Acoustics and vibration - Laboratory measurement of vibro-acoustic transfer properties of resilient elements - Part 1: Principles and guidelines (ISO 10846-1:2008)

This part of ISO 10846 explains the principles underlying ISO 10846-2, ISO 10846-3, ISO 10846-4 and ISO 10846-5 for determining the transfer properties of resilient elements from laboratory measurements, and provides assistance in the selection of the appropriate part of this series. It is applicable to resilient elements that are used to reduce a) the transmission of audio frequency vibrations (structure-borne sound, 20 Hz to 20 kHz) to a structure which may, for example, radiate fluid-borne sound (airborne, waterborne, or other), and b) the transmission of low-frequency vibrations (typically 1 Hz to 80 Hz), which may, for example, act upon human subjects or cause damage to structures of any size when the vibration is too severe. The data obtained with the measurement methods, which are outlined in this part of ISO 10846 and further detailed in ISO 10846- 2, ISO 10846-3, ISO 10846-4 and ISO 10846-5, can be used for product information provided by manufacturers and suppliers, in formation during product development, quality control, and calculation of the transfer of vibrations through resilient elements. The conditions for the validity of the measurement methods are a) linearity of the vibrational behaviour of the resilient elements (this includes elastic elements with non-linear static load-deflection characteristics, as long as the elements show approximate linearity for vibrational behaviour for a given static preload), and b) the contact interfaces of the vibration isolator with the adjacent source and receiver structures can be considered as point contacts.

Akustik und Schwingungstechnik - Laborverfahren zur Messung der vibro-akustischen Transfereigenschaften elastischer Elemente - Teil 1: Grundlagen und Übersicht (ISO 10846-1:2008)

Dieser Teil von ISO 10846 erläutert die Grundsätze, die den Labormessungen nach den Teilen 2 bis 5 von ISO 10846 zur Ermittlung der Transfereigenschaften elastischer Elemente zugrunde liegen und gibt Hilfestellung bei der Auswahl der jeweils geeigneten Norm dieser Reihe. Er gilt für elastische Elemente, die verwendet werden,
a)   um die Übertragung von Schwingungen im Hörbereich (Körperschall, 20 Hz bis 20 kHz) auf eine Struktur zu verringern; diese Struktur kann z. B. Schall in Fluide abstrahlen (Luftschall, Wasserschall und dergleichen);
b)   um die Übertragung tieffrequenter Schwingungen zu verringern (typischerweise 1 Hz bis 80 Hz); solche Schwingungen können z. B. auf den Menschen einwirken oder Schäden an Strukturen beliebiger Größe hervorrufen, wenn diese Schwingungen zu stark sind.
Die Werte, die nach den Messverfahren ermittelt werden, die in diesem Teil von ISO 10846 umrissen und in den Teilen 2 bis 5 von ISO 10846 detailliert dargestellt sind, können verwendet werden für
-   Produktinformationen, die Hersteller und Lieferanten zur Verfügung stellen,
-   Informationen während der Produktentwicklung,
-   Qualitätskontrolle,
-   die Berechnung der Schwingungsübertragung über ein elastisches Element.
Für die Anwendbarkeit der Messverfahren gelten die folgenden Voraussetzungen:
a)   lineares Schwingungsverhalten des elastischen Elements (dies schließt elastische Elemente mit nichtlinearer statischer Federkennlinie ein, solange sie näherungsweise lineares Schwingungsverhalten bei einer gegebenen statischen Vorlast zeigen);
b)   die Anschlussflächen, die der Schwingungsisolator mit den angrenzenden Bauteilen der Schwingungsquelle und der schwingungsaufnehmenden Struktur gemeinsam hat, können als punktförmig angesehen werden.

