SIST EN 60068-2-64:2008

Environmental testing -- Part 2-64: Tests - Test Fh: Vibration, broadband random and guidance

IEC 60068-2-64:2008 demonstrates the adequacy of specimens to resist dynamic loads without unacceptable degradation of its functional and/or structural integrity when subjected to the specified random vibration test requirements. Broadband random vibration may be used to identify accumulated stress effects and the resulting mechanical weakness and degradation in the specified performance. This information, in conjunction with the relevant specification, may be used to assess the acceptability of specimens. This standard is applicable to specimens which may be subjected to vibration of a stochastic nature resulting from transportation or operational environments, for example in aircraft, space vehicles and land vehicles. It is primarily intended for unpackaged specimens, and for items in their transportation container when the latter may be considered as part of the specimen itself. 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. This standard may be used in conjunction with IEC 60068-2-47:2005, for testing packaged products. If the specimens are subjected to vibration of a combination of random and deterministic nature resulting from transportation or real life environments, for example in aircraft, space vehicles and for items in their transportation container, testing with pure random may not be sufficient. See IEC 60068-3-8:2003 for estimating the dynamic vibration environment of the specimen and based on that, selecting the appropriate test method. The major changes with regard to the previous edition concern the removal of Method 1 and Method 2, replaced by a single method, and replacement of Annex A with suggested test spectra and removal of Annex C. Also included in this revision is the testing of soft packed specimens. Has the status of a basic safety publication in accordance with IEC Guide 104.

Umgebungseinflüsse - Teil 2-64: Prüfverfahren - Prüfung Fh: Schwingen, Breitbandrauschen (digital geregelt) und Leitfaden

Essais d'environnement -- Partie 2-64: Essais - Essai Fh: Vibrations aléatoires à large bande et guide

La CEI 60068-2-64:2008 a pour objet de démontrer la capacité des spécimens à résister aux charges dynamiques sans dégradation inacceptable de leur intégrité de fonctionnement et/ou de structure, lorsqu'ils sont soumis à des exigences d'essais de vibrations aléatoires spécifiées. L'essai de vibration aléatoire à large bande peut être utilisé pour identifier les effets de contraintes accumulées ainsi que la faiblesse et la dégradation mécaniques résultantes de la performance spécifiée. Ces informations, conjointement avec la spécification particulière, peuvent être utilisées pour évaluer l'acceptabilité des spécimens. Cette norme est applicable à des spécimens qui peuvent être soumis à des vibrations de nature stochastique dues au transport ou à l'environnement rencontré en service, par exemple, à bord d'avions et de véhicules spatiaux ou à bord de véhicules terrestres. Elle est destinée en premier lieu à des spécimens non emballés et à des objets dans leur emballage de transport lorsque celui-ci peut être considéré comme faisant partie du spécimen lui-même. Cependant, si l'article est emballé alors l'article lui-même est désigné comme produit et l'article ainsi que son emballage sont désignés comme spécimen d'essai. Cette norme peut être utilisée conjointement avec la CEI 60068 2 47:2005, pour l'essai des produits emballés. Si les spécimens sont soumis à des vibrations d'une combinaison de nature aléatoire et déterministe résultant du transport ou des environnements de la vie réelle, par exemple à bord d'avions, de véhicules spatiaux et pour des éléments dans leur emballage de transport, les essais purement aléatoires peuvent ne pas être suffisants. Voir la CEI 60068-3-8:2003 pour l'estimation de l'environnement de vibrations dynamiques du spécimen et sur cette base, pour la sélection de la méthode d'essai appropriée. Les modifications principales par rapport à l'édition précédente concernent le retrait de la Méthode 1 et de la Méthode 2, remplacées par une méthode unique, et remplacement de l'Annexe A par des spectres d'essais préconisés et le retrait de l'Annexe C. Aussi inclus dans cette révision, l'essai des spécimens avec emballages mous. A le statut de publication fondamentale de sécurité, conformément au Guide CEI 104.

Okoljski preskusi - 2-64. del: Preskusi - Preskus Fh: Vibracije, naključne širokopasovne, in vodilo (IEC 60068-2-64:2008)

