EN ISO 26203-1-2018 en Metallic materials - Tensile testing at high strain rates - Part 1 Elastic-bar-type systems.pdf

1、BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Metallic materials - Tensile testing at high strain ratesPart 1: Elastic-bar-type systemsBS EN ISO 26203-1:2018National forewordThis British Standard is the UK implementation of EN ISO 26203-1:2018. It is identical to I

2、SO 26203-1:2018. It supersedes BS EN ISO 26203-1:2010, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee ISE/101/1, Uniaxial testing.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does n

3、ot purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2018 Published by BSI Standards Limited 2018ISBN 978 0 580 96331 5ICS 77.040.10Compliance with a British Standard cannot confer immunity from legal o

4、bligations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2018.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN ISO 26203-1:2018EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 26203-1March

5、 2018ICS 77.040.10 Supersedes EN ISO 26203-1:2010EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGCEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2018 CEN Ref. No. EN ISO 26203-1:2018: EAll rights of exploitation in any form and by an

6、y means reserved worldwide for CEN national MembersMetallic materials - Tensile testing at high strain rates - Part 1: Elastic-bar-type systems (ISO 26203-1:2018)Matriaux mtalliques - Essai de traction vitesses de dformation leves - Partie 1: Systmes de type barre lastique (ISO 26203-1:2018)Metallis

7、che Werkstoffe - Zugversuch bei hohen Dehngeschwindigkeiten - Teil 1: Elastische Stowellentechnik (ISO 26203-1:2018)This European Standard was approved by CEN on 28 February 2018.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

8、European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.This European Standard exists in three official vers

9、ions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.CEN members are the national standards bodies of Austria,

10、Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sw

11、eden, Switzerland, Turkey and United Kingdom.English VersionEN ISO 26203-1:2018 (E)European forewordThis document (EN ISO 26203-1:2018) has been prepared by Technical Committee ISO/TC 164 “Mechanical testing of metals” in collaboration with Technical Committee ECISS/TC 101 “Test methods for steel (o

12、ther than chemical analysis)” the secretariat of which is held by AFNOR.This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September 2018, and conflicting national standards shall be withdrawn at the

13、 latest by September 2018.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights.This document supersedes EN ISO 26203-1:2010.According to the CEN-CENELEC In

14、ternal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland,

15、 Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.Endorsement noticeThe text of ISO 26203-1:2018 has been approved by CEN as EN ISO 26203-1:2018 without any modi

16、fication.2BS EN ISO 26203-1:2018ISO 26203-1:2018Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Principles . 15 Symbols and designations 26 Apparatus . 37 Test piece 57.1 Test-piece shape, size and preparation 57.2 Typical test piece . 78 Calibration of the a

17、pparatus 88.1 General . 88.2 Displacement measuring device 99 Procedure. 99.1 General . 99.2 Mounting the test piece . 99.3 Applying force 99.4 Measuring and recording . 910 Evaluation of the test result .1111 Test report 12Annex A (informative) Quasi-static tensile testing method .14Annex B (inform

18、ative) Example of one-bar method 16Annex C (informative) Example of split Hopkinson bar (SHB) method 23Bibliography .30 ISO 2018 All rights reserved iiiContents PageBS EN ISO 26203-1:2018ISO 26203-1:2018ForewordISO (the International Organization for Standardization) is a worldwide federation of nat

19、ional 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. Interna

20、tional 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

21、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.i

22、so.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 wil

23、l 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, the meaning

24、 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 prepared by Technical

25、Committee ISO/TC 164, Mechanical testing of metals, Subcommittee SC 1, Uniaxial testing.This second edition cancels and replaces the first edition (ISO 26203-1:2010), of which it constitutes a minor revision.The main changes compared to the previous edition are as follows: a note above 7.1 d) has be

26、en added.A list of all parts in the ISO 26203 series can be found on the ISO website.iv ISO 2018 All rights reservedBS EN ISO 26203-1:2018ISO 26203-1:2018IntroductionTensile testing of metallic sheet materials at high strain rates is important to achieve a reliable analysis of vehicle crashworthines

27、s. During a crash event, the maximum strain rate often reaches 103s1, at which the strength of the material can be significantly higher than that under quasi-static loading conditions. Thus, the reliability of crash simulation depends on the accuracy of the input data specifying the strain-rate sens

28、itivity of the materials.Although there are several methods for high-strain rate testing, solutions for three significant problems are required.The first problem is the noise in the force measurement signal. The test force is generally detected at a measurement point on the force measurement device

29、that is located some distance away from the test piece. Furthermore, the elastic wave which has already passed the measurement point returns there by reflection at the end of the force measurement device. If the testing time is comparable to the time for wave propagation through the force measuremen

30、t device, the stress-strain curve may have large oscillations as a result of the superposition of the direct and indirect waves. In quasi-static testing, contrarily, the testing time is sufficiently long to have multiple round-trips of the elastic wave. Thus, the force reaches a saturated state and

