EN ISO 6721-3:1996

Plastics - Determination of dynamic mechanical properties - Part 3: Flexural vibration - Resonance-curve method (ISO 6721-3:1994, including Technical Corrigendum 1: 1995)

Specifies a bending-vibration method based upon resonance curves for determining the flexural complex modulus of homogeneous plastics and the damping properties of laminated plastics intended for acoustic insulation.

Kunststoffe - Bestimmung dynamisch-mechanischer Eigenschaften - Teil 3: Biegeschwingung - Resonanzkurven-Verfahren (ISO 6721-3:1994, einschließlich Technische Korrektur 1:1995)

Dieser Teil von ISO 6721 legt ein Biegeschwingverfahren fest, bei dem mit Hilfe von Resonanzkurven der komplexe Biegemodul Ef von homogenen Kunststoffen und die Dämpfung von geschichteten Systemen bestimmt werden, die für akustische Isolation vorgesehen sind. Dies sind beispielsweise Systeme aus Metallblech mit dämpfendem Kunststoffbelag oder Verbundsysteme, die aus zwei Metallblechen mit einer Kunststoffzwischenschicht bestehen. Für viele Zwecke ist es vorteilhaft, diese Eigenschaften als Funktion von Temperatur und Frequenz zu bestimmen.

Plastiques - Détermination des propriétés mécaniques dynamiques - Partie 3: Vibration en flexion - Méthode en résonance (ISO 6721-3:1994, Rectificatif Technique 1:1995 inclus)

La présente partie de l'ISO 6721 prescrit une méthode de vibration en flexion basée sur les courbes de résonance pour la détermination du module complexe en flexion E*fde plastiques homogènes et des propriétés d'amortissement de plastiques stratifiés spécialement destinés à l'isolation acoustique, par exemple des systèmes consistant en une feuille métallique revêtue d'une couche de plastique amortissant ou des systèmes en sandwichs consistant en deux feuilles métalliques avec une couche intermédiaire en plastique; pour beaucoup d'usages, il est utile de déterminer ces propriétés en fonction de la température et de la fréquence.

Polimerni materiali – Določevanje dinamičnih mehanskih lastnosti – 3. del: Upogibne vibracije – Metoda resonančne krivulje (ISO 6721-3:1994, vključno s tehničnim popravkom 1: 1995)

General Information

• Status: Withdrawn
• Publication Date: 20-Feb-1996
• Withdrawal Date: 02-Mar-2021
• ICS: 83.080.01 - Plastics in general
• Technical Committee: CEN/TC 249 - Plastics
• Drafting Committee: CEN/TC 249/SC 1/WG 3 - Mechanical properties and preparation of test specimens
• Current Stage: 9960 - Withdrawal effective - Withdrawal
• Completion Date: 03-Mar-2021
• Ref Project: SIST EN ISO 6721-3:1999 - Plastics - Determination of dynamic mechanical properties - Part 3: Flexural vibration - Resonance-curve method (ISO 6721-3:1994, including Technical Corrigendum 1: 1995)

Relations

• Replaced By: EN ISO 6721-3:2021 - Plastics - Determination of dynamic mechanical properties - Part 3: Flexural vibration - Resonance-curve method (ISO 6721-3:2021)
• Effective Date: 10-Mar-2021