Acoustique et vibrations - Mesurage en laboratoire des propriétés de transfert vibro-acoustique des éléments élastiques - Partie 1: Principes et lignes directrices (ISO 10846-1:2008)

L'ISO 10846-1:2008 explique les principes de l'ISO 10846-2, l'ISO 10846-3, l'ISO 10846‑4 et l'ISO 10846-5, destinées à déterminer les propriétés de transfert des éléments élastiques à partir de mesurages en laboratoire, et elle fournit une aide pour choisir la partie appropriée de l'ISO 10846. Elle s'applique aux éléments élastiques destinés à réduire:
la transmission de vibrations de fréquence audible (bruit solidien, 20 Hz à 20 kHz) à une structure qui peut, par exemple, rayonner un bruit propagé par voie fluide (bruit aérien, propagé par l'eau ou autre); et
la transmission de vibrations de basse fréquence (généralement 1 Hz à 80 Hz) qui peuvent, par exemple, agir sur les individus ou endommager les structures de toutes dimensions lorsque la vibration est trop importante.

Akustika in vibracije - Laboratorijsko merjenje vibro-akustičnih prenosnih lastnosti elastičnih elementov - 1. del: Načela in smernice (ISO 10846-1:2008)

General Information

Status
Published
Publication Date
07-Oct-2008
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
02-Oct-2008
Due Date
07-Dec-2008
Completion Date
08-Oct-2008

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SLOVENSKI STANDARD
SIST EN ISO 10846-1:2008
01-november-2008
1DGRPHãþD
SIST EN ISO 10846-1:1999
$NXVWLNDLQYLEUDFLMH/DERUDWRULMVNRPHUMHQMHYLEURDNXVWLþQLKSUHQRVQLKODVWQRVWL
HODVWLþQLKHOHPHQWRYGHO1DþHODLQVPHUQLFH ,62
Acoustics and vibration - Laboratory measurement of vibro-acoustic transfer properties of
resilient elements - Part 1: Principles and guidelines (ISO 10846-1:2008)
Akustik und Schwingungstechnik - Laborverfahren zur Messung der vibro-akustischen
Transfereigenschaften elastischer Elemente - Teil 1: Grundlagen und Übersicht (ISO
10846-1:2008)
Acoustique et vibrations - Mesurage en laboratoire des propriétés de transfert vibro-
acoustique des éléments élastiques - Partie 1: Principes et lignes directrices (ISO 10846-
1:2008)
Ta slovenski standard je istoveten z: EN ISO 10846-1:2008
ICS:
17.140.01 $NXVWLþQDPHUMHQMDLQ Acoustic measurements and
EODåHQMHKUXSDQDVSORãQR noise abatement in general
17.160 Vibracije, meritve udarcev in Vibrations, shock and
vibracij vibration measurements
SIST EN ISO 10846-1:2008 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 10846-1:2008

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SIST EN ISO 10846-1:2008
EUROPEAN STANDARD
EN ISO 10846-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2008
ICS 17.140.01 Supersedes EN ISO 10846-1:1998
English Version
Acoustics and vibration - Laboratory measurement of vibro-
acoustic transfer properties of resilient elements - Part 1:
Principles and guidelines (ISO 10846-1:2008)
Acoustique et vibrations - Mesurage en laboratoire des Akustik und Schwingungstechnik - Laborverfahren zur
propriétés de transfert vibro-acoustique des éléments Messung der vibro-akustischen Transfereigenschaften
élastiques - Partie 1: Principes et lignes directrices (ISO elastischer Elemente - Teil 1: Grundlagen und Übersicht
10846-1:2008) (ISO 10846-1:2008)
This European Standard was approved by CEN on 12 April 2008.
CEN 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 CEN Management Centre or to any CEN 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 CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 10846-1:2008: E
worldwide for CEN national Members.

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SIST EN ISO 10846-1:2008
EN ISO 10846-1:2008 (E)
Contents Page
Foreword.3

2

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SIST EN ISO 10846-1:2008
EN ISO 10846-1:2008 (E)
Foreword
This document (EN ISO 10846-1:2008) has been prepared by Technical Committee ISO/TC 43 "Acoustics" in
collaboration with Technical Committee CEN/TC 211 “Acoustics” the secretariat of which is held by DS.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by February 2009, and conflicting national standards shall be withdrawn
at the latest by February 2009.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 10846-1:1998.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 10846-1:2008 has been approved by CEN as a EN ISO 10846-1:2008 without any
modification.

