ISO 5344:2004
(Main)Electrodynamic vibration generating systems — Performance characteristics
Electrodynamic vibration generating systems — Performance characteristics
ISO 5344:2004 specifies the performance characteristics and performance test conditions for electrodynamic vibration generator systems and provides a list of additional equipment characteristics that can be declared by the equipment manufacturer. This information can be used by the user or the writer of specifications for equipment for the selection of such a system, taking into account its application. ISO 5344:2004 establishes procedures for calculating the system performance of a system comprising an amplifier from one source and a vibrator from a different source. Such a calculated system performance is less precise than performance measured on a system comprising the actual vibrator and amplifier, and a reserve of calculated force is recommended. It can be desirable to specify separately the acquisition of needed vibrator and/or amplifier interface data, particularly if a vibrator or amplifier is to be acquired to add to an existing installation. It can also be desirable to specify the responsibility for the calculation of performance. ISO 5344:2004 is applicable to equipment producing sine, random and impulse rectilinear vibration. It is implied that all systems are usable for sine testing at least at a low level, since sine capability is needed for specimen response evaluation and transfer function measurements for random and impulse testing. When random capability is specified, it is implied that some sine capability is also available. Similarly, when impulse capability is specified, it is implied that some sine, but not necessarily random, capability is available.
Systèmes électrodynamiques utilisés pour la génération de vibrations — Caractéristiques de performance
General Information
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 5344
Second edition
2004-07-01
Electrodynamic vibration generating
systems — Performance characteristics
Systèmes électrodynamiques utilisés pour la génération de
vibrations — Caractéristiques de performance
Reference number
©
ISO 2004
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ii © ISO 2004 – All rights reserved
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 2
4 Structure of this International Standard. 6
4.1 General. 6
4.2 Subclause coding . 6
4.3 Symbol coding . 7
5 Systems. 7
5.1 General. 7
5.2 System specifications (S,a). 7
5.3 System performance. 8
5.4 Calculated system performance. 9
6 Electrodynamic vibration generators . 10
6.1 Vibration generator specification (C,a). 10
6.2 Vibration generator performance . 11
6.3 Vibrator drive requirements. 12
6.4 Vibrator maintenance (A,a) . 15
7 Power amplifiers . 15
7.1 Amplifier specification (C,a). 15
7.2 Amplifier test loads. 16
7.3 Amplifier performance. 17
7.4 Amplifier maintenance (A,a). 19
8 Tests and measurements. 19
8.1 General. 19
8.2 Conditioning before data runs. 19
8.3 Endurance tests . 20
8.4 Spill-over limits . 21
8.5 Distortion tests. 22
8.6 Impulse generation . 24
Annex A (informative) Additional equipment characteristics . 25
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 5344 was prepared by Technical Committee ISO/TC 108, Mechanical vibration and shock, Subcommittee
SC 6, Vibration and shock generating systems.
This second edition cancels and replaces the first edition (ISO 5344:1980), which has been technically revised.
Considered responses to all of the proposed substantive changes to ISO 5344:1980 are incorporated in this
second edition. Changes favouring the specific design of individual sources were rejected. Regarding
endurance testing, a compromise is incorporated, providing a less expensive, but hopefully adequate,
assurance of reliability.
iv © ISO 2004 – All rights reserved
Introduction
Users want their equipment to operate for long period without malfunction. A major purpose of this
International Standard is to establish procedures to measure performance and to provide ways to ensure the
reliability of electrodynamic vibration generation equipment and systems. Some assurance of reliability, but
not conclusive, is provided by endurance tests on the vibrator, amplifier and the system as a whole.
If all sources of electrodynamic vibration generation equipment and systems use the same procedures, these
procedures define the meanings of the performance statements and reliability statements. Comparisons of the
performance and reliability statements of the different sources become useful.
Many of these procedures are suitable for incorporation in a purchase specification to state the acceptance
testing to be carried out upon delivery.
