ISO 22762-1:2005

Elastomeric seismic-protection isolators - Part 1: Test methods

ISO 22762 applies to elastomeric seismic isolators used to provide buildings or bridges with protection from earthquake damage. The isolators covered consist of alternate elastomer layers and reinforcing steel plates. They are placed between a superstructure and its substructure to provide both flexibility for decoupling structural systems from ground motion, and damping capability to reduce displacement at the isolation interface and the transmission of energy from the ground into the structure at the isolation frequency. ISO 22762-1:2005 specifies the test methods for determination of the characteristics of elastomeric seismic isolators and for measurement of the properties of the rubber material used in their manufacture. The specifications cover testing for all properties required in the elastomeric isolators, such as compression and shear properties, the durability of the isolators and the physical properties of the materials used in isolators.

Appareils d'appuis structuraux en élastomère pour protection sismique — Partie 1: Méthodes d'essai

General Information

• Status: Withdrawn
• Publication Date: 21-Jul-2005
• Withdrawal Date: 21-Jul-2005
• ICS: 83.140.99 - Other rubber and plastics products
• Technical Committee: ISO/TC 45/SC 4 - Products (other than hoses)
• Drafting Committee: ISO/TC 45/SC 4/WG 9 - Elastomeric isolators
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 21-Oct-2010
• Completion Date: 13-Dec-2025

Relations

• Revised: ISO 22762-1:2010 - Elastomeric seismic-protection isolators - Part 1: Test methods
• Effective Date: 12-May-2008

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 22762-1
First edition
2005-07-15
Elastomeric seismic-protection
isolators —
Part 1:
Test methods
Appareils d'appuis structuraux en élastomère pour protection
sismique —
Partie 1: Méthodes d'essai
Reference number
©
ISO 2005
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©  ISO 2005
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ii © ISO 2005 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 2
4 Symbols and abbreviated terms. 4
5 Rubber material tests . 10
5.1 Test items. 10
5.2 Test conditions and test pieces . 10
5.3 Tensile properties . 10
5.4 Ageing test. 11
5.5 Hardness. 11
5.6 Adhesion. 11
5.7 Compression set . 11
5.8 Dynamic shear properties. 11
5.9 Fracture properties . 14
5.10 Brittleness point. 14
5.11 Ozone resistance . 14
5.12 Low temperature crystallization . 14
6 Isolator tests. 15
6.1 General. 15
6.2 Compression and shear stiffness tests. 15
6.3 Various dependence tests. 26
6.4 Ultimate shear properties. 39
6.5 Tensile testing . 41
6.6 Durability testing. 44
6.7 Reaction force due to low-rate deformation. 51
Annex A (normative) Determination of accelerated ageing conditions equivalent to expected life
at 23 °C . 54
Annex B (normative) Inertia force correction . 57
Annex C (normative) Friction force correction. 59
Annex D (normative) Determination of coefficient of linear thermal expansion . 62
Annex E (informative) Confirmation list . 64
Annex F (informative) Alternative methods of determining shear properties. 66
Annex G (informative) Creep test.68
Annex H (informative) Determination of reaction force due to low-rate deformation . 70
Annex I (informative) Durability investigation of elastomeric isolators used for 10 years in a
bridge . 72
Annex J (informative) Durability investigation of elastomeric isolators used for 7 years in a
building . 74
Bibliography . 78

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 22762-1 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee
SC 4, Products (other than hoses).
ISO 22762 consists of the following parts, under the general title Elastomeric seismic-protection isolators:
 Part 1: Test methods
 Part 2: Applications for bridges — Specifications
 Part 3: Applications for buildings — Specifications
iv © ISO 2005 – All rights reserved

