EN 60068-2-55:1993

SLOVENSKI STANDARD
01-september-2001
Basic environmental testing procedures - Part 2: Tests - Test Ee and guidance:
Bounce
Basic environmental testing procedures -- Part 2: Tests - Test Ee and guidance: Bounce
Grundlegende Umweltprüfverfahren -- Teil 2: Prüfungen - Prüfung Ee und Leitfaden:
Prellen
Essais fondamentaux climatiques et de robustesse mécanique -- Partie 2: Essais - Essai
Ee et guide: Rebondissement
Ta slovenski standard je istoveten z: EN 60068-2-55:1993
ICS:
19.040 Preskušanje v zvezi z Environmental testing
okoljem
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME CEI
INTERNATIONALE
IEC
60068-2-55
INTERNATIONAL
Première édition
STANDARD
First edition
1987-11
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Essais fondamentaux climatiques
et de robustesse mécanique –
Partie 2-55:
Essais – Essai Ee et guide: Rebondissement

Basic environmental testing procedures –
Part 2-55:
Tests – Test Ee and guidance: Bounce

CODE PRIX
N
Commission Electrotechnique Internationale
PRICE CODE
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
Pour prix, voir catalogue en vigueur

68-2-55 © I EC 1987 - 3 -
CONTENTS
Page
FOREWORD 5
PREFACE 5
Clause
O. Introduction 7
1. Object 7
2. General description 7
3. Definitions 9
4. Description of test apparatus 9
5. Severities 13
6. Pre-conditioning 13
7. Initial measurements 13
8. Conditioning 15
9. Final measurements 15
10. Information to be given in the relevant specification . . . . . . 15
FIGURES 26
Appendix A - Guidance 19
Appendix B - Comparison between impact tests 25

68-2-55 © IEC:1987 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
–––––––––
BASIC ENVIRONMENTAL TESTING PROCEDURES –
Part 2: Tests – Test Ee and guidance: Bounce
FOREWORD
1) The formal decisions or agreements of the IEC on technical matters, prepared by technical committees on
which all the National Committees having a special interest therein are represented, express, as nearly as
possible, an international consensus of opinion on the subjects dealt with.
2) They have the form of recommendations for international use and they are accepted by the National
Committees in that sense.
3) In order to promote international unification, the IEC expresses the wish that all National Committees should
adopt the text of the IEC recommendation for their national rules in so far as national conditions will permit. Any
divergence between the IEC recommendation and the corresponding national rules should, as far as possible,
be clearly indicated in the latter.
PREFACE
This standard has been prepared by subcommittee 50A: Shock and vibration tests, of IEC
technical committee 50: Environmental testing.
The text of this standard is based on the following documents:
Six Months’ Rule Report on voting
50A(CO)159 50A(CO)160
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
It has the status of a basic safety publication in accordance with IEC Guide 104.
The following IEC publications are quoted in this standard:
Publications Nos. 68-1(1982): Basic environmental testing procedures – Part 1: General and
guidance.
68-2-27 (1987): Part 2: Tests – Test Ea and guidance: Shock.
68 2-29 (1987): Test Eb and guidance: Bump.
68-2-31 (1969): Test Ec: Drop and topple, primarily for equipment-type
specimens. Amendment 1 (1982).
68-2-32 (1975): Test Ed: Free fall. Amendment 1 (1982).

Other publication quoted:
ISO 2041 (1975):Vibration and shock – Vocabulary

68-2-55 © IEC 1987 7
BASIC ENVIRONMENTAL TESTING PROCEDURES
Part 2: Tests
Test Ee and guidance: Bounce
0. Introduction
This test is applicable to components, equipment and other electro-
technical products, hereinafter referred to as "specimens", which,
during transportation on the load-carrying platform of vehicles either
not fastened down or with some degree of freedom, may be subjected
to dynamic stresses resulting from random shock conditions. The
bounce test may also be used as a means of assessing the satisfactory
design of a specimen so far as its structural integrity is concerned.
Note.- In practice, this test is primarily applicable to equipment-type
specimens.
Specification writers will find in Clause 10 a list of details to be
considered for inclusion in specifications and in Appendix A the
necessary guidance.
1. Object
To provide a standard procedure for determining the ability of a
specimen to withstand specified severities of bounce.
2. General description
This test is primarily intended for specimens prepared for trans-
portation, including specimens in their transport case when the latter
may be considered as part of the specimen itself (see also Sub-
clause A7.2 of Appendix A) .
Wherever possible, the test severity applied to the specimen shall be
related to the operational environment to which the specimen will be
subjected during transportation.
The relevant specification shall state the criteria upon which the
acceptance or rejection of the specimen is to be based. Normally, for
this test the specimen is not functioning and it is sufficient that it
should survive the conditioning.
This standard is to be used in conjunction with IEC Publication 68-1.