Others, particularly those related to endurance testing, are lengthy and expensive, and typically are performed
by the source at the end of the product development process, before the start of series production. These
procedures typically are used to establish and confirm the rated performance stated in the sales literature.
After discussions with the proposed sources, the writer of the purchase specification may propose abbreviated
procedures for equipment acceptance testing, or alternatively, may propose to accept written assurances that
the full procedures have been performed by the source with mutually satisfactory results.
INTERNATIONAL STANDARD ISO 5344:2004(E)
Electrodynamic vibration generating systems — Performance
characteristics
1 Scope
This International Standard specifies the performance characteristics and performance test conditions for
electrodynamic vibration generator systems and provides a list of additional equipment characteristics (see
Annex A) that can be declared by the equipment manufacturer. This information can be used by the user or
the writer of specifications for equipment for the selection of such a system, taking into account its application.
This International Standard establishes procedures for calculating the system performance of a system
comprising an amplifier from one source and a vibrator from a different source. Such a calculated system
performance is less precise than performance measured on a system comprising the actual vibrator and
amplifier, and a reserve of calculated force is recommended. It can be desirable to specify separately the
acquisition of needed vibrator and/or amplifier interface data, particularly if a vibrator or amplifier is to be
acquired to add to an existing installation. It can also be desirable to specify the responsibility for the
calculation of performance.
This International Standard is applicable to equipment producing sine, random and impulse rectilinear
vibration. It is implied that all systems are usable for sine testing at least at a low level, since sine capability is
needed for specimen response evaluation and transfer function measurements for random and impulse
testing. When random capability is specified, it is implied that some sine capability is also available. Similarly,
when impulse capability is specified, it is implied that some sine, but not necessarily random, capability is
available.
NOTE Three groups of people are expected to use this International Standard: the supplier of the equipment, the
purchaser of the equipment, and the organization that tests the equipment. The supplier of the equipment states that
“rated” performance is available, typically as stated in sales literature. The purchaser states the “specified” performance of
the equipment that he will accept, typically less than or equal to the rated performance. The test organization “provides”
the results of its tests and observations, typically by a written report, which may include the conditions and accuracy of
each measurement, and illustrations such as waveforms, performance graphs and tables of values.
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.
ISO 2041:1990, Vibration and shock — Vocabulary
ISO 15261, Vibration and shock generating systems — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 2041, ISO 15261 and the following
apply.
3.1
electrodynamic vibration generator
vibrator
vibration generator which derives its vibratory force from the interaction of a magnetic field of constant value,
and a coil of wire contained in it which is excited by a suitable alternating current
[ISO 2041:1990]
NOTE 1 Unless specifically restricted to the moving element, body and base of the vibrator machine, this includes the
flexible field, control and drive cables, coolant hoses, field supply, and cooling, demagnetizing, protective and safety
systems.
NOTE 2 In this International Standard, the subscript “ v ” is used to indicate vibrator, short for electrodynamic vibration
generator. The word vibrator, which has the same meaning, is the term commonly used in industry.
3.2
power amplifier
amplifier
power electronic device capable of providing the voltage and current used to drive the vibrator
NOTE Unless otherwise specified, this includes the cooling, protective and safety systems.
3.3
system
combination of a power amplifier and an electrodynamic vibration generator to provide vibratory force
NOTE The following are excluded from this International Standard, but are included in the more inclusive
electrodynamic vibration test facility system:
the input signal source and control (typically providing controlled sinusoidal, random or shock simulation signals);
specimen mounting fixtures and auxiliary tables;
measuring instrumentation (e.g. accelerometers and conditioning and analysis electronics);
mains electrical power cables and coolant hoses, or piping to and between the power amplifier, vibrator field supply,
and vibrator and amplifier cooling supplies;
air conditioning to remove generated heat not removed by the cooling systems;
a vibration-isolated inertia block to inhibit the transmission of vibratory forces from the vibrator to the surroundings.
