ISO 18437-4:2008
(Main)Mechanical vibration and shock — Characterization of the dynamic mechanical properties of visco-elastic materials — Part 4: Dynamic stiffness method
Mechanical vibration and shock — Characterization of the dynamic mechanical properties of visco-elastic materials — Part 4: Dynamic stiffness method
ISO 18437-4:2008 specifies a direct method for measuring the complex dynamic moduli of elasticity (the Young, shear and bulk moduli, and their respective loss factors corresponding to the tensile, shear and all compressive strains) for polymeric (rubbery and viscous polymers, as well as rigid plastics) materials over a wide frequency and temperature range. Measurements are performed by the dynamic stiffness method, which uses electric signals from sensors attached to a test piece. These signals are proportional to the dynamic forces acting on the test piece and the strains in the test piece due to the effect of these forces. The measurement frequency range is determined by the size of test piece, the accuracy required on the dynamic modulus measurements, the relationship between the stiffness of the oscillation generator and the stiffness of the test piece, and by the resonance characteristics of the test fixture used. The method presented in ISO 18437-4:2008 allows measurement under any static pre-load allowed for the test piece (including the test piece having the non-linear characteristics under different static loads), but under small dynamic (acoustic) strains, i.e. in limits where the linear properties of the test piece are not distorted. Depending on the pre-load conditions, the relation between the moduli is unique.
Vibrations et chocs mécaniques — Caractérisation des propriétés mécaniques dynamiques des matériaux visco-élastiques — Partie 4: Méthode de la raideur dynamique
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 18437-4
First edition
2008-06-01
Mechanical vibration and shock —
Characterization of the dynamic
mechanical properties of visco-elastic
materials —
Part 4:
Dynamic stiffness method
Vibrations et chocs mécaniques — Caractérisation des propriétés
mécaniques dynamiques des matériaux visco-élastiques —
Partie 4: Méthode de la raideur dynamique
Reference number
©
ISO 2008
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ii © ISO 2008 – All rights reserved
Contents Page
Foreword. iv
Introduction . v
1 Scope .1
2 Normative references .1
3 Terms and definitions .2
4 Principle.4
5 Equipment .5
5.1 Hardware.5
5.2 Set-up.5
6 Recommended set-up for applying the different types of strain to the test piece and
calculation of quotients, α .9
E,G,K
6.1 Choosing test piece size.9
6.2 Rigid plastics.9
6.3 Rubbery materials.10
6.4 Viscous materials .11
6.5 Bulk modulus of all materials.13
7 Test pieces .13
7.1 Choosing the shape and size of the test piece.13
7.2 Instructions for manufacturing and preparing test pieces .14
8 Conditioning.16
8.1 Storage.16
8.2 Temperature .16
8.3 Mechanical conditioning.16
8.4 Humidity conditioning.16
8.5 Measurement conditioning .16
9 Main error sources.17
10 Measurement results and processing .17
10.1 Frequency-temperature superposition.17
10.2 Data presentation.18
10.3 Test report .19
Bibliography .20
Foreword
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(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
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Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
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ISO 18437-4 was prepared by Technical Committee ISO/TC 108, Mechanical vibration, shock and condition
monitoring.
ISO 18437 consists of the following parts, under the general title Mechanical vibration and shock —
Characterization of the dynamic mechanical properties of visco-elastic materials:
⎯ Part 2: Resonance method
⎯ Part 3: Cantilever shear beam method
⎯ Part 4: Dynamic stiffness method
The following parts are under preparation:
⎯ Part 1: Principles and guidelines
⎯ Part 5: Poisson's ratio based on finite element analysis
iv © ISO 2008 – All rights reserved
Introduction
Visco-elastic materials are used extensively to reduce vibration magnitudes, of the order of hertz to kilohertz,
in structural systems through dissipation of energy (damping) or isolation of components, and in acoustical
applications that require modification of the reflection, transmission, or absorption of energy. The design,
modelling and characterization of such systems often require specific dynamic mechanical properties (the
Young, shear, and bulk moduli and their corresponding loss factors) in order to function in an optimum
manner. Energy dissipation is due to interactions on the molecular scale and can be measured in terms of the
lag between stress and strain in the material. The visco-elastic properties (modulus and loss factor) of most
materials depend on frequency, temperature, and strain amplitude. The choice of a specific material for a
given application determines the system performance. The goal of this part of ISO 18437 is to provide details,
in principle, of the operation of the direct dynamic stiffness method, the measurement equipment used in
performing the measurements, and the analysis of the resultant data. A further aim is to assist users of this
method and to provide uniformity in the use of this method. This part of ISO 18437 applies to the linear
behaviour observed at small strain amplitudes, although the static stiffness may be non-linear.
