IEC_60068_2_27_2008

【实例简介】
环境测试 冲击 shock IEC_60068_2_27_2008
60068-2-27|C:2008 Figure B5- Spectrum of a final-peak saw-tooth 300 m/s2, 18 ms pulse compared with the spectra of 200 m/s half-sine pulses with durations between 3 ms and 20 ms 35 Table 1- Severities for shock testing Table A 1-Examples of pulse shapes and test severities typically employed for various applications 23 Table A.2-EXamples of severities typically employed for various applications 24 60068-2-27◎|EC:2008 INTERNATIONAL ELECTROTECHNICAL COMMISSION ENVIRONMENTAL TESTING Part 2-27: Tests- Test Ea and guidance: Shock F○ REWORD 1)The International Electrotechnical Commission (EC)is a worldwide organization for standardization comprising all national electrotechnical committees (EC National Committees). The object of iec is to promote international co-operation on all questions concerning standardization in the electrical and electronic tields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications echnical Reports, Publicly Available specifications (PAs)and Guides (hereafter referred to as"IEC Publication(s)). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non governmental organizations liaising with the ieC also participate in this preparation. IEC collaborates closely with the International Organization for standardization (Iso)in accordance with conditions determined by agreement between the two organizations 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees 3)IEC Publications have the form of recommendations for international use and are accepted by lEc National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of ec Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user n)In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in 5)EC provides na marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an EC Publication 6 All uscrs should cnsurc that they havc the latest edition of this publication 7)No liability shall attach to lEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees )and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications indispensable for the correct application of this publicalion publication. Use of the referenced publications is 8)Attention is drawn to the Normative references cited in th 9)Attention is drawn to the possibility that some of the elements of this iec Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights International Standard IEC 60068-2-27 has been prepared by iec technical committee 104 Environmenta conditions classification and methods of test This fourth edition cancels and replaces the third edition, published in 1987, and includes the merging of lEC 60068-2-29, second edition(1987). It constitutes a technical revision The major changes with regard to the previous edition concern the merging of lec 60068-2-29 into this edition of lEc 60068-2-27, Part 2-29 will be withdrawn as soon as this edition is published the introduction of soft packaged specimens as defined in the IEc ad hoc working group document agreed in Stockholm: 2000 60068-2270|C:2008 The text of this standard is based on the following documents FDIS Report on voting 1044FD8[10457R710 Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table This publication has been drafted in accordance with the ISo/EC Directives, Part 2 It has the status of a basic safety publication in accordance with IEC Guide 104 This standard is to be used in conjunction with IEC 60068-1 a list of all the parts in the iec 60068 series, under the general title environmental testing, can be found on the ec website The committee has decided that the contents of this publication will remain unchanged until the maintenanceresultdateindicatedontheiecwebsiteunderhttp:/webstore.iec.chinthedata related to the specific publication At this date, the publication will be a reconfirmed a withdrawn replaced by a revised edition, or amended 60068-2-27@|C:2008 INTRODUCTION This part of IEC 60068 deals with components, equipments and other electrotechnical products, hereinafter referred to as specimens", which, during transportation, storage and handling, or in use, may be subjected either to conditions involving relatively infrequent non repetitive or repetitive shocks. The shock test may also be used as a means of establishing the satisfactory design of a specimen in so far as its structural integrity is concerned and as a means of quality control. It consists of subjecting a specimen either to non-repetiti epetitive shocks of standard pulse shapes with specified peak acceleration and duralon ve or Specification writers will find a list of details to be considered for inclusion in specifications in Clause 11. The necessary guidance is given in Annex A 60068-2-27@|EC:2008 7 ENVIRONMENTAL TESTING Part 2-27: Tests- Test Ea and guidance: Shock Scope This part of lEc 60068 provides a standard procedure for determining the ability of a specimen to withstand specified severities of non-repetitive or repetitive shocks The purpose of this test is to reveal mechanical weakness and/or degradation in specified performances, or accumulated damage or degradation caused by shocks. In conjunction with the relevant specification, this may be used in some cases to determine the structural integrity of specimens or as a means of quality control (see Clause A. 2) This test is primarily intended for unpackaged specimens and for items in their transport case when the latter may be considered to be part of the specimen. If an item is to be tested unpackaged, it is referred to as a test specimen. However, if the item is packaged, then the item itself is referred to as a product and the item and its packaging together are referred to as a test specimen When used in conjunction with lEC 60068-2-47, this standard may be used for testing packaged products. This possibility was included in the 2005 version of lEC 60068-2-47 for the first time This standard is written in terms of prescribed pulse shapes. Guidance for the selection and application of these pulses is given in Annex a and the characteristics of the different pulse shapes are discussed in Annex