Ta del standarda IEC 60068 izkazuje primernost primerkov glede odpornosti proti dinamičnim obremenitvam brez nesprejemljivega poslabšanja funkcionalne in/ali strukturne celovitosti, kadar so izpostavljeni podanim naključnim zahtevam preskušanja vibracij. Naključne širokopasovne vibracije se lahko uporabijo za določanje nakopičenih učinkov obremenitve ter posledične mehanske šibkosti in poslabšanja podanih lastnosti. Te informacije se lahko skupaj z ustrezno specifikacijo uporabijo za vrednotenje sprejemljivosti primerkov. Ta standard se uporablja za primerke, ki so lahko izpostavljeni stohastičnim vibracijam zaradi transportnih ali obratovalnih okolij, na primer v letalih, vesoljskih plovilih in kopenskih vozilih. Prvotno je namenjen nezapakiranim primerkom in predmetom v njihovem transportnem vsebniku, pri čemer se slednji lahko obravnava kot del samega primerka. Kadar pa je predmet zapakiran, se sam predmet obravnava kot izdelek, izdelek in njegova embalaža pa se obravnavata kot preskušanec. Ta standard se lahko uporablja v povezavi s standardom IEC 60068-2-47:2005 za preskušanje zapakiranih izdelkov. Če so primerki izpostavljeni kombinaciji naključnih in določenih vibracij zaradi transportnih ali dejanskih življenjskih okolij (na primer v letalih, vesoljskih plovilih in za predmete v njihovem transportnem vsebniku), preskušanje zgolj z naključnimi morda ne bo zadostovalo. Glej standard IEC 60068-3-8:2003 za ocenjevanje okolja dinamičnih vibracij vzorca in (na podlagi tega) za izbiro ustrezne preskusne metode. Čeprav je prvotno namenjen elektrotehničnim primerkom, ta standard ni omejen nanje in se lahko poljubno uporablja na drugih področjih (glej dodatek A).

General Information

• Status: Published
• Publication Date: 07-Oct-2008
• ICS: 19.040 - Environmental testing
• Technical Committee: I09 - Imaginarni 09
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 24-Sep-2008
• Due Date: 29-Nov-2008
• Completion Date: 08-Oct-2008
• Directive: 2014/32/EU - Directive 2014/32/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of measuring instruments
• Ref Project: EN 60068-2-64:2008 - Environmental testing - Part 2-64: Tests - Test Fh: Vibration, broadband random and guidance

Relations

• Replaces: SIST EN 60068-2-64:2001 - Environmental testing -- Part 2: Test methods - Test Fh: Vibration, broad-band random (digital control) and guidance
• Effective Date: 01-Sep-2011
• Amended By: SIST EN 60068-2-64:2008/A1:2020 - Environmental testing - Part 2-64: Tests - Test Fh: Vibration, broadband random (digital contol) and guidance (IEC 60068-2-64:2008/A1:2019)
• Effective Date: 18-Oct-2016

Overview - EN 60068-2-64:2008 (Test Fh: Vibration, broadband random)

EN 60068-2-64:2008 (Test Fh) is the European adoption of IEC 60068-2-64 and defines procedures for broadband random vibration testing used in environmental testing and product qualification. The standard demonstrates whether specimens can resist stochastic vibration loads (transportation or operational) without unacceptable degradation of functional or structural integrity. It covers unpackaged items, items considered together with their transport container, and includes guidance for testing soft‑packed specimens.

Key topics and technical requirements

• Scope and purpose: Assess accumulated stress effects and mechanical degradation under broadband random vibration to determine specimen acceptability against a relevant specification.
• Test apparatus and control: Requirements for vibration generators (e.g., electrodynamic or servo‑hydraulic systems), digital control strategies, measuring systems and allowable vibration tolerances.
• Mounting and instrumentation: Guidance on specimen mounting (including packaged items), sensor placement and response monitoring; can be used with IEC 60068-2-47 for packaged products.
• Spectra and severities: Defines how to specify test frequency range, RMS acceleration, shape of acceleration spectral density (ASD) curves and test duration; Annex A provides suggested test spectra for various environments.
• Response investigation and equalization: Procedures for initial and final vibration response investigations, low‑level equalization prior to full testing, and verification of statistical accuracy.
• Preconditioning, recovery and reporting: Requirements for pre‑ and post‑test conditioning, functional performance checks, recovery periods and information to include in test reports.
• Statistical nature: Emphasis that random vibration testing is probabilistic; the standard provides guidance (Annex B) and expects engineering judgement when selecting severities and methods.

Applications and practical value

• Product qualification and reliability testing: Used to validate electronic/electromechanical components, assemblies and systems for transport and operational vibration environments.
• Industries: Aerospace, space, automotive, rail, defense and general transportation where stochastic vibration is significant.
• Use cases: Design verification, production qualification, comparative testing of design variants, and pre‑shipment validation of items and their packaging.
• Benefits: Identifies accumulated fatigue, mechanical weaknesses and potential functional degradation that deterministic tests may miss.

Who should use this standard

• Test engineers and vibration lab technicians
• Reliability and qualification engineers
• Product designers and test planners in aerospace, automotive and transport sectors
• Accredited test laboratories (ISO/IEC 17025)

Related standards

• IEC 60068-1 (General and guidance)
• IEC 60068-2-47 (Mounting of specimens for vibration tests)
• IEC 60068-3-8 (Estimating dynamic vibration environments)
• ISO/IEC 17025 (Laboratory competence)