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-1999
3ROLPHUQLPDWHULDOL±'RORþHYDQMHGLQDPLþQLKPHKDQVNLKODVWQRVWL±GHO
8SRJLEQHYLEUDFLMH±0HWRGDUHVRQDQþQHNULYXOMH,62YNOMXþQRV
WHKQLþQLPSRSUDYNRP
Plastics - Determination of dynamic mechanical properties - Part 3: Flexural vibration -
Resonance-curve method (ISO 6721-3:1994, including Technical Corrigendum 1: 1995)
Kunststoffe - Bestimmung dynamisch-mechanischer Eigenschaften - Teil 3:
Biegeschwingung - Resonanzkurven-Verfahren (ISO 6721-3:1994, einschließlich
Technische Korrektur 1:1995)
Plastiques - Détermination des propriétés mécaniques dynamiques - Partie 3: Vibration
en flexion - Méthode en résonance (ISO 6721-3:1994, Rectificatif Technique 1:1995
inclus)
Ta slovenski standard je istoveten z: EN ISO 6721-3:1996
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL
ISO
STANDARD 6721-3
First edition
1994-11-01
Plastics - Determination of dynamic
mechanical properties -
Part 3:
- Resonance-curve method
Flexural Vibration
Plas tiques - Determination des propriktks mkaniques dynamiques -
Partie 3: Vibration en flexion - Methode en ksonance
Reference number
ISO 6721-3:1994(E)
ISO 6721=3:1994(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. Esch 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.
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.
International Standard ISO 6721-3 was prepared by Technical Committee
lSO/TC 61, Plastics, Subcommittee SC 2, Mechanical properties.
Together with ISO 6721-1, it cancels and replaces ISO 6721:1983, which
has been technically revised.
ISO 6721 consists of the following Parts, under the general title
Plas tics - Determination of dynamic mechanical properties:
- Part 7: General principles
- Part 2: Torsion-pendulum method
- Part 3: Flexural vibra tion - Resonance-curve method
- Part 4: Tensile Vibration - Non-resonance method
- Part 5: Flexural Vibration - Non-resonance method
- Part 6: Shear Vibration - Non-resonance method
- Part 7: Torsional Vibration - Non-resonance me thod
Annexes A and B of this part of ISO 6721 are for information only.
0 ISO 1994
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronrc or mechanical, inciuding photocopyrng and
microfilm, without permission In writing from the publisher.
lnternational Org anization fo r Standa rdization
20 l Switzerland
Case Postale 56 l CH-121 Geneve
Printed in Switzerland
ii
INTERNATIONAL STANDARD 0 ISO ISO 6721=3:1994(E)
- Determination of dynamic mechanical
Plastics
properties -
Part 3:
- Resonance-curve method
Flexural Vibration
NOTE 1 As stated in ISO 6721-1, frequencies derived
1 Scope
from resonance curves based on deformation-rate ampli-
tude measurements tan be exactly related to dynamic
This part of ISO 6721 specifies a bending-Vibration
properties. For the recommended range of the loss factor
method based upon resonance curves for determining
of this part of the International Standard, i.e. tan 6 < O,l,
the flexural complex modulus J!!?; of homogeneous
resonance curves based upon deformation amplitudes tan
plastics and the damping properties of laminated
also be used. For highly damping materials, see
ISO 6721-1 :1994, annex A.
plastics intended for acoustic insulation, for example
Systems consisting of a metal sheet coated with a
damping plastic layer, or sandwich Systems consisting
4 Principle
of two sheet-metal layers with an intermediate plastic
layer. For many purposes, it is useful to determine
A specimen is submitted to forced bending vibrations
these properties as a function of temperature and
in the frequency range between about 10 Hz and
frequency.
The
1 000 Hz. resonance curve (see
ISO 6721-1:1994, subclause 3.11) is determined and,
from the curve obtained, the flexural storage modulus
2 Normative reference
E ’, (see ISO 6721-1 :1994, subclause 3.2) is calculated
in the range above 0,5 MPa and the loss factor given
The following Standard contains provisions which,
by tan 6 = E ”,IE ’, (see ISO 6721-1 :1994, subclause
through reference in this text, constitute provisions
3.6) is calculated in the range between about 1 O-*
of this part of ISO 6721. At the time of publication, the
and IO-’ (see note 1). The test frequency tan be
edition indicated was valid. All Standards are subject
varied by making measurements at more than one
to revision, and Parties to agreements based on this
vibrational Order. The measurement range for the
part of ISO 6721 are encouraged to investigate the
flexural loss modulus E ”, (see ISO 6721-1 :1994, sub-
possibility of applying the most recent edition of the
clause 3.3) is determined by that of the loss factor and
Standard indicated below. Members of IEC and ISO
by the value of the storage modulus.
maintain registers of currently valid International
Standards.
The mode of oscillation used is designated oscillation
mode Ill (see ISO 6721-1:1994, table 2) and the type
ISO 6721-1 :1994, Plastics - Determination of dy-
of modulus measured is designated Ef (see
namic mechanical properties - Part 1: General prin-
ISO 6721-1:1994, table 3).
ciples.
The test is performed on rectangular bars, either
mounted vertically with the upper end clamped and
the other end free (method A) or suspended horizon-
3 Definitions
tally by fine fibres at vibrational nodes (method B) (see
figure 1). Method A is suitable for testing specimens
See ISO 6721-1:1994, clause 3.