3

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SIST EN ISO 10846-1:2008

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SIST EN ISO 10846-1:2008

INTERNATIONAL ISO
STANDARD 10846-1
Second edition
2008-08-15

Acoustics and vibration — Laboratory
measurement of vibro-acoustic transfer
properties of resilient elements —
Part 1:
Principles and guidelines
Acoustique et vibrations — Mesurage en laboratoire des propriétés de
transfert vibro-acoustique des éléments élastiques —
Partie 1: Principes et lignes directrices




Reference number
ISO 10846-1:2008(E)
©
ISO 2008

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SIST EN ISO 10846-1:2008
ISO 10846-1:2008(E)
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All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
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ii © ISO 2008 – All rights reserved

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SIST EN ISO 10846-1:2008
ISO 10846-1:2008(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Selection of appropriate International Standard . 4
5 Theoretical background . 4
5.1 Dynamic transfer stiffness. 4
5.2 Dynamic stiffness matrix of resilient elements . 5
5.3 Number of relevant blocked transfer stiffnesses . 7
5.4 Flanking transmission. 8
5.5 Loss factor. 8
6 Measurement principles. 9
6.1 Dynamic transfer stiffness. 9
6.2 Direct method. 9
6.3 Indirect method. 11
6.4 Driving point method. 14
Annex A (informative) Functions related to dynamic stiffness . 16
Annex B (informative) Effect of symmetry on the transfer stiffness matrix. 17
Annex C (informative) Simplified transfer stiffness matrices. 20
Annex D (informative) Linearity of resilient elements . 22
Bibliography . 23

© ISO 2008 – All rights reserved iii

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SIST EN ISO 10846-1:2008
ISO 10846-1:2008(E)
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 10846-1 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise, and
ISO/TC 108, Mechanical vibration, shock and condition monitoring.
This second edition cancels and replaces the first edition (ISO 10846-1:1997), which has been technically
revised.
ISO 10846 consists of the following parts, under the general title Acoustics and vibration — Laboratory
measurement of vibro-acoustic transfer properties of resilient elements:
⎯ Part 1: Principles and guidelines
⎯ Part 2: Direct method for determination of the dynamic stiffness of resilient supports for translatory motion
⎯ Part 3: Indirect method for determination of the dynamic stiffness of resilient supports for translatory
motion
⎯ Part 4: Dynamic stiffness of elements other than resilient supports for translatory motion
⎯ Part 5: Driving point method for determination of the low-frequency transfer stiffness of resilient supports
for translatory motion
iv © ISO 2008 – All rights reserved

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SIST EN ISO 10846-1:2008
ISO 10846-1:2008(E)
Introduction
Passive vibration isolators of various kinds are used to reduce the transmission of vibrations. Examples
include automobile engine mounts, resilient supports for buildings, resilient mounts and flexible shaft
couplings for shipboard machinery and small isolators in household appliances.
This part of ISO 10846 serves as an introduction and a guide to ISO 10846-2, ISO 10846-3, ISO 10846-4 and
ISO 10846-5, which describe laboratory measurement methods for the determination of the most important
quantities which govern the transmission of vibrations through linear resilient elements, i.e.
frequency-dependent dynamic transfer stiffnesses. This part of ISO 10846 provides the theoretical background,
the principles of the methods, the limitations of the methods, and guidance for the selection of the most
appropriate standard of the series.
The laboratory conditions described in all parts of ISO 10846 include the application of static preload, where
appropriate.
The results of the methods are useful for resilient elements, which are used to prevent low-frequency vibration
problems and to attenuate structure-borne sound. However, for complete characterization of resilient elements
that are used to attenuate low-frequency vibration or shock excursions, additional information is needed,
which is not provided by these methods.

© ISO 2008 – All rights reserved v

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SIST EN ISO 10846-1:2008

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SIST EN ISO 10846-1:2008
INTERNATIONAL STANDARD ISO 10846-1:2008(E)