Keywords: EN 60068-2-64, IEC 60068-2-64, vibration testing, broadband random, test Fh, environmental testing, random vibration, transport vibration, test spectra.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.QDNOMXþQHUmgebungseinflüsse - Teil 2-64: Prüfverfahren - Prüfung Fh: Schwingen, Breitbandrauschen (digital geregelt) und LeitfadenEssais d'environnement -- Partie 2-64: Essais - Essai Fh: Vibrations aléatoires à large bande et guideEnvironmental testing -- Part 2-64: Tests - Test Fh: Vibration, broadband random and guidance19.040Preskušanje v zvezi z okoljemEnvironmental testingICS:Ta slovenski standard je istoveten z:EN 60068-2-64:2008SIST EN 60068-2-64:2008en01-november-2008SIST EN 60068-2-64:2008SLOVENSKI
STANDARDSIST EN 60068-2-64:20011DGRPHãþD

EUROPEAN STANDARD EN 60068-2-6 NORME EUROPÉENNE
EUROPÄISCHE NORM February 2008
CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2008 CENELEC -
All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60068-2-6:2008 E
ICS 19.040 Supersedes EN 60068-2-6:1995
English version
Environmental testing -
Part 2-6: Tests -
Test Fc: Vibration (sinusoidal) (IEC 60068-2-6:2007)
Essais d'environnement -
Partie 2-6: Essais -
Essai Fc: Vibrations (sinusoïdales) (CEI 60068-2-6:2007)
Umgebungseinflüsse -
Teil 2-6: Prüfverfahren -
Prüfung Fc: Schwingen (sinusförmig)
(IEC 60068-2-6:2007)
This European Standard was approved by CENELEC on 2008-02-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this 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 (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 Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.
EN 60068-2-6:2008
- 2 -
Foreword The text of document 104/439/FDIS, future edition 7 of IEC 60068-2-6, 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 60068-2-6 on 2008-02-01. This European Standard supersedes EN 60068-2-6:1995. The major changes with regard to EN 60068-2-6:1995 concern: – the agreed wording from IEC technical committee 104 meeting held in Stockholm:2000 on the testing of soft packages; – reference to the latest version of EN 60068-2-47: Mounting; – simplification of the layout of the standard by replacing some tables with text; – addition of the test report requirements (see Clause 13). The following dates were fixed: – latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement
(dop)
2008-11-01 – latest date by which the national standards conflicting
with the EN have to be withdrawn
(dow)
2011-02-01 Annex ZA has been added by CENELEC. __________ Endorsement notice The text of the International Standard IEC 60068-2-6:2007 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 60068-2-64 NOTE
Harmonized as EN 60068-2-64:1994 (not modified). __________
- 3 - EN 60068-2-6:2008
Annex ZA
(normative)
Normative references to international publications with their corresponding European publications
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.
NOTE
When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies.
Publication Year Title EN/HD Year
IEC 60068-1
- 1) Environmental testing - Part 1: General and guidance EN 60068-1 1994 2)
IEC 60068-2-47 - 1) Environmental testing -
Part 2-47: Tests - Mounting of specimens for vibration, impact and similar dynamic tests EN 60068-2-47 2005 2)
IEC 60721-3 Series Classification of environmental conditions - Part 3: Classification of groups of environmental parameters and their severities EN 60721-3 Series
ISO 2041 - 1) Vibration and shock - Vocabulary - -
ISO/IEC 17025 2005 General requirements for the competence of testing and calibration laboratories EN ISO/IEC 17025 2005
1) Undated reference.
2) Valid edition at date of issue.
IEC 60068-2-64Edition 2.0 2008-04INTERNATIONAL STANDARD NORME INTERNATIONALEEnvironmental testing –
Part 2-64: Tests – Test Fh: Vibration, broadband random and guidance
Essais d’environnement –
Partie 2-64: Essais – Essai Fh: Vibrations aléatoires à large bande et guide
INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE WICS 19.040 PRICE CODECODE PRIXISBN 2-8318-9745-9
– 2 – 60068-2-64 © IEC:2008 CONTENTS FOREWORD.4 INTRODUCTION.6
1 Scope.7 2 Normative references.7 3 Terms and definitions.8 4 Requirements for test apparatus.12 4.1 General.12 4.2 Basic motion.12 4.3 Cross-axis motion.13 4.4 Mounting.13 4.5 Measuring systems.13 4.6 Vibration tolerances.14 4.7 Control strategy.17 4.8 Vibration response investigation.17 5 Severities.18 5.1 Test frequency range.18 5.2 RMS value of acceleration.18 5.3 Shape of acceleration spectral density curve.18 5.4 Test duration.19 6 Preconditioning.19 7 Initial measurements and functional performance test.19 8 Testing.19 8.1 General.19 8.2 Initial vibration response investigation.20 8.3 Low-level excitation for equalization prior to testing.20 8.4 Random testing.21 8.5 Final vibration response investigation.21 9 Recovery.21 10 Final measurements and functional performance.21 11 Information to be given in the relevant specification.22 12 Information to be given in the test report.22
Annex A (informative)
Standardized test spectra.24 Annex B (informative)
Guidance.30
Bibliography.34
Figure 1 – Tolerance bands for acceleration spectral density;
initial and final slope (see B.2.3).14 Figure 2 – Time history of stochastically excitation; probability density function with Gaussian (normal) distribution (Example with crest factor = 3, see also 3.14 and
4.6.2).15 Figure 3 – Statistical accuracy of acceleration spectral density versus degrees of freedom for different confidence levels (see also
4.6.3).16 SIST EN 60068-2-64:2008