3.4
equipment source
source
supplier of the equipment being acquired or to be used in the system
NOTE 1 When a system is purchased from a single source, that source usually is the manufacturer or his agent. When
the components of a system are being purchased from more than one source, the sources are usually the manufacturers
of the individual components or their agents. When an organization wishes to acquire a new component (e.g. a switching
amplifier) to be combined with an existing component (e.g. a vibrator in the test laboratory of the organization), the source
of the vibrator is the vibration test laboratory.
NOTE 2 The vibration test laboratory, or other similar non-commercial source, may have difficulty acquiring the data
needed to assure that the resulting system achieves the desired system specifications.
2 © ISO 2004 – All rights reserved
3.5
drive coil
component of the electrodynamic vibration generator, designed to provide, by means of interaction between
the alternative current in the drive coil and the static magnetic field, the vibratory force proportional to the drive
coil current
NOTE For most electrodynamic vibration generators, the drive coil is attached to the moving element. For
transformer coupled vibrators, the drive coil is stationary and is coupled by transformer action to a shorted ring on the
moving element.
3.6
linear power amplifier
power amplifier having an output proportional to the input
NOTE 1 Typically, the large linear power amplifiers designed to drive vibrators have low distortion (0,1 % to 0,3 %)
when they are new or well maintained, but have high internal power dissipation, so necessitate a way of disposing of the
excess heat, and are more expensive than switching power amplifiers.
NOTE 2 Small vibrators are sometimes driven by linear audio-power amplifiers or arrays of linear audio-power
amplifiers. Moderately priced units typically have 0,1 % distortion, and higher performance and price units are available
with 0,01 % distortion.
3.7
switching power amplifier
power amplifier having an output that switches alternately between a negative value and a positive value at a
high frequency
NOTE 1 If the output is positive for a greater fraction of the high frequency cycle than it is negative, the mean output is
positive. Filtering, including the effects of the drive coil inductance and the moving mass, serves to smooth the current
through the drive coil. The technique results in low internal power dissipation. Switching power amplifiers typically are
smaller and less expensive than linear power amplifiers of the same output capability, but may have higher distortion.
NOTE 2 The earlier switching power amplifiers used to drive vibrators had switching frequencies around 40 kHz and
distortions of about 5 % to 15 %. Modern switching power amplifiers are available with switching frequencies of about
150 kHz and distortion of about 1,5 % to 5 %. As faster switching transistors become available, higher switching
frequencies will be possible, and the distortion will be reduced further. When switching frequencies reach the megahertz
region, substantial feedback around the output stage is possible, and the switching amplifier distortion will reach the 0,1 %
to 0,3 % range of the linear power amplifiers.
3.8
force
vibratory force resulting from a varying current, in a steady magnetic field, which is applied to the structure of
the moving element and the attached specimen
NOTE Due to losses, resonances and travel limitations, not all of this force is available to accelerate the moving
element and attached specimen and/or to deflect the moving element suspension springs. The magnitude of the force is
defined by the resulting acceleration:
F=+mm a
( )
et
where m and m are the masses of the moving element and attached load, respectively, and a is the resulting
e t
acceleration. This definition applies to sine, random and impulse functions of a and F .
3.9
frequency range f to f
min max
frequency range over which the full rated performance of a variable can be achieved
NOTE 1 Since the frequency range for one variable differs from the frequency range of another variable, the frequency
range should be separately specified for each variable and for each load.
NOTE 2 With regard to the force-generating capability, the values of f and f should be individually specified
min max
for both vibrator and system rated sine, random and impulse forces for each of the masses m , and for the amplifier rated
t
sine, random, and impulse output. If factors other than the force-generating capability limit the frequency range of
operation, they should be specified.
EXAMPLE
a) At low frequencies, examples of areas that may cause problem are
ratio of body mass to moving mass,
the pedestal-body suspension stroke limitations,
distortion,
transverse motion,
the moving element stroke limitations,
moving element side load capability, and
moving element suspension heating.
b) At high frequencies, examples of areas that may cause problems are
moving element mechanical resonance,
diaphragmatic effect of the moving element table (diaphragming),
distortion,
transverse motion, and
moving element to load stiffness.