Acoustics and vibration — Laboratory measurement of vibro-
acoustic transfer properties of resilient elements —
Part 1:
Principles and guidelines
1 Scope
This part of ISO 10846 explains the principles underlying ISO 10846-2, ISO 10846-3, ISO 10846-4 and
ISO 10846-5 for determining the transfer properties of resilient elements from laboratory measurements, and
provides assistance in the selection of the appropriate part of this series. It is applicable to resilient elements
that are used to reduce
a) the transmission of audio frequency vibrations (structure-borne sound, 20 Hz to 20 kHz) to a structure
which may, for example, radiate fluid-borne sound (airborne, waterborne, or other), and
b) the transmission of low-frequency vibrations (typically 1 Hz to 80 Hz), which may, for example, act upon
human subjects or cause damage to structures of any size when the vibration is too severe.
The data obtained with the measurement methods, which are outlined in this part of ISO 10846 and further
detailed in ISO 10846-2, ISO 10846-3, ISO 10846-4 and ISO 10846-5, can be used for
⎯ product information provided by manufacturers and suppliers,
⎯ information during product development,
⎯ quality control, and
⎯ calculation of the transfer of vibrations through resilient elements.
The conditions for the validity of the measurement methods are
a) linearity of the vibrational behaviour of the resilient elements (this includes elastic elements with
non-linear static load-deflection characteristics, as long as the elements show approximate linearity for
vibrational behaviour for a given static preload), and
b) the contact interfaces of the vibration isolator with the adjacent source and receiver structures can be
considered as point contacts.
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.
1)
ISO 2041:— , Mechanical vibration, shock and condition monitoring — Vocabulary

1) To be published. (Revision of ISO 2041:1990)
© ISO 2008 – All rights reserved 1

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SIST EN ISO 10846-1:2008
ISO 10846-1:2008(E)
2)
ISO/IEC Guide 98-3 , Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM 1995)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 2041 and the following apply.
3.1
vibration isolator
resilient element
isolator designed to attenuate the transmission of the vibration in a certain frequency range
1)
NOTE Adapted from ISO 2041:— , definition 2.120.
3.2
resilient support
vibration isolator(s) suitable for supporting a machine, a building or another type of structure
3.3
test element
resilient element undergoing testing, including flanges and auxiliary fixtures, if any
3.4
blocking force
F
b
dynamic force on the output side of a vibration isolator which results in a zero displacement output
3.5
dynamic driving point stiffness
k
1,1
frequency-dependent ratio of the force phasor F on the input side of a vibration isolator with the output side
1
blocked to the displacement phasor u on the input side
1
=/F u
k
1,1
11
NOTE 1 The subscripts “1” denote that the force and displacement are measured on the input side.
NOTE 2 The value of k can be dependent on the static preload, temperature, relative humidity and other conditions.
1,1
NOTE 3 At low frequencies, elastic and dissipative forces solely determine k . At higher frequencies, inertial forces
1,1
play a role as well.
3.6
dynamic driving point stiffness of inverted vibration isolator
k
2,2
dynamic driving point stiffness, with the physical input and output sides of the vibration isolator interchanged
NOTE At low frequencies, where elastic and dissipative forces solely determine the driving point stiffness, k = k .
1,1 2,2
At higher frequencies inertial forces play a role as well and k and k will be different in case of asymmetry.
1,1 2,2

2) ISO/IEC Guide 98-3 will be published as a re-issue of the Guide to the expression of uncertainty in measurement
(GUM), 1995.
2 © ISO 2008 – All rights reserved

