SIST EN 60068-2-27:2009

Environmental testing -- Part 2-27: Tests - Test Ea and guidance: Shock

This part of IEC 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 IEC 60068-2-47, this standard may be used for testing packaged products. This possibility was included in the 2005 version of IEC 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). For 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.

Umgebungseinflüsse - Teil 2-27: Prüfverfahren - Prüfung Ea und Leitfaden: Schocken

Essais d'environnement -- Partie 2-27: Essais - Essai Ea et guide: Chocs

CEI 60068-2-27 fournit un mode opératoire normalisé pour déterminer l'aptitude d'un spécimen à supporter  des chocs répétitifs ou non répétitifs de sévérités spécifiées. Le but de cet essai est de mettre en évidence une défaillance mécanique et/ou une dégradation des performances spécifiées, ou les dommages ou dégradations cumulés dus aux chocs. Il peut aussi être utilisé dans certains cas, conjointement à la spécification particulière, pour déterminer la robustesse de structure des spécimens ou comme essai d'assurance de la qualité. Cet essai est en premier lieu destiné aux spécimens non emballés et aux éléments placés dans leur coffret de transport lorsque ce dernier peut être considéré comme faisant partie du spécimen. Si un élément est à soumettre aux essais en étant non emballé, il est désigné comme un spécimen d'essai. Cependant, si l'élément est emballé, alors il est lui-même désigné comme produit et l'élément et son emballage sont désignés comme spécimen d'essai. Lorsque cette norme est utilisée conjointement avec la CEI 60068 2 47, elle peut être utilisée pour l'essai des produits emballés. Cette possibilité a été incluse dans la version de 2005 pour la première fois. La rédaction de cette norme s'appuie sur des formes d'impulsions prescrites. Un guide pour la sélection et l'application de ces impulsions est donné à l'Annexe A et les caractéristiques des différentes formes d'impulsion sont exposées à l'Annexe B. Chaque fois que possible, il convient que la sévérité d'essai et la forme de l'impulsion de choc appliquée au spécimen soient telles qu'elles reproduisent les effets du transport ou des conditions d'environnement réels auxquels le spécimen sera soumis ou qu'elles correspondent aux exigences de la conception si l'objet de l'essai est d'estimer la robustesse de structure (voir Articles A.2 et A.4). Pour les besoins de cet essai, le spécimen est toujours monté sur le bâti de fixation ou sur la table de la machine d'essai au choc pendant l'épreuve. Les modifications principales par rapport à l'édition précédente sont les suivantes: - la fusion de la CEI 60068-2-29 dans la présente édition de la CEI 60068-2-27; la Partie 2-29 sera supprimée dès que cette édition sera publiée;  - l'introduction de spécimens dans emballages mous comme définis dans le document du groupe de travail ad hoc de la CEI conclu à Stockholm en 2000. A le statut d'une publication fondamentale de sécurité conformément au Guide 104 de la CEI.

Okoljsko preskušanje - 2-27. del: Preskusi - Preskus Ea in vodilo: Udarec

General Information

• Status: Published
• Publication Date: 10-Jun-2009
• ICS: 19.040 - Environmental testing
• Technical Committee: I09 - Imaginarni 09
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 19-May-2009
• Due Date: 24-Jul-2009
• Completion Date: 11-Jun-2009
• Ref Project: EN 60068-2-27:2009 - Environmental testing - Part 2-27: Tests - Test Ea and guidance: Shock

Relations

• Replaces: SIST EN 60068-2-27:2001 - Basic environmental testing procedures - Part 2: Tests - Test Ea and guidance: Shock
• Effective Date: 01-Jul-2009
• Replaces: SIST EN 60068-2-27:2001 - Basic environmental testing procedures - Part 2: Tests - Test Ea and guidance: Shock
• Effective Date: 29-Jan-2023
• Replaces: SIST EN 60068-2-29:2001 - Environmental testing -- Part 2: Tests - Test Eb and guidance: Bump
• Effective Date: 29-Jan-2023
• Replaces: SIST EN 60068-2-29:2001 - Environmental testing -- Part 2: Tests - Test Eb and guidance: Bump
• Effective Date: 01-Jul-2009
• Replaces: SIST EN 60068-2-29:2001 - Environmental testing -- Part 2: Tests - Test Eb and guidance: Bump
• Effective Date: 07-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 60068-2-27:2009
01-julij-2009
1DGRPHãþD
SIST EN 60068-2-27:2001
SIST EN 60068-2-29:2001
Okoljsko preskušanje - 2-27. del: Preskusi - Preskus Ea in vodilo: Udarec
Environmental testing -- Part 2-27: Tests - Test Ea and guidance: Shock
Umgebungseinflüsse - Teil 2-27: Prüfverfahren - Prüfung Ea und Leitfaden: Schocken
Essais d'environnement -- Partie 2-27: Essais - Essai Ea et guide: Chocs
Ta slovenski standard je istoveten z: EN 60068-2-27:2009
ICS:
19.040 Preskušanje v zvezi z Environmental testing
okoljem
SIST EN 60068-2-27:2009 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60068-2-27:2009

