BS EN ISO 1798-2008 Flexible cellular polymeric materials - Determination of tensile strength and elongation at break《软质泡沫聚合材料 拉伸强度和断裂伸长率的测定》.pdf

1、BRITISH STANDARDBS EN ISO 1798:2008Flexible cellular polymeric materials Determination of tensile strength and elongation at breakICS 83.100g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60

2、g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 1798:2008This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 February 2008 BSI 2008ISBN 978 0 580 56893 0National forewordThis British Standard is the UK implementation of EN ISO 1798:2008. It

3、supersedes BS EN ISO 1798:2000 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee PRI/24, Testing of rigid and flexible cellular materials.A list of organizations represented on this committee can be obtained on request to its secretary.This publication d

4、oes not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments/corrigenda issued since publicationDate CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPIS

5、CHE NORMEN ISO 1798February 2008ICS 83.100 Supersedes EN ISO 1798:1999 English VersionFlexible cellular polymeric materials - Determination of tensilestrength and elongation at break (ISO 1798:2008)Matriaux polymres alvolaires souples - Dterminationde la rsistance la traction et de lallongement laru

6、pture (ISO 1798:2008)Weich-elastische polymere Schaumstoffe - Bestimmungder Zugfestigkeit und der Bruchdehnung (ISO 1798:2008)This European Standard was approved by CEN on 12 January 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giv

7、ing this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versi

8、ons (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bu

9、lgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDI

10、ZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 1798:2008: EForeword This document (EN ISO 1798:2008) h

11、as been prepared by Technical Committee ISO/TC 45 “Rubber and rubber products“ in collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by NBN. This European Standard shall be given the status of a national standard, either by publication of an identical text

12、or by endorsement, at the latest by August 2008, and conflicting national standards shall be withdrawn at the latest by August 2008. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible

13、for identifying any or all such patent rights. This document supersedes EN ISO 1798:1999. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republ

14、ic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 1798:2008 has been

15、 approved by CEN as a EN ISO 1798:2008 without any modification. BS EN ISO 1798:2008Reference numberISO 1798:2008(E)INTERNATIONAL STANDARD ISO1798Fourth edition2008-02-01Flexible cellular polymeric materials Determination of tensile strength and elongation at break Matriaux polymres alvolaires soupl

16、es Dtermination de la rsistance la traction et de lallongement la rupture BS EN ISO 1798:2008ii iiiContents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Apparatus 2 5 Test pieces 2 6 Procedure 4 7 Calculation. 4 8 Test report . 5 Annex A (informative) Comparat

17、ive testing of type 1 and type 1A test pieces . 6 Bibliography . 11 BS EN ISO 1798:2008iv 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 ou

18、t 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 work. ISO co

19、llaborates 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 technical committees is to prepare International

20、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 drawn to the possibility that some of the element

21、s 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 1798 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 4, Products (other than hoses). This fourth edition cancels and

22、 replaces the third edition (ISO 1798:1997), which has been technically revised. It also incorporates the Technical Corrigendum ISO 1798:1997/Cor.1:2003. The main change is the introduction of a second type of test piece (see Figure 1) and a comparison of the results obtained with the two test piece

23、s (see Annex A). BS EN ISO 1798:20081Flexible cellular polymeric materials Determination of tensile strength and elongation at break WARNING Persons using this International Standard should be familiar with normal laboratory practice. This standard does not purport to address all of the safety probl

24、ems, 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. 1 Scope This International Standard specifies a method for determining the strength and deformation proper

25、ties of flexible cellular materials when a test piece is extended at a constant rate until it breaks. 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 la

26、test edition of the referenced document (including any amendments) applies. ISO 1923, Cellular plastics and rubbers Determination of linear dimensions ISO 7500-1:2004, Metallic materials Verification of static uniaxial testing machines Part 1: Tension/compression testing machines Verification and ca

27、libration of the force-measuring system ISO 9513, Metallic materials Calibration of extensometers used in uniaxial testing ISO 23529, Rubber General procedures for preparing and conditioning test pieces for physical test methods 3 Terms and definitions For the purposes of this document, the followin

28、g terms and definitions apply. 3.1 tensile strength TS maximum tensile stress applied when stretching a test piece to rupture 3.2 elongation at break Ebpercentage elongation of a test piece at rupture BS EN ISO 1798:20082 4 Apparatus 4.1 Tensile-testing machine, complying with the following requirem

29、ents: the rate of travel of the power-actuated grip shall be 500 mm/min 50 mm/min and shall be uniform at all times; the accuracy of the machine shall conform to class 0,5 or class 1 of ISO 7500-1:2004 for force-measurement over the range of loading employed. For the determination of elongation at b

30、reak, the machine may be equipped with either a mechanical or an optical extensometer. If used, however, the extensometer shall comply with the following requirements which shall be verified in accordance with ISO 9513: initial gauge length accurate to 1 %; gauge length at break accurate to 1,25 mm.