3.10
test mass
m
t
mechanical mass used for the testing of systems and electrodynamic vibration generators
NOTE Except for the special case of m , the subscript “ t ” indicates the magnitude of the mass by the magnitude of
the sinusoidal acceleration achievable with the mass:
m is the special case of zero load, where only the moving element is driven;
m means that 10 m/s ( ≈ 1g ) is achievable;
1 n
m means that 40 m/s ( ≈ 4g ) is achievable;
4 n
m means that 100 m/s ( ≈ 10g ) is achievable;
10 n
m means that 200 m/s ( ≈ 20g ) is achievable;
20 n
m means that 400 m/s ( ≈ 40g ) is achievable.
40 n
Unless otherwise specified, only m , m and m are used.
0 10 40
3.11
amplifier test load
Z
a,t
electric load of the amplifier, designed to be used when testing as a system is not possible (usually because
the amplifier and vibrator sources differ)
4 © ISO 2004 – All rights reserved
NOTE Tests with the loads Z are used to acquire data for the prediction of system performance. The subscript t
a,t
indicates the operation mode: s for sine, r for random, and i for impulse. See 7.2 for properties and the calculation of load
magnitudes.
3.12
amplifier apparent power
product of the amplifier output current and the amplifier output voltage under specified conditions
NOTE See Note to 7.1.2 for improved size designation.
3.13
standard random spectral shape
random motion spectrum of the following shape, unless otherwise specified:
Φ ( f ) = 0 for f < 20 Hz;
f
ΦΦ()f = for 20 Hz u f < 100 Hz (20 dB per decade)
ΦΦ( f ) = for 100 Hz u f < 2 000 Hz (constant)
2000
−4
ΦΦf < or 10Φ for fW 2 000 Hz (allowable spill-over)
()
00
f
NOTE Φ f is the magnitude of the acceleration spectral density function, defined as the limit as ∆f approaches 0
( )
of af∆ , where a is the root-mean-square value of a narrow-band random acceleration of bandwidth ∆f centred
n n
about the frequency f .
3.14
impulse
short-duration waveform used to provide a shock excitation to the specimen
NOTE 1 There should be agreement on the acceleration time history of the impulse to be used before any of the
impulse clauses of this International Standard may be used.
NOTE 2 An impulse is specified by an acceleration time history. For electrodynamic systems, the frequency
components of the acceleration time history or of the wavelets used to produce an acceleration response spectrum are
specified over the frequency range.
NOTE 3 Typically, the high frequency spill-over problems of impulse testing are more severe than for random vibration
testing because the high amplifier output, and clipping, generate larger distortion components.
NOTE 4 Vibrators with transformer driver coils sometimes are used for high acceleration impulses. Typically, such
vibrators have the advantage of very strong moving elements. As a disadvantage, they have displacement limits that are
particularly serious for the smaller vibrators. Moving element cooling of the strongest types of these vibrators is difficult,
which may be a problem if the same vibrator is to be used for sine and random testing as well as for impulse testing.
3.15
spill-over
undesired vibration (or signal) in the frequency range higher than the specified frequency range
EXAMPLE For vibration tests specified only to 2 000 Hz, spill-over is vibration excitation above 2 000 Hz.
NOTE Typically, spill-over is caused by loose elements of the moving element or test load, inadequate filtering, or by
excessive current distortion.
3.16
distortion
undesired change in the waveform
[ISO 2041:1990]
NOTE 1 Distortion is distinguished from noise and hum, which are dealt with separately in this International Standard.
NOTE 2 For a good electrodynamic vibration generating system, the presence of distortion is a very sensitive indication
that something is wrong. Excessive distortion is a signal calling for corrective action. The user is advised to find the
problem, and correct it, before running an environmental test that would be invalid. The cause of the distortion may be
anywhere, including a loose bolt mounting the specimen to the table, a failed amplifier output transistor, an obstruction in a
cooling system, or an attempt to drive the amplifier or vibrator beyond its limits.