68-2-55 © I EC 1987
3. Definitions
Generally the terms used are defined in ISO Standard 2041 or in IEC
Publication 68-1. The following additional term and definition is also
applicable for the purposes of this standard.
g : standard acceleration due to the earth's gravity, which itself
n varies with altitude and geographical latitude.
Note. - For the purposes of this standard, the value of g is rounded
n
up to the nearest unit, that is 10 m/s2.
4. Description of test apparatus
4.1 Characteristics of the bounce tester
a) The bounce tester shall consist of a horizontal platform coupled to
shaft-driven eccentrics (see Figure 1, page 26).
b) The platform shall be of 25 ± 1 mm plywood firmly secured to a
steel frame with appropriate barriers (see Sub-clause 4.6).
c) The eccentrics shall produce a maximum peak-to-peak vertical
displacement of the upper surface of the platform, measured in the
region between the drive shafts, of 25.5 ± 0.5 mm.
The bounce tester, when loaded with the specimen and any other
d)
necessary devices for the conditioning, shall also have the
characteristics specified in the appropriate method (see Sub-
clause 4.2) .
4.2 Motion of the platform
This shall be synchronous circular (Method A) or non-synchronous
(Method B), as • prescribed in Sub-clauses 4.2.1 and 4.2.2 respect-
ively. A mechanism for producing the required motion is referred to in
Clause A3 of Appendix A and shown in Figure 1.
Method A: Synchronous circular motion
4.2.1
The motion of the platform of the bounce tester shall be such that
each point of this platform describes a circle in the vertical plane with
a diameter of 25.5 ± 0.5 mm (see Sub-clause 4.3) .
The peak acceleration of the platform shall be between 1.1 g and
1.2 g . This can be achieved with a mean shaft speed of 285
3 rév/min.
The specimen prepared as for transportation, with or without its
transport case as prescribed by the relevant specification, shall be
placed, without being attached, on the platform centrally between the
drive shafts.
-55
68 -2 © I LC 1987 - 11 -
The horizontal motion allowed by the barriers shall be adjusted to a
total of 50 ± 5 mm, that is the specimen when placed at the centre of
the platform in its normal position shall have a free movement in any
horizontal direction of a nominal 25 mm (see Sub-clause 4.6).
4.2.2 Method B: Non-synchronous motion
The motion of the platform shall vary cyclically between a linear
vertical and an oscillatory motion. This motion is produced by a
nominally vertical drive applied to the platform along two transverse
lines spaced not less than 600 mm nor more than 1 700 mm apart. The
applied peak-to-peak value of the displacement at the drive points on
the platform shall be 25.5 ± 0.5 mm.
The frequencies at the two drive points shall be related in the ratio
1 to 0.9 with a tolerance of ±0.03: the higher-speed drive shaft shall
rotate at a mean speed of 285 ± 5 rev/min .
In the direction transverse to the required motion, the displacement
shall be in principle zero except for the effects of play in the drive
mechanism.
The distance between the drive points on the platform shall normally
be greater than the longest base dimension of the specimen undergoing
test and the size of the test facility shall be chosen accordingly.
Note.-
When there is no facility fully satisfying the requirements, the
available facility may be used provided that this is stated in
the test report.
The specimen prepared as for transportation, with or without its
transport case as prescribed by the relevant specification, shall be
placed, without being attached, on the platform centrally between the
drive points.
The horizontal motion allowed by the barriers shall be adjusted to a
total of between 100 mm and 150 mm, that is the specimen when placed
at the centre -of the platform in its normal position shall have a free
movement in any horizontal direction of between 50 mm and 75 mm (see
Sub-clause 4.6) .
4.3 Horizontal accuracy of platform
The bounce tester shall be installed so that, with the eccentrics at
the lowest point, the platform is horizontal within the following
tolerances including an allowance for play in the drive mechanism:
a)
Method A: ±0.5° in the longitudinal and lateral axes;
b)
Method B: between 10' and 0.5° in the longitudinal axis and ±0.5°
in the lateral axis.
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68-2-55 © IEC 1987
4.4 Control
The acceleration of the platform is determined by the shaft speed.
The acceleration of the specimen need not be measured.
4.5 Mounting
For the purpose of this test, the specimen is never fastened or
otherwise fixed to the bounce tester during conditioning.
4.6 Horizontal motion of specimen
The horizontal motion shall be limited by suitable wooden barriers to
that required by the appropriate method (see Sub-clause 4.2). These
barriers shall simulate the resilient properties of pinewood board 50 mm
in thickness.
For both methods the top edge of the barrier shall be not more than
600 mm above the platform and shall comply with the following addi-
tional requirements:
a) Method A: it shall be at least at the height of the specimen;
b)
Method B: it shall be between 25 mm and 75 mm below the top of
the specimen.
A suitable barrier arrangement is described in Clause A2 of
Appendix A and shown in Figure 2, page 27.
5. Severities
The duration of conditioning shall be selected from the severities
given below. These severities represent the nominal duration of condi-
tioning, exclusive of recovery periods, to be applied:
180 min
60 min
15 min
5 min.
The duration of conditioning shall be divided equally between the
specified attitudes (Clauses A4 and A5 of Appendix A) .
6. Pre-conditioning
The relevant specification may call for pre-conditioning.
7. Initial measurements
The specimen shall be submitted to the visual, dimensional and
functional checks prescribed by the relevant specification.