60068-2-64 © IEC:2008 – 3 –
Table A.1 – Categories for spectrum: transportation.24 Table A.2 – Break points for spectrum: transportation.25 Table A.3 – Categories for spectrum: stationary installation.25 Table A.4 – Break points for spectrum: stationary installation.26 Table A.5 – Categories for spectrum: equipment in wheeled vehicles.27 Table A.6 – Break points for spectrum: equipment in wheeled vehicles.28 Table A.7 – Categories for spectrum: equipment in airplanes and helicopters.29 Table A.8 – Break points for spectrum: equipment in airplanes and helicopters.29
– 4 – 60068-2-64 © IEC:2008 INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
ENVIRONMENTAL TESTING –
Part 2-64: Tests – Test Fh: Vibration,
broadband random and guidance
FOREWORD 1)
The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical 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 IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) 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 the latter. 5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an IEC Publication. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC 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.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 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 60068-2-64 has been prepared by IEC technical committee 104: Environmental conditions, classification and methods of test. This second edition cancels and replaces the first edition, published in 1993, and constitutes a technical revision. The major changes with regard to the previous edition concern the removal of Method 1 and Method 2, replaced by a single method, and replacement of Annex A with suggested test spectra and removal of Annex C.
Also included in this revision is the testing of soft packed specimens. SIST EN 60068-2-64:2008

60068-2-64 © IEC:2008 – 5 – The text of this standard is based on the following documents: FDIS Report on voting 104/456/FDIS 104/459/RVD 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/IEC Directives, Part 2. It has the status of a basic safety publication in accordance with IEC Guide 104. A list of all the parts in the IEC 60068 series, under the general title Environmental testing, can be found on the IEC website. The committee has decided that the contents of this publication will remain unchanged until the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to the specific publication. At this date, the publication will be
• reconfirmed, • withdrawn, • replaced by a revised edition, or • amended.
– 6 – 60068-2-64 © IEC:2008 INTRODUCTION This part of IEC 60068 deals with broadband random vibration testing intended for general application to components, equipment and other products, hereinafter referred to as ”specimens”, that may be subjected to vibrations of a stochastic nature. The methods and techniques in this standard are based on digital control of random vibration. It permits the introduction of variations to suit individual cases if these are prescribed by the relevant specification. Compared with most other tests, test Fh is not based on deterministic but on statistical techniques. Broad-band random vibration testing is therefore described in terms of probability and statistical averages. It is emphasized that random testing always demands a certain degree of engineering judgement, and both supplier and purchaser should be fully aware of this fact. The writer of the relevant specification is expected to select the testing procedure and the values of severity appropriate to the specimen and its use. The test method is based primarily on the use of an electrodynamic or a servo-hydraulic vibration generator with an associated computer based control system used as a vibration testing system. Annexes A and B are informative annexes giving examples of test spectra for different environmental conditions, a list of details to be considered for inclusion in specifications and guidance. SIST EN 60068-2-64:2008

60068-2-64 © IEC:2008 – 7 – ENVIRONMENTAL TESTING –
Part 2-64: Tests-Test Fh: Vibration,
broadband random and guidance
1 Scope This part of IEC 60068 demonstrates the adequacy of specimens to resist dynamic loads without unacceptable degradation of its functional and/or structural integrity when subjected to the specified random vibration test requirements. Broadband random vibration may be used to identify accumulated stress effects and the resulting mechanical weakness and degradation in the specified performance. This information, in conjunction with the relevant specification, may be used to assess the acceptability of specimens. This standard is applicable to specimens which may be subjected to vibration of a stochastic nature resulting from transportation or operational environments, for example in aircraft, space vehicles and land vehicles. It is primarily intended for unpackaged specimens, and for items in their transportation container when the latter may be considered as part of the specimen itself. 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. This standard may be used in conjunction with IEC 60068-2-47:2005, for testing packaged products. If the specimens are subjected to vibration of a combination of random and deterministic nature resulting from transportation or real life environments, for example in aircraft, space vehicles and for items in their transportation container, testing with pure random may not be sufficient. See IEC 60068-3-8:2003 for estimating the dynamic vibration environment of the specimen and based on that, selecting the appropriate test method. Although primarily intended for electrotechnical specimens, this standard is not restricted to them and may be used in other fields where desired (see Annex A). 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. IEC 60050-300: International Electrotechnical Vocabulary – Electrical and electronic measurements and measuring instruments – Part 311: General terms relating to measurements – Part 312: General terms relating to electrical measurements – Part 313: Types of electrical measuring instruments – Part 314: Specific terms according to the type of instrument
IEC 60068-1: Environmental testing – Part 1: General and guidance IEC 60068-2-6: Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal) IEC 60068-2-47:2005, Environmental testing – Part 2-47: Tests – Mounting of specimens for vibration, impact and similar dynamic tests SIST EN 60068-2-64:2008