NOTE 3 For properly maintained electrodynamic vibration generation systems, a major cause of distortion is non-
linearity or clipping in the power amplifier. Some of the low frequency distortion, below 50 Hz to 100 Hz, is typically caused
by suspension stiffness non-linearity and/or the non-uniformity of the field in the magnetic gap. In this frequency range,
these distortions can exceed those due to power amplifier non-linearity.
NOTE 4 The distortion process generates harmonics of the input signal which excite higher frequency resonances of
the specimen. Both distortion products in the operating band, typically 20 Hz to f , and distortion products which
max
cause excitation above f are troublesome (see 3.15).
max
NOTE 5 Distortion may be specified for any variable of the system: current, voltage, acceleration, velocity or
displacement. Current distortion is the most useful distortion measure for vibration test systems. It is used to predict
system distortion and spill-over.
NOTE 6 It is tempting to specify the measurement of acceleration distortion directly, but such a measurement is unique
to the particular moving element/load combination being measured, and does not provide data that are useful for the
prediction of distortion with other table loads.
3.17
standard acceleration due to gravity
g
n
value for the acceleration due to gravity as defined for shock and vibration use in ISO 2041
NOTE 1 According to ISO 2041, g equals 9,806 65 m/s .
n
NOTE 2 In vibration testing, acceleration magnitude is often expressed as a multiple of g .
n
4 Structure of this International Standard
4.1 General
Clauses on the electrodynamic vibration generator, power amplifier and system as a whole include
subclauses giving information that the specification writer may include in his relevant specification for the
acquisition of a complete system or for components of a system.
A single relevant specification is unlikely to include all of the subclauses. For example, if only an amplifier is to
be acquired, some of the system subclauses are not necessary, and only a few of the vibrator subclauses are
needed for interface information. It is suggested that the writer of a specification read the entire standard
before selecting the subclauses needed for a particular application.
4.2 Subclause coding
A code appears after the title of each subclause as an aid to the reader and to the writer of relevant
specifications. This code has the form (X,y).
The entry at position X specifies the type of acquisition for which the subclause is applicable:
A for all acquisitions,
S only for system acquisitions, and
6 © ISO 2004 – All rights reserved
C only if a component, vibrator or amplifier, is being acquired, but not if both are being acquired.
The entry at position y specifies the type of use for which the subclause is applicable:
a for all,
s for sine,
r for random, and
i for impulse.
4.3 Symbol coding
Symbols used frequently in the text are coded as K :
g,h
symbol K means F for force, t for time to temperature stabilization, I for current, V for voltage, Z for
amplifier load, and d for distortion;
subscript g means s for system, v for vibration generator, and a for amplifier;
subscript h means s for sine, r for random, and i for impulse.
5 Systems
5.1 General
The performance of both vibrators and amplifiers deteriorates as the operating temperature increases. When
performance is specified for continuous operation, as is typical for sine and random testing, the performance
tests shall be taken after a conditioning heat run to stabilize the temperature of the equipment. Exceptions to
continuous operation shall be clearly stated. For example, not all air-cooled systems will operate at high
altitudes. Also, for some vibrators, overheating and failure will occur if continuous sine operation is attempted
at certain pedestal to body suspension resonances or certain body to moving element suspension resonances.
5.2 System specifications (S,a)
The major characteristic to be specified for an electrodynamic vibration generator system is its
force-generation capability for the desired type of use (sine, random or impulse). Be sure to include the mass
of the necessary fixtures when calculating the needed force.
The system force generation capabilities shall be specified as follows:
for sine operation, the specified system force capability with test masses m and m is F (see 5.3.2
10 40 s,s
and 5.4.2);
for random operation, the specified system force capability with test masses m and m and
10 40
acceleration spectral density shape of 3.13 is F (see 5.3.3 and 5.4.3);
s,r
for impulse operation, the specified system force capability with test masses m and m is F
10 40 s,i
(see 5.3.4 and 5.4.4); the impulse acceleration time history to be produced (see 8.6) shall also be
specified.