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SIST EN ISO 10846-1:2008
ISO 10846-1:2008(E)
3.7
dynamic transfer stiffness
k
2,1
frequency-dependent ratio of the blocking force phasor F on the output side of a resilient element to the
2,b
displacement phasor u on the input side
1
=/F u
k
2,1
2,b
1
NOTE 1 The subscripts “1”and “2” denote the input and output sides, respectively.
NOTE 2 The value of k can be dependent on the static preload, temperature and other conditions.
2,1
NOTE 3 At low frequencies, k is mainly determined by elastic and dissipative forces and kk≈ . At higher
1,1 2,1
2,1
frequencies, inertial forces in the resilient element play a role as well and kk≠ .
1,1 2,1
3.8
loss factor of resilient element
h
ratio of the imaginary part of k to the real part of k , i.e. tangent of the phase angle of k , in the low-
2,1 2,1 2,1
frequency range where inertial forces in the element are negligible
3.9
point contact
contact area which vibrates as the surface of a rigid body
3.10
linearity
property of the dynamic behaviour of a resilient element, if it satisfies the principle of superposition
NOTE 1 The principle of superposition can be stated as follows: if an input x (t) produces an output y (t) and in a
1 1
separate test an input x (t) produces an output y (t), superposition holds if the input a x (t) + b x (t) produces the output
2 2 1 2
ay (t) + b y (t). This must hold for all values of a, b and x (t), x (t); a and b are arbitrary constants.
1 2 1 2
NOTE 2 In practice, the above test for linearity is impractical and a limited check of linearity is performed by measuring
the dynamic transfer stiffness for a range of input levels. For a specific preload, if the dynamic transfer stiffness is
nominally invariant, the system can be considered linear. In effect, this procedure checks for a proportional relationship
between the response and the excitation.
3.11
direct method
method in which either the input displacement, velocity or acceleration and the blocking output force are
measured
3.12
indirect method
method in which the vibration transmissibility (for displacement, velocity or acceleration) of a resilient element
is measured, with the output loaded by a compact body of known mass
NOTE The term “indirect method” can be permitted to include loads of any known impedance other than a mass-like
impedance. However, the ISO 10846 series does not cover such methods.
3.13
driving point method
method in which either the input displacement, velocity or acceleration and the input force are measured, with
the output side of the resilient element blocked
3.14
flanking transmission
forces and accelerations at the output side caused by the vibration exciter on the input side but via
transmission paths other than through the resilient element under test
© ISO 2008 – All rights reserved 3

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SIST EN ISO 10846-1:2008
ISO 10846-1:2008(E)
3.15
upper limiting frequency
f
UL
frequency up to which results for k are valid, according to the criteria given in various parts of ISO 10846
1,2
4 Selection of appropriate International Standard
Table 1 provides guidance for the selection of the appropriate part of ISO 10846.
Table 1 — Guidance for selection
International Standard and method type
ISO 10846-4 ISO 10846-5

ISO 10846-2 ISO 10846-3
Direct or indirect Driving point
Direct method Indirect method
method method
Type of resilient support support other than support support
element
Examples resilient mountings for instruments, equipment, bellows, hoses, see under ISO 10846-2
machinery and buildings resilient shaft and ISO 10846-3
couplings, power
supply cables
Frequency range 1 Hz to f f to f Direct method: see 1 Hz to f
UL 2 3 UL
of validity under ISO 10846-2;
f dependent on test rig; f typically (but not f typically (but not
UL 2 UL
typically (but not limited limited to) between Indirect method: see limited to) < 200 Hz
to) 300 Hz < f < 500 Hz 20 Hz and 50 Hz. For under ISO 10846-3
UL
f is dependent both on

UL
very stiff mountings
test rig and on test
f > 100 Hz.
2
element properties;
f typically 2 kHz to
3
5 kHz, but dependent
on the test rig
Translational 1, 2 or 3 1, 2 or 3 1, 2 or 3 1, 2 or 3
components
Rotational none informative annex informative annex none
components
4 dB 4 dB
Expanded To be estimated To be estimated
measurement according to according to
(considered as the (considered as the
uncertainty for ISO/IEC Guide 98-3 ISO/IEC Guide 98-3
upper limit) upper limit)
95 % coverage
probability
NOTE Within coinciding frequency ranges of validity, and within the uncertainty ranges of the methods, the direct method, the
indirect method and the driving point method yield the same result.

Further guidance is given in Clauses 5 and 6.
5 Theoretical background
5.1 Dynamic transfer stiffness
This clause explains why the dynamic transfer stiffness is most appropriate to characterize the vibro-acoustic
transfer properties of resilient elements for many practical applications. It also describes special situations
where other vibro-acoustic properties, not covered in ISO 10846, would also be necessary.
4 © ISO 2008 – All rights reserved