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SIST EN 60068-2-27:2009

EUROPEAN STANDARD
EN 60068-2-27

NORME EUROPÉENNE
May 2009
EUROPÄISCHE NORM

ICS 19.040 Supersedes EN 60068-2-27:1993 and EN 60068-2-29:1993


English version


Environmental testing -
Part 2-27: Tests -
Test Ea and guidance: Shock
(IEC 60068-2-27:2008)


Essais d'environnement -  Umgebungseinflüsse -
Partie 2-27: Essais - Teil 2-27: Prüfverfahren -
Essai Ea et guide: Chocs Prüfung Ea und Leitfaden: Schocken
(CEI 60068-2-27:2008) (IEC 60068-2-27:2008)




This European Standard was approved by CENELEC on 2009-04-22. 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.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: avenue Marnix 17, B - 1000 Brussels


© 2009 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60068-2-27:2009 E

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SIST EN 60068-2-27:2009
EN 60068-2-27:2009 – 2 –
Foreword
The text of document 104/448/FDIS, future edition 4 of IEC 60068-2-27, 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 60068-2-27 on 2009-04-22.
This European Standard supersedes EN 60068-2-27:1993 and EN 60068-2-29:1993.
The major technical changes with regard to EN 60068-2-27:1993 concern:
– the merging of EN 60068-2-29:1993 into this Part 2-27;
– the introduction of soft packaged specimens as defined in the IEC ad hoc working group document
agreed in Stockholm:2000.
This standard is to be used in conjunction with EN 60068-1.
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) 2010-02-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2012-05-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60068-2-27:2008 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60068-2-31 NOTE  Harmonized as EN 60068-2-31:2008 (not modified).
IEC 60068-2-81 NOTE  Harmonized as EN 60068-2-81:2003 (not modified).
ISO/IEC 17025 NOTE  Harmonized as EN ISO/IEC 17025:2005 (not modified).
__________

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SIST EN 60068-2-27:2009
– 3 – EN 60068-2-27:2009

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

1) 2)
IEC 60068-1 - Environmental testing - EN 60068-1 1994
Part 1: General and guidance


IEC 60068-2-47 2005 Environmental testing - EN 60068-2-47 2005
Part 2-47: Tests - Mounting of specimens
for vibration, impact and similar dynamic tests


1) 2)
IEC 60068-2-55 - Environmental testing - EN 60068-2-55 1993
Part 2-55: Tests - Test Ee and guidance:
Bounce


1) 2)
IEC 60721-3-1 - Classification of environmental conditions - EN 60721-3-1 1997
Part 3: Classification of groups of
environmental parameters and their
severities -
Section 1: Storage


1) 2)
IEC 60721-3-5 - Classification of environmental conditions - EN 60721-3-5 1997
Part 3: Classification of groups of
environmental parameters and their
severities -
Section 5: Ground vehicle installations


1)
IEC Guide 104 - The preparation of safety publications – –
and the use of basic safety publications
and group safety publications




1)
Undated reference.
2)
Valid edition at date of issue.

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SIST EN 60068-2-27:2009

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SIST EN 60068-2-27:2009
IEC 60068-2-27
Edition 4.0 2008-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Environmental testing –
Part 2-27: Tests – Test Ea and guidance: Shock

Essais d'environnement –
Partie 2-27: Essais – Essai Ea et guide: Chocs

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
W
CODE PRIX
ICS 19.040 ISBN 2-8318-9628-2

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SIST EN 60068-2-27:2009
– 2 – 60068-2-27 © IEC:2008
CONTENTS
FOREWORD.4
INTRODUCTION.6

1 Scope.7
2 Normative references.7
3 Terms and definitions .8
4 Description of test apparatus .9
4.1 Required characteristics .9
4.2 Measuring system.11
4.3 Mounting .12
5 Severities .13
6 Preconditioning.14
7 Initial measurements and functional performance test .15
8 Testing .15
9 Recovery .15
10 Final measurements .15
11 Information to be given in the relevant specification.15
12 Information to be given in the test report .16