0 ISO
ISO 6721=3:1994(E)
of most types of plastic, including relatively soft ma- 5.3 Exciter and detector
terials, whereas method B is particularly suitable for
testing rigid (i.e. dimensionally stable) specimens, for The frequency generator shall be capable of exciting
example sheet metal covered by a plastic layer for the specimen with the aid of the electromagnetic
transducer to oscillations within the frequency range
damping purposes.
of 10 Hz to 1 000 Hz with a constant forte amplitude.
The detector shall be capable of measuring the de-
formation or deformation-rate amplitude (see note 1)
5 Test apparatus
of the specimen and the frequency of the oscillation,
thereby permitting the recording of the resonance
5.1 General
curve (see ISO 6721-1:1994, subclause 3.11 and an-
nex A).
The apparatus consists of devices for clamping
(method A) or suspending (method B) the specimen,
The amplitude of the exciter and the sensitivity of the
electronie devices (frequency generator and recording
detector shall not vary with frequency by more than
device) for exciting the specimen to forced bending
0,5 % within the range of a Single-resonance peak, i.e.
Vibration and for measuring the frequency as well as
for any 10 % Variation of the frequency.
the velocity ampiitude of the specimen (see note 1).
For excitation and detection of the vibrations two
A tracking filter shall be used to minimize noise at the
electromagnetic transducers are situated near the
detector. Frequencies shall be measured with a res-
ends of the specimen. The specimen, the clamping
olution of at least 0,l % (see 11.2).
or supporting device and the electromagnetic trans-
Two small, thin steel plates shall be adhesively
ducers are enclosed in a temperature-controlled
bonded at the ends of the specimen to permit the
chamber (see figure 1).
excitation and detection of the vibrations by means
of suitable electromagnetic transducers (see 6.2).
5.2 Clamps or Suspension fibres
If the specimen is clamped at one end, the clamp
5.4 Temperature-controlled enclosure
shall be designed to hold the upper end of the speci-
men securely and tightly [see figure 1 a)]. lt shall be
See ISO 6721-1 :1994, subclause 5.3.
constructed so that no additional damping of the sys-
tem occurs.
tional damping: 5.5 Gas supply
There are two Causes of addi
- Friction between the test specimen and the Supply of air or other suitable inert gas for purging
clamp: This tan be detected by stimulating freely purposes.
decaying oscillations of the relevant vibrational or-
der. As explained in ISO 6721-1 :1994, annex B,
the type of decay is indicative of different types
5.6 Temperature-measurement device
of deviation from linear viscoelastic behaviour.
See ISO 6721-1 :1994, subclause 5.5.
- Vibration of the clamp: The clamp shall be rigidly
mounted on a heavy mass, which acts as a
counterweight to the oscillating test specimen.
5.7 Devices for measuring test specimen
This requires a heavy rigid stand within the
dimensions and density
temperature-controlled chamber (see figure 1).
If the specimen is tested in the horizontal Position, it
See ISO 6721-1:1994, subclause 5.6.
shall be supported by two fine fibres at vibrational
The balance used for measuring the mass of the
nodes (see 9.3.2).
specimen shall be capable of weighing to 1 mg.