If the power amplifier of the system is large, the system force capability and the vibrator force capability are
the same.
If the power amplifier is small, the system force capability is less than the force capability of the vibrator.
The system performance tests (see 5.3) apply if the system is to be acquired and tested as a whole, including
both the power amplifier and the electrodynamic vibration generator. Typically this is the situation when both
the vibration generator and the power amplifier are acquired together from the same source.
When the system is to be acquired as a whole, particularly when the capabilities of the amplifier match the
requirements of the vibrator, the system performance tests provide an adequate test of the performance of the
amplifier and the vibrator, and individual tests on the amplifier and the vibrator (as components) are not
required.
If, however, it is probable that the vibrator will be used with other amplifiers, or that the amplifier is likely to be
used with other vibrators, now or in the future, the individual performances of the vibrator and the amplifier
should be specified (see 6.2 and 7.3).
Optionally, it may be specified that no-load maximum acceleration current-to-acceleration distortion or fuzz of
the vibrator shall not exceed X %, where X typically is 1 to 3 for general-purpose vibration generators used
for wide bandwidth sine/random testing. A larger value for X may be allowable for many uses of long stroke
vibration generators, particularly those with rolling element guidance.
The system performance tests apply if the components are purchased from the same source.
When the system is to be assembled from components, the components shall be individually specified and
tested (see 6.1 to 6.3; 7.1 to 7.3).
When the test procedures are used, the acquisition of accurate interface data from the two sources and the
calculation of the system forces shall also be specified.
5.3 System performance
5.3.1 General (S,a)
System performance includes
force capability for continuous operation (see 8.2),
displacement capability, between mechanical stops,
allowable velocity, and
reliable operation.
The endurance tests (see 8.3) provide some assurance of reliable operation.
The system performance test report shall give the information listed in 5.3.2 to 5.3.4.
5.3.2 System sine performance (S,s)
For the system sine conditioning run (see 8.2.1 and 8.2.2) at the force F and with the test mass m ,
s,s 10
provide the time to temperature stabilization, t , and any abnormalities or deviations from an uneventful run.
s,s
For the system sine endurance test (see 8.3) at the force F , provide the actual time duration of the
s,s
endurance test (at least 10 t unless otherwise specified). During the test, measure and report the
s,s
temperatures of the vibrator body iron, moving element, vibrator cooling air/water/oil, room ambient air,
coolant-to-vibrator cooling system, cooling air/water to the amplifier and amplifier cooling system, and the
maximum and minimum values of the main power voltage. Also provide a description of any abnormalities or
deviations from an uneventful test and the results of an after-test inspection to determine if any changes or
damage to the vibrator, vibrator cooling system, amplifier or amplifier cooling system have occurred.
Ensure that the system achieves the manufacturer's rated displacement and velocity.
Measure the spill-over acceleration and ensure that the limit specified in 8.4 has not been exceeded.
8 © ISO 2004 – All rights reserved
5.3.3 System random performance (S,r)
For the system random conditioning run (see 8.2.1 and 8.2.3) at the force F and with the test mass m ,
s,r 10
provide the time to temperature stabilization t and any abnormalities or deviations from an uneventful run.
s,r
For the system random endurance test (see 8.3) at the force F , provide the actual time duration of the
s,r
endurance test (at least 10 t unless otherwise specified). During the test, measure and report the
s,r
temperatures of the vibrator body iron, moving element, vibrator cooling air/water/oil, room ambient air,
coolant-to-vibrator cooling system, cooling air/water to the amplifier and amplifier cooling system, and the
maximum and minimum values of the main power voltage. Also provide a description of any abnormalities or
deviations from an uneventful test and the results of an after-test inspection to determine if any changes or
damage to the vibrator, vibrator cooling system, amplifier or amplifier cooling system have occurred.
