1、BRITISH STANDARD BS EN 60068-3-8:2003 Environmental testing Part 3-8: Supporting documentation and guidance Selecting amongst vibration tests The European Standard EN 60068-3-8:2003 has the status of a British Standard ICS 19.040; 29.020 BS EN 60068-3-8:2003 This British Standard was published under
2、 the authority of the Standards Policy and Strategy Committee on 4 February 2004 BSI 4 February 2004 ISBN 0 580 43362 5 National foreword This British Standard is the official English language version of EN 60068-3-8:2003. It is identical with IEC 60068-3-8:2003. The UK participation in its preparat
3、ion was entrusted to Technical Committee GEL/104, Environmental testing, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications r
4、eferred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary pr
5、ovisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretati
6、on, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 23 and a back cover. The BSI copyright
7、notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD EN 60068-3-8 NORME EUROPENNE EUROPISCHE NORM November 2003 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Norma
8、lisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 60068-3-8:2003 E ICS 19.040; 29.020 English
9、 version Environmental testing Part 3-8: Supporting documentation and guidance Selecting amongst vibration tests (IEC 60068-3-8:2003) Essais denvironnement Partie 3-8: Documentation daccompagnement et lignes directrices - Slection dessais de vibrations (CEI 60068-3-8:2003) Umweltprfungen Teil 3-8: U
10、ntersttzende Dokumentation und Leitfaden Auswahl zwischen verschiedenen Schwingprfverfahren (IEC 60068-3-8:2003) This European Standard was approved by CENELEC on 2003-11-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
11、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 Central Secretariat or to any CENELEC member. This European Standard exists in three official versions
12、(English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Aust
13、ria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Lithuania, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom. Foreword The text of document 104/308/FDIS, future edition 1 of IEC 60068-3
14、-8, prepared by IEC TC 104, Environmental conditions, classification and methods of test, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60068-3-8 on 2003-11-01. The following dates were fixed: latest date by which the EN has to be implemented at national level by p
15、ublication of an identical national standard or by endorsement (dop) 2004-08-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2006-11-01 Annexes designated “normative“ are part of the body of the standard. In this standard, annex ZA is normative. Anne
16、x ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 60068-3-8:2003 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following note has to be added for the standard indicated: IEC 60721-
17、3-0 NOTE Harmonized as HD 478.3.0 S1:1987 (not modified). _ Page2 EN6006838:200360068-3-8 IEC:2003 3 CONTENTS INTRODUCTION.4 1 Scope.5 2 Normative references.5 3 Terms and definitions .6 4 Description of vibration test methods7 4.1 General.7 4.2 Test methods7 4.3 Accelerated testing9 5 Vibration env
18、ironment of a specimen9 5.1 General.9 5.2 Collecting information, preparing a decision 9 5.3 Definition of dynamic conditions 10 6 Estimation of real life dynamic conditions for the specimen.10 6.1 General.10 6.2 Measurement of dynamic conditions10 6.3 Data analysis11 7 Selection of test method.15 7
19、.1 General.15 7.2 Sine testing.16 7.3 Random testing.16 7.4 Mixed mode testing .17 8 Vibration response investigation of the specimen .17 8.1 General.17 8.2 Aims, purposes.18 8.3 Sinusoidal excitation.18 8.4 Random excitation.19 8.5 Problem investigation (troubleshooting).19 8.6 Survival pass/fail c
20、riterion .19 8.7 Information to be given in the relevant specification 21 Annex ZA (normative) Normative references to international publications with their corresponding European publications .22 Bibliography23 Figure 1 Probability density of a single frequency sinusoidal signal13 Figure 2 Probabil
21、ity density of a mixture of sine and random signals13 Figure 3 Autocorrelation functions for various signals 14 Table 1 Examples of vibration environment and recommended test method.15 Table 2 Recommended method for response investigation.21 Page3 EN6006838:200360068-3-8 IEC:2003 4 INTRODUCTION Comp
22、onents, equipment and other electrotechnical products, hereinafter called specimens, can be subjected to different kinds of vibration during manufacture, transportation or in service. In the IEC 60721-3 standards, those different vibration environments are tabulated into classes characterizing stati
23、onary and transient vibration conditions. The standards in the IEC 60068-2 series describe methods for testing with stationary or transient vibration. There will be three standards in the IEC 60068-2 series for environmental testing that specify test methods employing stationary vibration: Part 2-6
24、Test Fc: Vibration (sinusoidal), Part 2-64 Test Fh: Vibration, broad-band random (digital control) and guidance, and Part 2-80 Test F-: Mixed mode testing 1_ 1Under consideration. Page4 EN6006838:200360068-3-8 IEC:2003 5 ENVIRONMENTAL TESTING Part 3-8: Supporting documentation and guidance Selecting
25、 amongst vibration tests 1 Scope This part of IEC 60068 provides guidance for selecting amongst the IEC 60068-2 stationary vibration test methods Fc sinusoidal, Fh random and F(x) Mixed mode vibration. The different steady-state test methods and their aims are briefly described in Clause 4. Transien
26、t test methods are not included. For vibration testing, the environmental conditions, especially the dynamic conditions for the specimen, should be known. This standard helps to collect information about the environmental conditions (Clause 5), to estimate or measure the dynamic conditions (Clause 6
27、) and gives examples to enable decisions to be made on the most applicable environmental vibration test method. Starting from the condition, the method of selecting the appropriate test is given. Since real life vibration conditions are dominated by vibration of a random nature, random testing shoul