Introduction
This International Standard contains two parts related to specifications for isolators — one for bridges and the
other for buildings — since the requirements for isolators for bridges and for buildings are quite different,
although the basic concept of the two products is similar. Therefore, when this International Standard is
applied to the design of bridge isolators, Part 2 and the relevant clauses in Part 1 are used and, when it is
applied to building isolators, Part 3 and the relevant clauses in Part 1 are used.
The main differences to be noted between isolators for bridges and isolators for buildings are as below:
a) Isolators for bridges are mainly rectangular in shape and those for buildings circular in shape.
b) Isolators for bridges are designed to be used for both rotation and horizontal displacement, while isolators
for buildings are designed for horizontal displacement only.
c) Isolators for bridges are designed to perform on a daily basis to accommodate length changes of bridges
caused by temperature changes as well as during earthquakes, while isolators for buildings are designed
to perform only during earthquakes.
d) Isolators for bridges are designed to withstand dynamic loads caused by vehicles on a daily basis as well
as earthquakes, while isolators for buildings are mainly designed to withstand dynamic loads caused by
earthquakes only.
For structures that are neither buildings nor bridges (e.g. tanks), the structural engineer may use either Part 2
or Part 3 of this International Standard, depending on the requirements of the structure.
INTERNATIONAL STANDARD ISO 22762-1:2005(E)

Elastomeric seismic-protection isolators —
Part 1:
Test methods
1 Scope
ISO 22762 applies to elastomeric seismic isolators used to provide buildings or bridges with protection from
earthquake damage. The isolators covered consist of alternate rubber layers and reinforcing steel plates.
They are placed between a superstructure and its substructure to provide both flexibility for decoupling
structural systems from ground motion, and damping capability to reduce displacement at the isolation
interface and the transmission of energy from the ground into the structure at the isolation frequency.
This part of ISO 22762 specifies the test methods for determination of the characteristics of elastomeric
seismic isolators and for measurement of the properties of the rubber material used in their manufacture.
The specifications cover testing for all properties required in the elastomeric isolators, such as compression
and shear properties, the durability of the isolators and the physical properties of the materials used in
isolators.
Annex E may be used to review those requirements needing confirmation prior to the test programme.
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 37, Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties
ISO 48, Rubber, vulcanized or thermoplastic — Determination of hardness (hardness between 10 IRHD and
100 IRHD)
ISO 188, Rubber, vulcanized or thermoplastic — Accelerated ageing and heat resistance tests
ISO 812, Rubber, vulcanized — Determination of low-temperature brittleness
ISO 813, Rubber, vulcanized or thermoplastic — Determination of adhesion to a rigid substrate — 90° peel
method
ISO 815, Rubber, vulcanized or thermoplastic — Determination of compression set at ambient, elevated or
low temperatures
ISO 1431-1, Rubber, vulcanized or thermoplastic — Resistance to ozone cracking — Part 1: Static and
dynamic strain testing
ISO 1827, Rubber, vulcanized or thermoplastic — Determination of modulus in shear or adhesion to rigid
plates — Quadruple shear method
ISO 3387, Rubber — Determination of crystallization effects by hardness measurements
ISO 4664-1, Rubber, vulcanized or thermoplastic — Determination of dynamic properties — Part 1: General
considerations
ISO 7500-1:2004, Metallic materials — Verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Verification and calibration of the force-measuring system
ISO 7619-2, Rubber, vulcanized or thermoplastic — Determination of indentation hardness — Part 2: IRHD
pocket meter method
ISO 11346:2004, Rubber, vulcanized or thermoplastic — Estimation of life-time and maximum temperature of
use
ISO 22762-2, Elastomeric seismic-protection isolators — Part 2: Applications for bridges — Specifications
ISO 22762-3, Elastomeric seismic-protection isolators — Part 3: Applications for buildings — Specifications
ISO 23529, Rubber — General procedures for preparing and conditioning test pieces for physical test
methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
breaking
rupture of elastomeric isolator due to compression (or tension)-shear loading
3.2
buckling
state when elastomeric isolators lose their stability under compression-shear loading
3.3
compressive properties of elastomeric isolator
compressive stiffness (K ) for all types of rubber bearings
v
3.4
compressive-shear testing machine
machine used to test elastomeric isolators, which has the capability of shear loading under constant
compressive load
3.5
cover rubber
rubber wrapped around the outside of inner rubber and reinforcing steel plates before or after curing of
elastomeric isolators for the purpose of protecting the inner rubber from deterioration due to oxygen, ultraviolet
rays and other natural elements and protecting the reinforcing plates from corrosion
3.6
design compressive stress
long term compressive force on the elastomeric isolator imposed by the structure
3.7
effective loaded area
area sustaining vertical load in elastomeric isolators, which corresponds to the area of reinforcing steel plates
2 © ISO 2005 – All rights reserved