ISO 6721=3:1994(E)
il
Clamp
To amplifier
Temperature-controlled
-enclosure
From frequencygenerator
a) Method A
Temperature-controlled
enclosure
Vibrationalnodes
From frequencygenerator To amplifier
b) Method B
- Schematic diagrams of test apparatus for methods A and B
Figure 1
0 ISO
ISO 672%3:1994(E)
plastic material on steel sheet, the plastic may be ap-
6 Test specimens
plied to the metal by spraying, as a mastic or as an
adhesively bonded sheet.
See ISO 6721-1 :1994, clause 6.
7 Number
6.1 Shape and dimensions
See ISO 6721-1:1994, clause 7.
Spetimens shall be rectangular bars or Strips thick
enough to give sufficient bending stiffness, which is
critical for the resonance frequency. On the other
8 Conditioning
hand, the thickness shall be sufficiently small when
compared to the wavelength of the bending Vibration. See ISO 6721-1 :1994, clause 8.
The specimen thickness shall also be limited to avoid
effects due to shear deformation and rotatory inertia
9 Procedure
if accurate values of E’ are required. Length-to-
thickness ratios of less than 50 shall be avoided if
9.1 Test atmosphere
values of E’ are required to be accurate to within
+ 5 %, from measurements up to the sixth Order of
-
See ISO 6721-1:1994, subclause 9.1.
homogeneous, isotropic specimens.
The thickness of the layers of a multilayer System will
9.2 Measurement of specimen Cross-section
depend on the purpose for which the System was
and density
designed. When comparing various Systems by the
bending-Vibration test, the preferred ratio of the mass
See ISO 6721-1 :1994, subclause 9.2.
of the plastic layer to the mass of the basic sheet
material is 1:5. Determine the density of the specimen (i.e. the mass
of the free length per unit volume) to + 0,5 %.
-
The width of the specimens shall be less than one-
half of the wavelength used in Order to avoid lateral
9.3 Mounting the test specimens and
resonance vibrations. A width of 10 mm should be
adjustment of the tranducers
suitable in most cases.
The length of the specimens depends on the desired 9.3.1 Method A
frequency. For specimens clamped at one end, the
Clamp the specimen so that the clamping forte is
length shall be sufficiently large to avoid the clamp
high enough to avoid additional damping from friction
influencing the Vibration significantly. Usually a free
between the specimen and the clamp (see 5.2).
length of 180 mm will be suitable. If the specimen is
Measure the free length L of the specimen to
not clamped, its length shall be 150 mm.
+ 0,5 %.
-
6.2 Preparation
9.3.2 Method B
See ISO 6721-1 :1994, subclause 6.2.
Measure the length of the specimen to + 0,2 %. Cal-
-
culate the distance I+ of the first nodes from the ends
Small, thin, light steel plates shall be adhesively
of the specimen,
using one of the following two
bonded to the specimens near their ends to allow
equations:
excitation and detection of the vibrations by means
of electromagnetic transducers. To avoid errors in E’
Li/Z = 0,224 for i = 1 . . .
(1)
greater than 4 %, the ratio of the added mass to the
Li/l = 0,660/(2i + 1) for i > 1 . . .
specimen mass shall not exceed 1 %. To avoid the (2)
steel plates causing additional stiffness, they shall not
where
extend along more than 2 % of the length of the
specimen. The distance between the steel plates
1 is the length of the specimen;
shall be large enough to avoid Cross-talk between
exciter and detector. is the vibrational Order.
Multilayer specimens shall be fabricated with the Mount the specimen by fine, preferably non-metallic,
thickness and by the production techniques to be fibres at the calculated positions of the vibrational
used in the projected end-use. For example, for a nodes.
0 ISO ISO 6721=3:1994(E)
9.3.3 Adjustment of the transducers 1 length of the specimen (method B), expressed
in metres
After clamping or supporting the specimen, adjust the
L free length of the specimen (method A), ex-
detector and exciter transducers so that they are just
pressed in metres
far enough from the specimen to avoid any noticeable
effect on the resonance frequency. With the usual
h thickness of the specimen, expressed in me-
test apparatus, the recommended distance is greater
tres
than 3 mm for i
...