Annex A (normative) Selection and application of pulse shapes – Guidance.17
Annex B (informative) Shock response spectra and other characteristics of pulse
shapes.27
Annex C (informative) Comparison between impact tests.36

Bibliography .37

Figure 1 – Pulse shape and limits of tolerance for half-sine pulse .10
Figure 2 – Pulse shape and limits of tolerance for final-peak saw-tooth pulse.10
Figure 3 – Pulse shape and limits of tolerance for trapezoidal pulse.11
Figure 4 – Frequency characteristics of the overall measuring system .12
Figure A.1 – Shock response spectrum of a symmetrical half-sine pulse.19
Figure A.2 – Shock response spectrum of a final-peak saw-tooth pulse .20
Figure A.3 – Shock response spectrum of a symmetrical trapezoidal pulse .21
Figure B.1 – Framework or box containing oscillatory systems of which f , f and f are
1 2 3
examples of resonance frequencies .27
Figure B.2a – Exciting pulse.29
Figure B.2b – Responses for f , f and f .29
1 2 3
Figure B.2c – Spectra which result from an infinite number of frequencies, with f , f and
1 2
f shown as finite points on the continuous curves.29
3
Figure B.2 – Shock response spectrum concept .29
Figure B.3 – Framework containing damped multi-degree-of-freedom system .31
Figure B.4 – Shock response spectrum of a half-sine pulse with ripple.33

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SIST EN 60068-2-27:2009
60068-2-27 © IEC:2008 – 3 –
2
Figure B.5 – Spectrum of a final-peak saw-tooth 300 m/s , 18 ms pulse compared with
2
the spectra of 200 m/s half-sine pulses with durations between 3 ms and 20 ms .35

Table 1 – Severities for shock testing .14
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

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SIST EN 60068-2-27:2009
– 4 – 60068-2-27 © IEC:2008
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

ENVIRONMENTAL TESTING –

Part 2-27: Tests – Test Ea and guidance: Shock


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 60068-2-27 has been prepared by IEC technical committee 104:
Environmental conditions, classification and methods of test
This fourth edition cancels and replaces the third edition, published in 1987, and includes the
merging of IEC 60068-2-29, second edition (1987). It constitutes a technical revision.
The major changes with regard to the previous edition concern:
− the merging of IEC 60068-2-29 into this edition of IEC 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.

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SIST EN 60068-2-27:2009
60068-2-27 © IEC:2008 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
104/448/FDIS 104/457/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.
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 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.

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SIST EN 60068-2-27:2009
– 6 – 60068-2-27 © IEC: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-repetitive or
repetitive shocks of standard pulse shapes with specified peak acceleration and duration.
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.

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SIST EN 60068-2-27:2009
60068-2-27 © IEC:2008 – 7 –
ENVIRONMENTAL TESTING –

Part 2-27: Tests – Test Ea and guidance: Shock



1 Scope
This part of IEC 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 IEC 60068-2-47, this standard may be used for
testing packaged products. This possibility was included in the 2005 version of IEC 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).
For 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.
IEC 60068-1, Environmental testing – Part 1: General and guidance
IEC 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

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SIST EN 60068-2-27:2009
– 8 – 60068-2-27 © IEC:2008
IEC 60721-3-1, Classification of environmental conditions – Part 3: Classification of groups of
environmental parameters and their severities – Section 1: Storage
IEC 60721-3-5, Classification of environmental conditions – Part 3: Classification of groups of
environmental 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 and definitions apply.
[1]
1
NOTE The terms used are, for the most part, defined in ISO 2041 or IEC 60068-1. The following additional
terms and definitions are also applicable for the purposes of this standard.
3.1
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.
NOTE 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 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
where there are a number of fixing points, a single check point (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.
3.2
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 the
mounting structure and not of the specimen.
3.3
g
n
standard acceleration due to the earth's gravity, which itself varies with altitude and
geographical latitude
2
NOTE For the purposes of this standard, the value of g is rounded up to the nearest unity, that is 10 m/s .
n
3.4
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
shocks
___________
1
 Figures in square brackets refer to the bibliography.

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SIST EN 60068-2-27:2009
60068-2-27 © IEC:2008 – 9 –
3.6
velocity change
absolute value of the sudden change of velocity resulting from the application of the specified
acceleration
NOTE The change of velocity is normally considered sudden if it takes place in a time that is short compared with
the fundamental period of the test specimen.
4 Description of test apparatus
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.
The 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 practicable 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).