If the manufacturer's rated random displacement and/or velocity are greater than the sine performance rating,
confirm that the rated random values have been achieved.
Measure the spill-over acceleration and ensure that the limit specified in 8.3 has not been exceeded.
5.3.4 System impulse performance (S,i)
The system impulse time history test requires generation of the specified acceleration time history by the
procedure of 8.6.
For the system impulse endurance test (see 8.3.6) with the mass m , provide the actual time duration of the
system impulse endurance test (at least 10t unless otherwise specified), the impulse acceleration time
s,s
histories at both the start and the end of the tests, any abnormalities or deviations, and the results of an
after-test inspection to determine if any changes or damage to the vibrator or amplifier have occurred.
For the system impulse endurance test with the mass m , provide the actual time duration of the system
impulse endurance test (at least 10t unless otherwise specified), the impulse acceleration time histories at
s,s
both the start and the end of the tests, any abnormalities or deviations, and the results of an after-test
inspection to determine if any changes or damage to the vibrator or amplifier have occurred.
If the manufacturer's rated impulse displacement and/or velocity are greater than the sine performance rating,
confirm that the rated impulse values have been achieved.
Measure the spill-over acceleration and confirm that the limit specified in 8.4 has not been exceeded.
5.4 Calculated system performance
5.4.1 General (C,a)
The calculated system performance requires the amplifier current and voltage capabilities as specified in 7.1
and confirmed by test in 7.3.
Also required are the vibrator force capabilities as specified in 6.1 and confirmed by test in 6.2.
Also required are the vibrator drive requirements as measured in 6.3.
5.4.2 Calculated system sine performance (C,s)
Referring to the amplifier capabilities and the vibrator requirements, two ratios are calculated:
I V
a,s a,s
K = and K =
i,s v,s
I V
v,s v,s
The available system force is F =KF , where K is the smaller of K or K , but is not greater than 1.
s,s v,s i,s v,s
5.4.3 Calculated system random performance (C,r)
Referring to the amplifier capabilities and the vibrator requirements, two ratios are calculated:
I V
a,r a,r
K = and K =
i,r v,r
I V
v,r v,r
The available system force is F =KF , where K is the smaller of K or K , but is not greater than 1.
s,r v,r i,r v,r
5.4.4 Calculated system impulse performance (C,i)
Referring to the amplifier capabilities and the vibrator requirements, two ratios are calculated:
I V
a,i a,i
K = and K =
i,i v,i
I V
v,i v,i
The available system force is F =KF , where K is the smaller of K or K , but is not greater than 1.
s,s v,s i,i v,i
6 Electrodynamic vibration generators
6.1 Vibration generator specification (C,a)
The major characteristic to be specified for an electrodynamic vibration generator is its force-generation
capability for the desired type of use (sine, random or impulse). Be sure to include the mass of the required
support fixtures when calculating the force needed.
The vibration generator force generation capabilities shall be specified as follows:
for sine operation, the specified vibrator force capability with test masses m and m is F
10 40 v,s
(see 6.2.2);
for random operation, the specified vibrator force capability with test masses m and m and with the
10 40
acceleration density spectral shape of 3.13 is F (see 6.2.3);
v,r
for impulse operation, the specified vibrator force capability with test masses m and m is F
10 40 v,i
(see 6.2.4); the impulse acceleration time history to be produced (see 8.6) shall also be specified.
These vibrator maximum force capabilities are available when the vibrator is driven with an amplifier of
adequate size. In this International Standard, this amplifier is described as a large amplifier to distinguish it
from the amplifier to be used with the vibrator in the actual system, which may have limitations which preclude
the availability of these vibrator maximum force capabilities.
If the vibrator is acquired in a system, the vibration generator force generation capabilities shall be specified.
The system tests confirm that the vibrator performance is adequate for the system force specified for each
type of use.
Optionally, testing of the vibrator as a component may be specified, which is particularly important if the initial
system includes an amplifier significantly smaller than the large amplifier, and if a future increase of amplifier
size may occur.