– 8 – 60068-2-64 © IEC:2008 IEC 60068-3-8:2003, Environmental testing – Part 3-8: Supporting documentation and guidance – Selecting amongst vibration tests
IEC 60068-5-2: Environmental testing – Part 5-2: Guide to drafting of test methods – Terms and definitions IEC 60721-3 (all parts), Classification of environmental conditions – Part 3: Classification of groups of environmental parameters and their severities IEC Guide 104, The preparation of safety publications and the use of basic safety publications and group safety publications
ISO 2041: Vibration and shock – Vocabulary 3 Terms and definitions For the purposes of this document, the following terms and definitions apply.
NOTE The terms used are generally defined in IEC 60050-300, IEC 60068-1, IEC 60068-2-6, and IEC 60068-5-2 and ISO 2041. If a definition 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
cross-axis motion motion not in the direction of the stimulus; generally specified in the two axes orthogonal to the direction of the stimulus NOTE The cross-axis motion should be measured close to the fixing points. 3.2
actual motion motion represented by the wideband signal returned from the reference point transducer 3.3
fixing point part of the specimen in contact with the fixture or vibration table 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 the mounting structure and not of the specimen. 3.4
control methods 3.4.1 single point control
control method using the signal from the transducer at the reference point in order to maintain this point at the specified vibration level 3.4.2 multipoint control
control method using the signals from each of the transducers at the checkpoints NOTE The signals are either continuously averaged arithmetically or processed by using comparison techniques, depending upon the relevant specification. See also 3.13. 3.5
gn standard acceleration due to the earth's gravity, which itself varies with altitude and geographical latitude SIST EN 60068-2-64:2008

60068-2-64 © IEC:2008 – 9 – NOTE For the purposes of this standard, the value of gn is rounded up to the nearest whole number, that is
10 m/s2. 3.6
measuring points specific points at which data are gathered for conducting the test NOTE These points are of three types, as defined in 3.7 to 3.9. 3.7
checkpoint point located on the fixture, on the vibration table or on the specimen as close as possible to one of its fixing points, and in any case, rigidly connected to it NOTE 1 A number of checkpoints are used as a means of ensuring that the test requirements are satisfied. NOTE 2 If four or fewer fixing points exist, each is used as a checkpoint. For packaged products, where a fixing point may be interpreted as the packaging surface in contact with the vibration table, one checkpoint may be used, provided that there are no effects due to resonances of the vibration table or the mounting structure in the frequency range specified for the test. If this is the case, multipoint control may be necessary, but see also NOTE 3. If more than four fixing points exist, four representative fixing points will be defined in the relevant specification to be used as checkpoints. NOTE 3 In special cases, for example for large or complex specimens, the checkpoints will be 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 with a number of fixing points, a single checkpoint (that is the reference point) may be selected for the derivation of the control signal. This signal 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 frequency of the test.
3.8
reference point (single-point control) point, chosen from amongst the checkpoints, whose signal is used to control the test, such that the requirements of this standard are satisfied 3.9
fictitious reference point (multipoint control) point, derived from multiple checkpoints either manually or automatically, the result of which is used to control the test so that the requirements of this standard are satisfied 3.10
response points specific points on the specimen from which data is gathered for the purpose of the vibration response investigation NOTE These points are not the same as checkpoints or reference points. 3.11
preferred testing axes three orthogonal axes that correspond to the most vulnerable axes of the specimen 3.12
sampling frequency number of discrete magnitude values taken per second to record or represent a time-history in a digital form 3.13
multipoint control strategies method for calculating the reference control signal when using multipoint control NOTE Different frequency domain control strategies are discussed to in 4.7.1. SIST EN 60068-2-64:2008

– 10 – 60068-2-64 © IEC:2008 3.14
averaging process of determining the control acceleration spectral density formed from the arithmetic average of the acceleration spectral densities at each frequency line of more than one checkpoint
3.15
extremal (maximum or minimum) process of determining the control acceleration spectral density formed from the maximum or minimum acceleration spectral density at each frequency line of more than one checkpoint
3.16
crest factor
ratio of the peak value to the r.m.s. value of the time history
[ISO 2041] 3.17
–3 dB bandwidth frequency bandwidth between two points in a frequency response function which are at 0,707 of the maximum response when associated with a single resonance peak 3.18
acceleration spectral density ASD mean-square value of that 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
3.19
control acceleration spectral density acceleration spectral density measured at the reference point or the fictitious reference point 3.20
control system loop sum of the following actions: – digitizing the analogue waveform of the signal derived from the reference point or fictitious reference point; – performing the necessary processing; – producing an updated analogue drive waveform to the vibration system power amplifier (see Clause B.1.) 3.21
drive signal clipping (see also Figure 1) limitation of the maximum crest factor of the drive signal effective frequency range
3.22
effective frequency range (see also Figure 1) frequency range between 0,5 times f1 and 2,0 times f2 NOTE Due to initial and final slope, the effective frequency range is higher than the test frequency range between f1 and f2. 3.23
error acceleration spectral density difference between the specified acceleration spectral density and the control acceleration spectral density SIST EN 60068-2-64:2008