28、d be the commonly used method, see Table 1, Clause 7. The methods included hereafter may be used to examine the vibration response of a specimen under test before, during and after vibration testing. The selection for the appropriate excitation method is described in Clause 8 and tabulated in Table
29、2. In this standard specification, writers will find information concerning vibration test methods and guidance for their selection. For guidance on test parameters, or severities of one of the test methods, reference should be made to the normative references. 2 Normative references The following r
30、eferenced 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. IEC 60068-1, Environmental testing Part 1: General and guidance
31、IEC 60068-2-6, Environmental testing Part 2-6: Tests Test Fc: Vibration (sinusoidal) IEC 60068-2-64, Environmental testing Part 2-64: Test methods Test Fh: Vibration, broad- band random (digital control) and guidance IEC 60068-2-80, Environmental testing Part 2-80: Tests Test F-: Mixed mode testing
32、2IEC 60721-3 (all parts), Classification of environmental conditions Part 3: Classification of groups of environmental parameters and their severities IEC 60721-4 (all parts), Classification of environmental conditions Part 4: Guidance for the correlation and transformation of environmental conditio
33、n classes of IEC 60721-3 to the environmental tests of IEC 60068-2 _ 2Under consideration. Page5 EN6006838:200360068-3-8 IEC:2003 6 IEC Guide 104:1997, The preparation of safety publications and the use of basic safety publications and group safety publications ISO 2041, Vibration and shock Vocabula
34、ry ISO 5348, Mechanical vibration and shock Mechanical mounting of accelerometers 3 Terms and definitions For the purposes of this document, terms and definitions used are generally defined in ISO 2041, in IEC 60068-1, IEC 60068-2-6 or IEC 60068-2-64. Where, for the convenience of the reader, a defi
35、nition from one of those sources is included here, the derivation is indicated and departures from the definitions in those sources are also indicated. 3.1 dynamic conditions all parameters that describe the vibration environment for a specimen 3.2 stationary vibration type of vibration with all the
36、 vibration-related parameters (statistical and spectral) constant over time 3.3 frequency sweep change of exciting frequency during sine testing NOTE For further definitions for sine testing, see IEC 60068-2-6. 3.4 linear spectrum type of spectrum used for periodic signals, usually calculated with f
37、ast Fourier transformation (FFT) algorithms, units being, for example, m/s s or g/Hz or g s. IES-RP-DET 012.1 3.5 acceleration spectral density ASD type of spectrum used for stationary random signals, usually calculated using squared discrete Fourier transformations (DFT): mean-square value of that
38、part of an acceleration signal passed by a narrow-band filter of a centre frequency, per unit bandwidth, in the limit as the bandwidth approaches zero and the averaging time approaches infinity, sometimes called autospectrum, the unit being (m/s 2 ) 2 /Hz or g n2 /Hz ISO 2041, modified 3.6 autocorre
39、lation statistical measure of the degree of which one part of a signal is related to another part (offset by a given time) of the same signal NOTE The Fourier transform of the autocorrelation function gives the autospectrum or ASD, the unit being a ratio from 1 to +1. Page6 EN6006838:200360068-3-8 I
40、EC:2003 7 3.7 statistical degrees of freedom DOF for the estimation of the acceleration spectral density of random data with a time-averaging technique, effective number of statistical degrees of freedom derived from the frequency resolution and the effective averaging time IEC 60068-2-64, 4.3.5, IS
41、O 2041, modified 3.8 critical frequency frequencies at which malfunctioning and/or deterioration of performance of the specimen, which are dependent on vibration are exhibited, and/or mechanical resonances and/or other response effects occur, for example chatter 4 Description of vibration test metho
42、ds 4.1 General Environmental testing is used to simulate in a laboratory the effects of a real life vibration environment. Vibration testing uses different input signals to excite the specimen, for example on a vibration table. The test methods are characterized by those input signals. 4.2 Test meth
43、ods Sine and random vibration are different physical processes and produce different effects on the specimen. The specification writer should be aware that, due to the physically different processes there is no precise equivalence between sine and random vibration testing. It is strongly recommended
44、 not to attempt to transfer severities from sine to random or vice versa. A brief description of the various vibration test methods is given. 4.2.1 Sine testing Sine testing (IEC 60068-2-6) uses a sinusoidal signal with constant or changing frequency and amplitude. Only one frequency is applied at a
45、ny instant in time. The test conditions include frequency range (bands) or fixed frequencies, vibration amplitudes and test duration. Sinusoidal vibration rarely, if ever, occurs as a single frequency vibration in isolation in a real life environment. This can be the case even when measuring the acc
46、eleration directly on rotating machinery. Practical tolerances and clearances, e.g. in gears and bearings, generally result in a small change in frequency. Some form of random vibration is also produced by random properties of the rotating machinery. Sinusoidal vibration may be described as determin
47、istic. It follows an established pattern so that the value of the vibration at any designated future time is completely predictable from the past history. Page7 EN6006838:200360068-3-8 IEC:2003 8 An area where this type of testing can be advantageous is in the timing of a failure during a frequency
48、sweep, where it may be possible to associate it with a particular frequency that, otherwise, may not be readily obvious if applying a random test. However, compared to random vibration, it tends to take longer to produce failures because it excites each resonance only briefly during a sweep. Althoug
49、h only one frequency is applied at any one instant, it does allow a particular resonance of the specimen to potentially build to its full amplitude, if the sweep-rate is low enough. It can also be used for establishing possible damaging resonances particularly during design/development testing. An additional use of sinusoidal vibration