B Wherever possible, the test severity and the shape of the shock pulse applied to the specimen should be such as to reproduce the effects of the actual transport or operational environment to which the specimen will be subjected, or to satisfy the design requirements if the object of the test is to assess structural integrity(see Clauses A 2 and A. 4) or the purposes of this test, the specimen is always mounted to the fixture or the table of the shock testing machine during testing NOTE The term shock testing machine is used throughout this standard, but other means of applying pulse shapes are not excluded. One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications 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 latest edition of the referenced document (including any amendments ) applies lEC 60068-1, Environmental testing- Part 1: General and guidance lEC 60068-2-47: 2005, Environmental testing- Part 2-47: Tests -Mounting of specimens for vibration, impact and similar dynamic tests IEC 60068-2-55, Environmental testing- Part 2-55: Tests-Test Ee and guidance: Bounce 60068-227cEc2008 IEC 60721-3-1, Classification of environmental conditions- Part 3: Classification of groups of environmental parameters and their severities- Section 1: Storage lEC 60721-3-5, Classification of environmental conditions-Part 3: Classification of groups of environ menta! parameters and their severities- Section 5: Ground vehicle installations Guide 104, The preparation of safety publications and the use of basic safety publications and group safety publications 3 Terms and definitions For the purposes of this document, the following terms anc definitions apply NOTE The terms used are, for the most part, defined in ISo 2041[11 or IEC 60068-1. The following additional terms anc definitions are also applicable for the purposes of this standard check point point located on the fixture, on the table surface of the shock-testing machine or on the specimen as close as possible to the fixing point, and in any case rigidly connected to it NoTE 1 A number of check points are used as a means of ensuring that the test requirements are satisfied NO E 2 If more than four fixing points exist, the relevant specification should state the number of fixing points to be used as check points. nOtE 3 In special cases, for example, for large or complex specimens, the check points will e prescribed by the relevant specification if not close to the fixing points NoTE 4 Where a large number of small specimens are mounted on one fixture, or in the case of a small specimen where there are a number of fixing points, a sing le check point(that is the reference point)may be selected for the derivation of the control signal. This sig nal is then related to the fixture rather than to the fixing points of the specimen(s). This procedure is only valid when the lowest resonance frequency of the loaded fixture is well above the upper frequen cy of the test fixing point part of the specimen in contact with the fixture or the table of the shock-testing machine at a point where the specimen is normally fastened in service NOTE If a part of the real mounting structure is used as the fixture, the fixing points are taken as those of tne mounting structure and not of the specimen 3.3 standard acceleration due to the earth's gravity which itself varies with altitude and geographical latitude Note For the purposes of this standard, the value of gn is rounded up to the nearest unity, that is 10 m/s2 repetition rate number of shocks per second 3.5 shock severity combination of the peak acceleration, the duration of the nominal pulse and the number of hocks Figures in square brackets refer to the bibliography 60068-2-273|EC:2008 3.6 velocity change absolute value oi the sudden change of velocity resulting from the application of the specified acceleration NOTE The change of velocity is normally considered sudden if if takes place in a time that is short compared with the fundamental period of the test specimen escription of test a pparatus 4.1 Required characteristics When the shock-testing machine with or without fixture is loaded with the specimen, the waveform measured at the check point(s) shall consist of a pulse approximating to one of the nominal acceleration against time curves given by the broken lines in Figures 1, 2 and 3. 4.1.1 Basic pulse shapes Three types of pulse, namely the half-sine pulse, the final-peak saw-tooth pulse and the trapezoidal pulse, are included in this standard. The choice of pulse shape depends on a number of factors, and the difficulties inherent in making such a choice preclude a preferred order being given in this standard (see clause A. 3) The specified basic pulse shapes are given below(see Clause A.3) half-sine: one half-cycle of a sine wave, as shown in Figure 1 final-peak saw-tooth: asymmetrical triangle with short fall time, as shown in Figure 2 trapezoidal: symmetrical trapezoid with short rise and fall times, as shown in Figure 3 he true value of the actual pulse shall be within the limits of tolerance shown by the solid lines in the relevant figure note Where it is not practicab le to achieve a pulse shape falling within the specified tolerance, the relevant specification should state the alternative procedure to be applied (see clause A. 5) 10 600682-27c|EC:2008 integration time 1,5D 12A A 08A 0,2A 0. 2A 0,2A 02A ,2A 04D 0.1D D 2.5D 2.5D 24D=71 GD=T Key(applicable for all three Figures 1 to 3) nominal pulse a= peak acce leration of nominal pulse limits of tolerance T1=minimum time during which the pulse shall be monitored for shocks produced using a conventional shock-testing machine d= duration of nominal pulse T2=minimum time during which the pulse shall be monitored for shocks produced using a vibration generator Figure 1-Pulse shape and limits of tolerance for half-sine pulse Integration time 1.5D 12 A 08A 0,2A 02A 0 0.2A 0,2A 04 0,1D 01D 2,5D 25D 24D=71 6D=T NEC 304/08 Figure 2-Pulse shape and limits of tolerance for final-peak saw-tooth pulse 【实例截图】
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