60068-2-64 © IEC:2008 – 11 – 3.24
equalization
minimization of the error acceleration spectral density 3.25
final slope (see also Figure 1) part of the specified acceleration spectral density above f2 3.26
frequency resolution Be width of the frequency intervals in the acceleration spectral density in Hertz NOTE It is equal to the reciprocal of the record block length (T) in digital analysis; the number of frequency lines is equal to the number of intervals in a given frequency range 3.27
indicated acceleration spectral density estimate of the true acceleration spectral density read from the analyser presentation distorted by the instrument error and the random error 3.28
initial slope (see also Figure 1) part of the specified acceleration spectral density below f1 3.29
instrument error error associated with each analogue item of the input to the control system and control system analogue items 3.30
random error error changing from one estimate to another of the acceleration spectral density because of the limitation of averaging time and filter bandwidth in practice 3.31
record collection of equally spaced data points in the time domain that are used in the calculation of the Fast Fourier Transform 3.32
reproducibility
closeness of the agreement between the results of measurements of the same value of the same quantity, where the individual measurements are made – by different methods, – with different measuring instruments, – by different observers, – in different laboratories, – after intervals of time which are long compared with the duration of a single measurement, – under different customary conditions of use of the instruments employed NOTE The term “reproducible” also applies to the case where only certain of the preceding conditions are taken into account. [IEC 60050-300, modified] SIST EN 60068-2-64:2008

– 12 – 60068-2-64 © IEC:2008 3.33
root-mean-square value (see also Figure 2) root-mean-square value (r.m.s. value) of a single-valued function over an interval between two frequencies is the square root of the average of the squared values of all functions over the total frequency interval f1 and f2 3.34
standard deviation, σ (see also Figure 2) in vibration theory, the mean value of vibration is equal to zero; therefore for a random time history, the standard deviation is equal to the r.m.s. value 3.35
statistical accuracy ratio of true acceleration spectral density to indicated acceleration spectral density 3.36
statistical degrees of freedom (see also Figure 3) DOF for estimation of acceleration spectral density of random data with a time-averaging technique, the effective number of statistical degrees of freedom is derived from the frequency resolution and the effective averaging time 3.37
test frequency range frequency range between f1 and f2 (see Figure 1) in which the ASD is constant or shaped as given in the relevant specification 3.38
true acceleration spectral density acceleration spectral density of the random signal acting on the specimen 4 Requirements for test apparatus 4.1 General The required characteristics apply to the complete vibration system, which includes the power amplifier, vibrator, test fixture, specimen and control system when loaded for testing. The standardized test method consists of the following test sequence normally applied in each of the mutually perpendicular axes of the test specimen: 1) An initial vibration response investigation, with low level sinusoidal excitation,
or low level random excitation, (see 8.2). 2) The random excitation as the mechanical load or stress test. 3) A final vibration response investigation to compare the results with the initial one and to detect possible mechanical failures due to a change of the dynamic behaviour (see 8.2 and 8.5). Where the dynamic behaviour is known, and it is not considered relevant, or sufficient data can be gathered during the test at full level, the relevant specification may not require pre and post test vibration response investigations. 4.2 Basic motion The basic motion of the fixing points of the specimen shall be prescribed by the relevant specification. The fixing points shall have substantially identical motions in phase and amplitude and shall be rectilinear relative to the direction of excitation. If substantially identical motions are difficult to achieve, then multipoint control shall be used. SIST EN 60068-2-64:2008

60068-2-64 © IEC:2008 – 13 – NOTE For large structures and a high frequency range, for example 20 Hz – 2 000 Hz, the dynamics of the test specimen is likely to require multipoint control. 4.3 Cross-axis motion
Cross-axis motion should be checked, if required by the relevant specification, either before the test is applied by conducting a sine or random investigation at a level prescribed by the relevant specification, or during testing by utilising additional monitoring channels in the two perpendicular axes. The ASD value of each frequency at the checkpoints in both axes perpendicular to the specified axis shall not exceed the specified ASD values above 500 Hz and below 500 Hz shall not exceed –3 dB of the specified ASD values. The total r.m.s. value of acceleration in both axes perpendicular to the specified axis shall not exceed 50 % of the r.m.s. value for the specified axis. For example for a small specimen, the ASD value of the permissible cross axis motion may be limited such that it does not exceed –3 dB of the basic motion, if so prescribed by the relevant specification. At some frequencies or with large-size or high-mass specimens, it may be difficult to achieve these values. Also, in those cases where the relevant specification requires severities with a large dynamic range, it may also be difficult to achieve these. In such cases, the relevant specification shall state which of the following requirements applies: a) any cross-axis motion in excess of that given above shall be stated in the test report;
b) cross-axis motion which is known to offer no hazard to the specimen need not be monitored. 4.4 Mounting The specimen shall be mounted in accordance with IEC 60068-2-47. In any case, the transmissibility curve chosen from IEC 60068-2-47 must be squared before multiplication with the ASD spectrum. 4.5 Measuring systems The characteristics of the measuring system shall be such that it can be determined whether the true value of the vibration as measured in the intended axis at the reference point is within the tolerance required for the test. The frequency response of the overall measuring system, which includes the transducer, the signal conditioner and the data acquisition and processing device, has a significant effect on the accuracy of the measurements. The frequency range of the measuring system shall extend from at least 0,5 times the lowest frequency (f1) to 2,0 times the highest frequency (f2) of the test frequency range (see Figure 1). The frequency response of the measuring system shall be flat within ±5 % of the test frequency range. Outside of this range any further deviation shall be stated in the test report. SIST EN 60068-2-64:2008