68-2-55 © !EC 1987 - 15 -
8. Conditioning
Where the aspect ratio of the specimen (the ratio of its longest side
to its shortest) does not exceed 3:1 and the mass does not exceed
50 kg, the specimen shall be subjected to bounce on each of its faces
(for example three faces for a cylinder and six for a rectangular
object) . When placed on each face, it shall be subjected to bounce
twice, being turned through 90° in the horizontal plane between the
two bounces so that the impact with the barriers of the bounce tester
occurs along two perpendicular axes. If there is a long side to the
face, one axis of impact with the barriers shall be parallel to this.
For specimens of greater mass or aspect ratio or of a different form
the test shall be carried out as required by the relevant specification.
Where there is only a limited number of faces on which the specimen
would be transported, the relevant specification shall state the
attitude(s) of the specimen for the test (see Clause A5) .
If required by the relevant specification, specimens of any aspect
ratio may be stacked, provided that the overall height does not exceed
600 mm. The relevant specification shall state what special arrange-
ments, if any, are needed to constrain the topmost specimen.
Note.- Excessive temperature rises may occur in specimens which
contain highly resilient structures or parts, except possibly
for the severity of 5 min. In such cases it may be necessary,
in order to prevent an excessive temperature rise within the
specimen, to carry out the test in a series of phases (each of,
say, 5 min bouncing followed by a recovery period of 5 min or
longer) as required by the relevant specification.
9. Final measurements
The specimen shall be submitted to the visual, dimensional and
functional checks prescribed by the relevant specification.
The relevant specification shall provide the criteria upon which the
acceptance or rejection of the specimen is to be based.
10.
Information to be given in the relevant specification
When this test is included in a relevant specification, the following
details shall be given as far as they are applicable:
Clause and
Sub-clause
a) Acceptance and rejection criteria
(see Clause A7 of Appendix A) 2
b) Test method/motion of the platform 4.2.1 and
(see Clause A3 of Appendix A) 4.2.2

68-2-55 © IEC 1987 - 17 -
Clause and
Sub-clause
c) Testing with or without transport case
4.2.1 and
4.2.2
d) Size of test facility 4.2.2
e)
Se
...