights reserved BS ISO 8013:2012 ISO 8013:2012(E) Key 1 steel plates 2 bonded test pieces 3 line of action of shear force 0initial thickness Figure 3 Test piece in shear ISO 2012 All rights reserved 5 BS ISO 8013:2012 ISO 8013:2012(E) Key 1 actuator 2 load cell
47、 aShall be in test chamber. F i g u r e 4 T y p i c a l t e s t fi x t u r e f o r d o u b l e - s h e a r t e s t p i e c e 6 ISO 2012 All rights reserved BS ISO 8013:2012 ISO 8013:2012(E) 5 Calibration The test apparatus shall be calibrated in accordance with the schedule given in Annex B. 6 Test
48、piece 6.1 Test piece for measurements in compression 6.1.1 The test piece shall be a cylindrical disc; two sizes may be used having the following dimensions: Type A shall have a diameter of (29,0 0,5) mm and a thickness of (12,5 0,5) mm. Type B shall have a diameter of (13,0 0,5) mm and a thickness
49、of (6,3 0,3) mm. NOTE These sizes correspond to type A and B test pieces in ISO 815-1 1 . 6.1.2 The test pieces shall be prepared in accordance with ISO 23529 by either moulding or cutting. They shall be free from any fabric or other reinforcing support. Cutting shall be carried out by means of a sharp rotating circular die or revolving knife, lubricated with soapy water, and brought carefully into contact with the rubber. Alternatively, the die or knife may be kept stationary an