31、 When a mechanical contact extensometer is used, care shall be taken that the contact elements do not damage the test piece. In addition, their mass and inertia shall not influence the determination of the maximum tensile strength by more than 1 %. 5 Test pieces 5.1 Direction of sampling If the prod

32、uct shows a predominant direction of the cellular structure (orientation of the cells), the test pieces for the tensile test shall be taken in such a way that their longitudinal axes lie at right angles to this predominant direction. If it is not possible, the location of the longitudinal axis with

33、respect to the predominant direction shall be stated in the test report. 5.2 Shape and dimensions The test pieces shall be rectangular in cross-section, with or without skin, and without visible defects. The test pieces shall be cut out with one of the two types of test piece cutter shown in Figure

34、1 and shall be 10 mm to 15 mm thick. 5.3 Number of test pieces Unless agreed otherwise between the interested parties, sufficient test pieces shall be tested to provide five breaks within the gauge length. BS EN ISO 1798:20083Dimensions in millimetres a) Type 1 b) Type 1A Figure 1 Test-piece cutters

35、 5.4 Conditioning 5.4.1 The test pieces or the material from which the test pieces are to be cut shall be prepared and conditioned in accordance with ISO 23529, unless otherwise specified. 5.4.2 Materials shall not be tested less than 72 h after manufacture, unless at either 16 h or 48 h after manuf

36、acture it can be demonstrated that the mean results do not differ by more than 10 % from those obtained after 72 h. Testing is permitted at either 16 h or 48 h if, at the specified time, the above criterion has been satisfied. Prior to the test, the test pieces or the material from which the test pi

37、eces are to be cut shall be conditioned for at least 16 h in one of the following atmospheres: 23 C 2 C, (50 5) % relative humidity; 27 C 2 C, (65 5) % relative humidity. This period can form the latter part of the period following manufacture. 5.4.3 In the case of quality-control tests, test pieces

38、 can be taken a shorter time (down to a minimum of 12 h) after manufacture and testing carried out after conditioning for a shorter period (down to a minimum of 6 h) in one of the atmospheres specified above. BS EN ISO 1798:20084 6 Procedure 6.1 After conditioning as specified in 5.4, measure the th

39、ickness of the material at five evenly distributed points in the area from which the test pieces are to be cut. These measurements shall be made in accordance with ISO 1923 and shall not vary from each other by more than 2 %. If desired, thickness measurements can be performed on cut test pieces, bu

40、t test pieces whose thickness falls outside these limits shall be rejected. 6.2 Mark the gauge length on each test piece with two reference lines, using a marker with two parallel marking edges. Measure the distance between the inside edges of the lines to an accuracy of 1 % (these lines shall be at

41、 least 25 mm and not more than 50 mm apart for type 1 test pieces and not more than 40 mm apart for type 1A test pieces). 6.3 Set the load-indicating device to zero and place a test piece in the grips of the tensile-testing machine (4.1), taking care to mount the test piece symmetrically so that the

42、 tension will be distributed uniformly over its cross-section. A preload stress of up to 0,1 kPa or a preload extension of up to 0,5 % may be applied. When using an extensometer, zero it on completion of the preload. Start the machine at a jaw-separation rate of 500 mm/min 50 mm/min and record the m

43、aximum force (measured to 1 %) and the distance between the inside edges of the two reference lines (measured to 1,25 mm) immediately prior to break of the test piece. Reject test pieces which break outside the gauge length, and continue testing until five satisfactory results are obtained. Sufficie

44、nt material will have to be available to ensure that retesting can be carried out. 6.4 Carry out the test at the same temperature and humidity as that used for conditioning the test material. NOTE In the case of the type 1 cutter, the probability of test pieces being rejected can be minimized by sel

45、ecting a gauge length close to the maximum permitted value of 50 mm. 7 Calculation 7.1 Tensile strength Calculate the average thickness of each test piece. Calculate the average initial cross-sectional area of each test piece on the basis of the average thickness and the width of the central section

46、 of the test piece cutter (13 mm for type 1 and 10 mm for type 1A). The tensile strength (TS) of each test piece, expressed in kilopascals, is given by the equation 3TS 10FA=where F is the maximum force, in newtons; A is the average initial cross-sectional area, in square millimetres. 7.2 Elongation

47、 at break The elongation at break, Eb, expressed as a percentage of the original gauge length, is given by the equation 0b0100LLEL=where L is the gauge length at break, in millimetres; L0is the initial gauge length, in millimetres. BS EN ISO 1798:200858 Test report The test report shall include the

48、following information: a) a reference to this International Standard; b) the nature of the cellular material; c) the type of test piece used; d) details of test piece conditioning; e) the location in the product from which the test pieces were taken, and the predominant direction of the cellular str

49、ucture, if any; f) the location and number of surfaces with skin, if any; g) the test piece thickness; h) the median value of the tensile strength, in kilopascals; i) the median value of the elongation at break, in percent; j) any deviations from this International Standard. BS EN ISO 1798:20086 Annex A (informative) Comparative testing of type 1 and type 1A test pieces A.1 General This annex gives a comparison of test results obtained with the new type 1A test piece and the old type 1 test