– 14 – 60068-2-64 © IEC:2008
0,5f1 +3dB
Acceleration spectral density
(dB) Frequency
(Hz) (log. scale) –3dBInitial slope normally +6 dB/octave Final slope –24 dB/octave or steeper f1 fafbf2 2f2 IEC
581/08
Figure 1 – Tolerance bands for acceleration spectral density;
initial and final slope (see B.2.3) 4.6 Vibration tolerances 4.6.1 ASD and r.m.s. value The indicated acceleration spectral density in the required axis at the reference point between f1 and f2 in Figure 1 shall be within ±3 dB, allowing for the instrument and random error, referred to the specified acceleration spectral density.
The r.m.s. value of acceleration, computed or measured between f1 and f2, shall not deviate more than 10 % from the r.m.s. value associated with the specified acceleration spectral density. These values are valid for both the reference point and fictitious reference point. At some frequencies, or with large-size or high-mass specimens, it may be difficult to achieve these values. In such cases, the relevant specification shall prescribe a wider tolerance. The initial slope shall not be less than +6 dB/octave and the final slope shall be –24 dB/ octave or steeper (see also B.2.3). 4.6.2 Distribution The instantaneous acceleration values at the reference point shall have an approximately normal (Gaussian) distribution as given in Figure 2. If explicitly desired, a validation shall be performed during normal system calibration (see B.2.2). The drive signal clipping shall have a value of at least 2,5 (see 3.16). The crest factor of the acceleration signal at the reference point shall be examined to ensure that the signal contains peaks of at least 3 times the specified r.m.s. value, unless otherwise prescribed by the relevant specification. SIST EN 60068-2-64:2008

60068-2-64 © IEC:2008 – 15 – If a fictitious reference point is used for control, the requirement for the crest factor applies to
each individual checkpoint used to form the control acceleration spectral density. The probability density function shall be computed for the reference point for a duration of 2 min during testing. The admissible deviation from the normal distribution, Figure 2, shall be prescribed in the relevant specification.
Peak value RMS value Time Probability Peak value 3σ 2σ σ σ 2σ 3σ IEC
582/08
Figure 2 – Time history of stochastically excitation; probability density function with Gaussian (normal) distribution (example with crest factor = 3, see also 3.14 and 4.6.2)
4.6.3 Statistical accuracy The statistical accuracy is determined from the statistical degrees of freedom Nd and the confidence level (see also Figure 3). The statistical degrees of freedom are given by:
Nd = 2Be × Ta (1) where Be
is the frequency resolution; Ta
is the effective averaging time. Nd shall not be less than 120 DOF, unless otherwise specified by the relevant specification. If the relevant specification states confidence levels to be met during the test, Figure 3 should be used to calculate statistical accuracy. SIST EN 60068-2-64:2008

– 16 – 60068-2-64 © IEC:2008
5 4 3 2 1 0 –1 –2 –3 –4 dB % 300 250 200 150 100 90 80 70 60 50 40 99 % 95 % 90 % 50 % 50 % 90 % 95 % 99 % Confidence levels 30 40 50 60708090100120200300 400 500Statistical degrees of freedomStatistical accuracy IEC
629/05
Figure 3 – Statistical accuracy of acceleration spectral density versus degrees of freedom for different confidence levels (see also 4.6.3) 4.6.4 Frequency resolution The frequency resolution Be in Hz necessary to minimize the difference between the true and the indicated acceleration spectral density shall be selected by taking the digital controller frequency range divided by the number of spectral lines (n).
Be = fhigh/n (2) where fhigh is the frequency range chosen from the options provided by the digital vibration control system in Hertz and should be equal or greater than 2f2, that is fhigh ≥ 2f2, see Figure 1; n is the number of spectral lines equally spread over the frequency range to fhigh. The number of spectral lines, n, should be at least 200. Frequency resolution shall be given in the relevant specification (see also Clause 11, item j)) and stated in the test report. Be
shall be chosen such that, as a minimum, a frequency line coincides with the frequency f1 in Figure 1 and the first frequency line is at 0,5 of f1; also that two frequency lines define the initial slope. If this gives two different values then the smallest Be shall be chosen. NOTE There is a compromise between having a finer Be, resulting in a longer loop control time and better definition of the spectrum, or having a coarser Be, resulting in a shorter loop control time and worse definition of the spectrum. SIST EN 60068-2-64:2008