31、equilibrates at any point of the force measurement device. There are two opposing solutions for this problem. The first solution is to use a short force measurement device which will reach the saturated state quickly. This approach is often adopted in the servo-hydraulic type system. The second solu

32、tion is to use a very long force measurement device which allows the completion of a test before the reflected wave returns to the measurement point. The elastic-bar-type system is based on the latter approach.The second problem is the need for rapid and accurate measurements of displacement or test

33、 piece elongation. Conventional extensometers are unsuitable because of their large inertia. Non-contact type methods such as optical and laser devices should be adopted. It is also acceptable to measure displacements using the theory of elastic wave propagation in a suitably-designed apparatus, exa

34、mples of which are discussed in this document. The displacement of the bar end can be simply calculated from the same data as force measurement, i.e. the strain history at a known position on the bar. Thus, no assessment of machine stiffness is required in the elastic-bar-type system.The last proble

35、m is the inhomogeneous section force distributed along the test piece. In quasi-static testing, a test piece with a long parallel section and large fillets is recommended to achieve a homogeneous uniaxial-stress state in the gauge section. In order to achieve a valid test with force equilibrium duri

36、ng the dynamic test, the test piece is to be designed differently from the typically designed quasi-static test piece. Dynamic test pieces are intended to be generally smaller in the dimension parallel to the loading axis than the test pieces typically used for quasi-static testing.The elastic-bar-t

37、ype system can thus provide solutions for dynamic testing problems and is widely used to obtain accurate stress-strain curves at around 103s1. The International Iron and Steel Institute developed the “Recommendations for Dynamic Tensile Testing of Sheet Steel” based on the interlaboratory test condu

38、cted by various laboratories. The interlaboratory test results show the high data quality obtained by the elastic-bar-type system. The developed knowledge on the elastic-bar-type system is summarized in this document; ISO 26203-2 covers servo-hydraulic and other test systems used for high-strain-rat

39、e tensile testing. ISO 2018 All rights reserved vBS EN ISO 26203-1:2018This page deliberately left blankMetallic materials - Tensile testing at high strain rates Part 1: Elastic-bar-type systems1 ScopeThis document specifies methods for testing metallic sheet materials to determine the stress-strain

40、 characteristics at high strain rates. This document covers the use of elastic-bar-type systems.The strain-rate range between 103and 103s1is considered to be the most relevant to vehicle crash events based on experimental and numerical calculations such as the finite element analysis (FEA) work for

41、crashworthiness.In order to evaluate the crashworthiness of a vehicle with accuracy, reliable stress-strain characterization of metallic materials at strain rates higher than 103s1is essential.This test method covers the strain-rate range above 102s1.NOTE 1 At strain rates lower than 101s1, a quasi-

42、static tensile testing machine that is specified in ISO 7500-1 and ISO 6892-1 can be applied.NOTE 2 This testing method is also applicable to tensile test-piece geometries other than the flat test pieces considered here.2 Normative referencesThere are no normative references in this document.3 Terms

43、 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: ISO Online browsing platform: available at https:/www.iso.org/obp IEC Electropedia: available at http:/www

44、.electropedia.org/3.1elastic-bar-type systemmeasuring system in which the force-measuring device is lengthened in the axial direction to prevent force measurement from being affected by waves reflected from the ends of the apparatusNote 1 to entry: The designation “elastic-bar-type system” comes fro

45、m the fact that this type of system normally employs a long elastic bar as force-measuring device.4 PrinciplesThe stress-strain characteristics of metallic materials at high strain rates are evaluated.INTERNATIONAL STANDARD ISO 26203-1:2018 ISO 2018 All rights reserved 1BS EN ISO 26203-1:2018ISO 262

46、03-1:2018At a strain rate higher than 10 s1, the signal of the loading force is greatly perturbed by multiple passages of waves reflected within the load cell that is used in the quasi-static test. Thus, special techniques are required for force measurement. This may be accomplished in two opposite

47、ways: one is to lengthen the force measurement device in the loading direction, in order to finish the measurement before the elastic wave is reflected back from the other end (elastic-bar-type systems); another way is to shorten the force measurement device, thus reducing the time needed to attain

48、dynamic equilibrium within the force measurement device and realizing its higher natural frequency (servo-hydraulic type systems).Tests at low strain rates (under 101s1) can be carried out using a quasi-static tensile testing machine. However, special considerations are required when this machine is

49、 used for tests at strain rates higher than conventional ones. It is necessary to use a test piece specified for high-strain-rate testing methods. Annex A provides details of the test procedure for this practice.5 Symbols and designationsSymbols and their corresponding designations are given in Table 1.Table 1 Symbols and designationsSymbol Unit DesignationTest pieceaomm original thickness of a flat test piecebomm original width of the parallel length of a flat test piecebgmm width(s) of the grip section of a test pieceLomm orig