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SIST EN ISO 10846-1:2008
ISO 10846-1:2008(E)
The dynamic transfer stiffness, as defined in 3.7, is determined by the elastic, inertia and damping properties
of the resilient element. Describing the test results in terms of stiffness properties allows for compliance with
data of static and/or low-frequency dynamic stiffness, which are commonly used. The additional importance of
inertial forces (i.e. elastic wave effects in the isolators) makes the dynamic transfer stiffness at high
frequencies more complex than at low frequencies. At low frequencies, only elastic and damping forces are
important. Because in general the modulus of elasticity and the damping properties are only weakly
dependent on frequency in this range, this holds also for the low-frequency dynamic stiffness.
NOTE For many resilient elements, static stiffness and low-frequency dynamic transfer stiffness are different.
In principle, the dynamic transfer stiffness of vibro-acoustic resilient elements is dependent on static preload,
temperature and relative humidity. In the following theory, linearity, as defined in 3.10, is assumed. See
Annex D for further information.
Relationships between the dynamic transfer stiffness and other quantities are listed in Annex A. These
relationships imply that, for the actual performance of the tests, only practical considerations will determine
whether displacements, velocities or accelerations are measured. However, for presentation of the results in
agreement with the other parts of ISO 10846, appropriate conversions may be needed.
5.2 Dynamic stiffness matrix of resilient elements
5.2.1 General concept
A familiar approach to the analysis of complex vibratory systems is the use of stiffness – compliance – or
transmission matrix concepts. The matrix elements are basically special forms of frequency-response
functions; they describe linear properties of mechanical and acoustical systems. On the basis of the
knowledge of the individual subsystem properties, corresponding properties of assemblies of subsystems can
be calculated. The three matrix forms mentioned above are interrelated and can be readily transformed
[5]
amongst themselves . However, only stiffness-type quantities are specified in ISO 10846 for the
experimental characterization of resilient elements under static preload.
The general conceptual framework for the specified characterization of resilient elements is shown in Figure 1.

Figure 1 — Block diagram of source/isolators/receiver system
The system consists of three blocks, which respectively represent the vibration source, a number n of isolators
and the receiving structures. A point contact is assumed at each connection between source and isolator and
between isolator and receiver. To each connection point, a force vector F containing three orthogonal forces
3)
and three orthogonal moments and a displacement vector u containing three orthogonal translational
components and three orthogonal rotational components are assigned. In Figure 1, just one component of
each of the vectors F , u , F and u is shown. These vectors contain 6n elements, where n denotes the
1 1 2 2
number of isolators.
To show that the blocked transfer stiffness, defined in 3.7 as dynamic transfer stiffness, is suitable for isolator
characterization in many practical cases, the discussion will proceed from the simplest case of unidirectional
vibration to the multidirectional case for a single isolator.

3) Linear algebra: a vector is a linear array of elements.
© ISO 2008 – All rights reserved 5

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SIST EN ISO 10846-1:2008
ISO 10846-1:2008(E)
5.2.2 Single isolator, single vibration direction
For unidirectional vibration of a single vibration isolator, the isolator equilibrium may be expressed by the
following stiffness equations:
F = k u + k u (1)
1 1,1 1 1,2 2
F = k u + k u (2)
2 2,1 1 2,2 2
where
k and k are driving point stiffnesses when the isolator is blocked at the opposite side (i.e. u = 0,
1,1 2,2 2
u = 0, respectively);
1
k and k are blocked transfer stiffnesses, i.e. they denote the ratio between the force on the
1,2 2,1
blocked side and the displacement on the driven side. k = k for passive isolators,
1,2 2,1
because passive linear isolators are reciprocal.
Due to increasing inertial forces, k and k become different at higher frequencies. At low frequencies, only
1,1 2,2
elastic and damping forces play a role, making all k equal.
i,j
NOTE 1 These equations are for single frequencies. F and u are phasors and k are complex quantities.
i i i,j
The matrix form of Equations (1) and (2) is
F = Ku (3)
with the dynamic stiffness matrix
⎡⎤kk
1,1 1,2
K= (4)
⎢⎥
kk
2,1 2,2
⎣⎦
For excitation of the receiving structure via the isolator
F
2
k= − (5)
t
u
2
where k denotes the dynamic driving point stiffness of the termination. The minus sign is a consequence of
t
the convention adopted in Figure 1.
From Equations (2) and (5) it follows that
k
2,1
F = u (6)
2
1
k
2,2
1 +
k
t
Therefore, for a given source displacement u , the force F depends both on the isolator driving point dynamic
1 2
stiffness and on the receiver driving point dynamic stiffness. However, if |k | < 0,1|k |, then F approximates
...

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