60068-2-64 © IEC:2008 – 17 – 4.7 Control strategy 4.7.1 Single/multipoint control When multipoint control is specified or necessary, the control strategy shall be specified. The relevant specification shall state whether single point or multipoint control shall be used. If multipoint control is prescribed, the relevant specification shall state whether the average value of the signals at the checkpoints or the extremal value out of the signals at the selected control points shall be controlled to the specified level. For multipoint control, the relevant specification should state whether an unprocessed spectrum of each of the control channels contributing to the control spectrum should be added to the test report. NOTE If it is not possible to achieve single point control, then multipoint control should be used by controlling the average or extreme value of the signals at the checkpoints. In either of these cases of multipoint control, the point is a fictitious reference point. The method used should be stated in the test report. The following strategies are available. 4.7.1.1 Averaging strategy In this method, the control value is computed from the signals from each checkpoint. A composite control value is formed by arithmetically averaging the ASD value at each frequency line from the checkpoints. This arithmetically averaged control value is then compared with the specified ASD value of each frequency. 4.7.1.2 Weighted averaging strategy The control ASD of each frequency aC is formed by averaging the ASD from the checkpoints a1 to an according to their weighting w1 to wn: aC = (w1 x a1 + w2 x a2 +….+ wn x an) / (w1 + w2 +…+ wn) This control strategy offers the possibility that different checkpoint signals contribute a different portion to the control value of each frequency. 4.7.1.3 Extremal strategy In this method, a composite control ASD is computed from the maximum (MAX) or the minimum (MIN) extreme ASD values of each frequency line measured at each checkpoint. This strategy will produce a control value of each frequency that represents the envelope of the ASD values as a function of frequency from each checkpoint (MAX) or a lower limit of the ASD values as a function of frequency from each checkpoint (MIN). 4.7.2 Multireference control If specified by the relevant specification, multiple reference spectra may be defined for different checkpoints or measuring points or different types of controlled variables, for example, for force limited vibration testing.
When multireference control is specified, the control strategy shall be either: Limiting:
All control signals shall be beneath their appropriate reference spectrum. Superseding: All control signals shall be above their appropriate reference spectrum. 4.8 Vibration response investigation The vibration response investigation is a convenient and sensitive method for the evaluation of the effects of vibration testing, see IEC 60068-3-8. Aims, purposes and methods for vibration response investigations with its advantages are explained in IEC 60068-3-8. The SIST EN 60068-2-64:2008

– 18 – 60068-2-64 © IEC:2008 requirements for sinusoidal excitation are given in test Fc (IEC 60068-2-6) and those for random excitation are given in this standard. In the case of sinusoidal excitation, it should be remembered that, in the case of non-linear resonances, the resonance frequencies will change depending on the direction of the frequency variation during the sweep. For random excitation non linearities can influence the resonance behaviour. For sinusoidal and random excitation, the amplification at resonances may be dependent on the magnitude of the input vibration. For the vibration response investigations of an ‘undefined type’ specimen or package, it may be necessary to measure different signals such as driving force or velocity. If specified by the relevant specification, for example, the spectra of the mechanical impedance of the specimen should be calculated before and after the test. NOTE Mechanical impedance and other similar terms are defined in ISO 2041. 5 Severities The test severity is determined by the combination of all the following parameters: – test frequency range; – r.m.s. value of acceleration; – shape of acceleration spectral density; – duration of testing. Each parameter shall be prescribed by the relevant specification. They may be: a) chosen from the values given in 5.1 to 5.4; b) chosen from the examples in Annex A for different environmental conditions; c) derived from the known environment if this gives significantly different values; or d) derived from other known sources of relevant data (for example IEC 60721-3). 5.1 Test frequency range If option a) is chosen, then
f1 and f2
may be chosen from the following values in Hz: a)
f1 : 1; 2; 5; 10; 20; 50; 100; b)
f2: 20; 50; 100; 200; 500; 1 000; 2 000; 5 000. Frequencies f1 and f2 and their relation to the acceleration spectral density are shown in the spectra examples in Annex A. 5.2 RMS value of acceleration If option a) is chosen, then the r.m.s. value of acceleration (nominal value in Figure 1) between f1 and f2 may be chosen from the following values in m/s2: 1; 1,4 ; 2; 2,8; 3,5; 5; 7; 10; 14; 20; 28; 35; 50; 70; 100; 140; 200; 280 NOTE The value of 10 m/s2 is ascribed to gn for the purposes of this standard. 5.3 Shape of acceleration spectral density curve This test specifies an acceleration spectral density curve with increasing, decreasing and flat horizontal portions (see spectra A.1 – A.4). For a standard test one of t
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