Optionally, the maximum value of the full current-to-acceleration distortion may be provided (see 6.3.2).
10 © ISO 2004 – All rights reserved
6.2 Vibration generator performance
6.2.1 General (C,a)
Vibrator performance includes
force capability for continuous operation (see 8.2),
displacement capability, between mechanical stops,
allowable velocity, and
reliable operation.
The endurance tests (see 8.3) provide some assurance of reliable operation.
The performance of this clause is specified for a vibrator to be acquired as a component. Optionally, it may be
specified for a vibrator to be acquired in a system.
This performance is demonstrated with a large amplifier. The performance test report shall provides the
information listed in 6.2.2 to 6.2.4.
6.2.2 Vibrator sine performance (C,s)
For the vibrator sine conditioning run (see 8.2.1 and 8.2.2) at the force F and with the test mass m ,
v,s 10
provide the time to temperature stabilization t (see 8.2.2) and any abnormalities or deviations.
v,s
Immediately after the sine conditioning run, take the data of 6.3.2 using the mass m .
Change the test mass to m , repeat the conditioning run until the same temperatures are achieved, and take
the data of 6.3.2 using the mass m .
For the vibrator sine endurance test (see 8.3) at the force F , provide the actual time duration of the
v,s
endurance test (at least 10 t unless otherwise specified). During the test, measure and report the
v,s
temperatures of the vibrator body iron, moving element, vibrator cooling air/water/oil, room ambient air, and
the coolant-to-vibrator cooling system. Also provide a description of any abnormalities or deviations and the
results of an after-test inspection to determine if any changes or damage to the vibrator or vibrator cooling
system have occurred.
Confirm that the vibrator achieves the manufacturer's rated displacement and velocity.
6.2.3 Vibrator random performance (C,r)
For the vibrator random conditioning run (see 8.2.1 and 8.2.3) at the force F and with the test mass m ,
v,r 10
provide the time to temperature stabilization t (see 8.2.3) and report any abnormalities or deviations.
v,r
Immediately after the random conditioning run, take the data of 6.3.4 using the mass m .
Change the test mass to m , repeat the conditioning run until the same temperatures are achieved, and take
the data of 6.3.4 using the mass m .
For the vibrator random endurance test (see 8.3) at the force F , provide the actual time duration of the
v,r
endurance test (at least 10 t unless otherwise specified). During the test, measure and report the
v,r
temperatures of the vibrator body iron, moving element, vibrator cooling air/water/oil, room ambient air, and
coolant-to-vibrator cooling system. Also provide a description of any abnormalities or deviations and the
results of an after-test inspection to determine if any changes or damage to the vibrator or vibrator cooling
system have occurred.
If the manufacturer's rated random displacement and/or velocity are greater than the sine performance rating,
confirm that the rated random values have been achieved.
6.2.4 Vibrator impulse performance (C,i)
The vibrator impulse time history test requires the generation of the specified acceleration time history by the
procedure of 8.6.
Provide the m vibrator impulse current and voltage time history waveforms for the specified acceleration
time history with the test mass m .
Provide the m vibrator impulse current and voltage time history waveforms for the specified acceleration
time history with the test mass m .
For the vibrator impulse endurance test with the mass m , provide the actual time duration of the vibrator
impulse endurance test (at least 10t unless otherwise specified), the impulse acceleration time histories at
v,s
both the start and the end of the test, any abnormalities or deviations, and the results of an after-test
inspection to determine if any changes or damage to the vibrator have occurred.
For the vibrator impulse endurance test with the mass m , provide the actual time duration of the vibrator
impulse endurance test (at least 10t unless otherwise specified), the impulse acceleration time histories at
v,s
both the start and the end of the test, any abnormalities or deviations from an uneventful test, and the results
of an after-test inspection to determine if any changes or damage to the vibrator have occurred.
If the manufacturer's rated impulse displacement and/or velocity are greater than the sine performance rating,
confirm that the impulse values have been achieved.
6.3 Vibrator drive requiremen
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