INTERNATIONAL STANDARD ISO 18437-4:2008(E)
Mechanical vibration and shock — Characterization of the
dynamic mechanical properties of visco-elastic materials —
Part 4:
Dynamic stiffness method
1 Scope
This part of ISO 18437 specifies a direct method for measuring the complex dynamic moduli of elasticity (the
Young, shear and bulk moduli, and their respective loss factors corresponding to the tensile, shear and all
compressive strains) for polymeric (rubbery and viscous polymers, as well as rigid plastics) materials over a
wide frequency and temperature range. Measurements are performed by the dynamic stiffness method, which
uses electric signals from sensors attached to a test piece. These signals are proportional to the dynamic
forces acting on the test piece and the strains in the test piece due to the effect of these forces.
The measurement frequency range is determined by the size of test piece, the accuracy required on the
dynamic modulus measurements, the relationship between the stiffness of the oscillation generator and the
stiffness of the test piece, and by the resonance characteristics of the test fixture used.
The method presented in this part of ISO 18437 allows measurement under any static pre-load allowed for the
test piece (including the test piece having the non-linear characteristics under different static loads), but under
small dynamic (acoustic) strains, i.e., in limits where the linear properties of the test piece are not distorted.
Depending on the pre-load conditions, the relation between the moduli is unique.
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 472, Plastics — Vocabulary
ISO 483, Plastics — Small enclosures for conditioning and testing using aqueous solutions to maintain the
humidity at a constant value
ISO 2041, Mechanical vibration, shock and condition monitoring — Vocabulary
ISO 4664-1, Rubber, vulcanized or thermoplastic — Determination of dynamic properties — Part 1: General
guidance
ISO 6721-1, Plastics —Determination of dynamic mechanical properties — Part 1: General principles
ISO 6721-4, Plastics — Determination of dynamic mechanical properties — Part 4: Tensile vibration — Non-
resonance method
ISO 6721-6, Plastics — Determination of dynamic mechanical properties — Part 6: Shear vibration — Non-
resonance method
ISO 10112, Damping materials — Graphical presentation of the complex modulus
ISO 10846-1, Acoustics and vibration — Laboratory measurement of vibro-acoustic transfer properties of
resilient elements — Part 1: Principles and guidelines
ISO 23529, Rubber — General procedures for preparing and conditioning test pieces for physical test
methods
NOTE ISO 10846-1 is concerned with the global measurement of dynamic input and transfer stiffness and
mechanical resistance of resilient fixtures. This part of ISO 18437 is concerned with the characterization of the dynamic
Young modulus, shear modulus, bulk modulus, and corresponding loss factors of the visco-elastic materials that are used
in the fixtures.
3 Terms and definitions
For the purposes of this part of ISO 18437, the terms and definitions given in ISO 472, ISO 483, ISO 2041,
ISO 4664-1, ISO 6721-1, ISO 6721-4, ISO 6721-6, ISO 10112, ISO 10846-1, ISO 23529, and the following
apply.
3.1
dynamic mechanical properties
〈visco-elastic materials〉 fundamental elastic properties, i.e., elastic modulus, shear modulus, bulk modulus
and loss factor
3.2
damped structure
structure containing elements made from damping materials
3.3
Young modulus
modulus of elasticity
E
ratio of the normal stress to linear strain
[9]
NOTE 1 Adapted from ISO 80000-4-18.1:2006 .
NOTE 2 The Young modulus is expressed in pascals.
NOTE 3 The complex Young modulus, E*, for a visco-elastic material is represented by E* = E′ + iE″, where E′ is the
real (elastic) component of the Young modulus and E″ is the imaginary (loss modulus) component of the Young modulus.
The real component represents elastically stored mechanical energy, while the imaginary component is a measure of
mechanical energy loss.
3.4
shear modulus
modulus of rigidity
Coulomb modulus
G
ratio of the shear stress to the shear strain
[9]
NOTE 1 Adapted from ISO 80000-4-18.2:2006 .
NOTE 2 The shear modulus is expressed in pascals.
NOTE 3
...
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