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SIST EN 60068-2-27:2009
– 10 – 60068-2-27 © IEC:2008


Integration time
1,5 D
1,2 A
   A
0,8 A
+0,2 A
 0,2 A  0,2 A
 0  0
–0,2 A –0,2 A
0,4 D 0,1 D
D D
2,5 D 2,5 D
2,4 D = T
1
6 D = T
2
IEC  303/08

Key (applicable for all three Figures 1 to 3)
– – – nominal pulse A = peak acceleration of nominal pulse
limits of tolerance T = minimum time during which the pulse shall be monitored for
1
shocks produced using a conventional shock-testing machine
D = duration of nominal pulse T = minimum time during which the pulse shall be monitored for
2
shocks produced using a vibration generator
Figure 1 – Pulse shape and limits of tolerance for half-sine pulse
Integration time

1,5 D
1,2 A
   A
0,8 A
 0,2 A  0,2 A
 0  0
–0,2 A –0,2 A
0,4 D 0,1 D
0,1 D
D D
2,5 D 2,5 D
2,4 D = T
1
6 D = T
2
IEC  304/08

Figure 2 – Pulse shape and limits of tolerance for final-peak saw-tooth pulse

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SIST EN 60068-2-27:2009
60068-2-27 © IEC:2008 – 11 –
Integration time

1,5 D
0,1 D 0,1 D
1,2 A
   A
0,8 A
0,4 A
0,4 A
 0,2 A  0,2 A
 0  0
–0,2 A –0,2 A
0,4 D D D
2,5 D 2,5 D
2,4 D = T
1
6 D = T
2
IEC  305/08

Figure 3 – Pulse shape and limits of tolerance for trapezoidal pulse
4.1.2 Repetition rate
The repetition rate shall be such that the relative motion within the specimen between shocks
shall be substantially zero and the value of acceleration at the check point shall be within the
limits shown in Figure 1 (see Clause A.7).
NOTE A formula for evaluation of repetition rate is shown in Clause A.7.
4.1.3 Velocity change tolerances
For all pulse shapes, the actual velocity change shall be within ±15 % of the value
corresponding to the nominal pulse.
Where the velocity change is determined by integration of the actual acceleration pulse, this
shall be effected from 0,4 D before the pulse to 0,1 D beyond the pulse, where D is the
duration of the nominal pulse.
NOTE If the velocity change tolerance cannot be achieved without the use of elaborate facilities, the relevant
specification should state the alternative procedure to be adopted (see Clauses A.5 and A.6).
4.1.4 Cross axis motion
The positive or negative peak acceleration at the check point(s), perpendicular to the intended
shock direction, shall not exceed 30 % of the value of the peak acceleration of the nominal
pulse in the intended direction, when determined by 4.2.
NOTE If the cross axis motion tolerance cannot be achieved, the relevant specification should state the alternative
procedure to be adopted (see Clause A.5).
4.2 Measuring system
The characteristics of the measuring system shall be such that it can be determined that the
true value of the actual pulse, as measured above, in the intended direction at the
checkpoint(s) is within the tolerances required by the Figures 1, 2 and 3.
The requirements of Figure 4 apply to the frequency response of the measuring system without
the use of a low-pass filter on the control signal. When a low-pass filter is used, the
characteristics of the filter should be such that its cut-off frequency f (–3 dB point) is not lower
g
than:

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SIST EN 60068-2-27:2009
– 12 – 60068-2-27 © IEC:2008
15,
f =
g
D
where
f is the cut-off frequency of a low-pass filter in kHz;
g
D is the pulse duration in ms.
The frequency response of the overall measuring system, which includes the accelerometer,
can have a significant effect on the accuracy and shall be within the limits shown in Figure 4
(see also Clause A.5).
+1 dB
 0 dB
–1 dB
24 dB octave
–10 dB
Frequency Hz
f f f f
1 2 3 4
IEC  306/08

Duration of Low-frequency High-frequency Frequency beyond which the response
pulse cut-off cut-off may rise above +1 dB
ms Hz kHz kHz
f f f f
1 2 3 4
0,2 and 0,3 20 120 20 40
0,5 10 50 15 30
1 4 20 10 20
2and 3 2 10 5 10
6 1 4 2 4
11 0,5 2 1 2
 16, 18 and 30 0,2 1 1 2

NOTE For shocks of duration equal to or less than 0,5 ms, the value of f and f indicated in Figure 4 may be
3 4
unnecessarily high. In such instances, the relev
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