3.8
effective width
〈rectangular elastomeric isolator〉 the smaller of the two side lengths of inner rubber to which direction shear
displacement is not restricted
3.9
elastomeric isolator
rubber bearing, for seismic isolation of buildings, bridges and other structures, which consists of multi-layered
vulcanized rubber sheets and reinforcing steel plates
NOTE Types of such isolators include high-damping rubber bearings, linear natural rubber bearings and lead rubber
bearings.
3.10
first shape factor
ratio of effectively loaded area to free deformation area of one inner rubber layer between steel plates
3.11
high-damping rubber bearing
HDR
elastomeric isolator with relatively high damping properties obtained by special compounding of the rubber
and the use of additives
3.12
inner rubber
rubber between multi-layered steel plates inside an elastomeric isolator
3.13
lead rubber bearing
LRB
elastomeric isolator whose inner rubber with a lead plug or lead plugs press fitted into a hole or holes of the
isolator body to achieve damping properties
3.14
linear natural rubber bearing
LNR
elastomeric isolator with linear shear force-deflection characteristics and relatively low damping properties and
fabricated using natural rubber
NOTE Any bearing with relatively low damping may be treated as an LNR bearing for the purposes of isolator testing.
3.15
maximum compressive stress
maximum compressive stress acting briefly on elastomeric isolators during an earthquake
3.16
nominal compressive stress
long-term compressive stress recommended by the manufacturer for the isolator, including the safety margin
3.17
roll-out
instability of an isolator with either dowelled or recessed connection under shear displacement
3.18
routine test
a test for quality control of the production isolators during and after manufacturing
3.19
second shape factor
〈circular elastomeric isolator〉 ratio of the diameter of the inner rubber to the total thickness of the inner rubber
〈rectangular or square elastomeric isolator〉 ratio of the effective width of the inner rubber to the total thickness
of the inner rubber
3.20
shear properties of elastomeric isolators
a comprehensive term that covers characteristics determined from isolator tests:
 shear stiffness (K ) for LNR;
h
 shear stiffness (K ) and equivalent damping ratio (h ) for HDR and LRB;
h eq
 post-yield stiffness (K ) and characteristic strength (Q ) for LRB.
d d
3.21
structural engineer
engineer who is in charge of designing of structure for base-isolated bridges or buildings and is responsible for
specifying the requirements for elastomeric isolators
3.22
type test
test for verification either of material properties and isolator performances during development of the product
or that project design parameters are achieved
3.23
ultimate properties
properties at either buckling, breaking, or roll-out of an isolator under compression-shear loading
3.24
ultimate property diagram
UPD
diagram giving the interaction curve of compressive stress and buckling strain or breaking strain of an
elastomeric isolator
4 Symbols and abbreviated terms
For the purposes of all three parts of ISO 22762, the symbols given in Table 1 apply.
Table 1 — Symbols and definitions
Symbol Definition
A effective plan area; plan area of elastomeric isolator excluding cover rubber portion
A
effective area of bolt
b
A overlap area between the top and bottom elastomer area of isolator sheared under non-seismic
e
displacement
A
load-free area of isolator
free
A
loaded area of isolator
load
A
p area of the lead plug for a lead rubber bearing
4 © ISO 2005 – All rights reserved

a
side length of square elastomeric isolator excluding cover rubber thickness, or length in
longitudinal direction of rectangular isolator excluding cover rubber thickness
a length of the shorter side of the rectangular isolator including cover rubber thickness
e
a' length in longitudinal direction of the rectangular isolator, including cover rubber thickness
B effective width for bending of flange
b length in transverse direction of the rectangular isolator, excluding cover rubber thickness
b' length in transverse direction of the rectangular isolator, including cover rubber thickness
c
distance from centre of bolt hole to effective flange section
D' outer diameter of circular isolator, including cover rubber
D
diameter of flange
f
d
inner diameter of reinforcing steel plate
i
d
diameter of bolt hole
k
d
outer diameter of reinforcing steel plate
o
E
ap apparent Young’s modulus of bonded rubber layer
E
apparent Young’s modulus corrected, if necessary, by allowing for compressibility
c
s
apparent Young’s modulus corrected for bulk compressibility depending on its shape factor (S )
E
c
E
bulk modulus of rubber
∞
E
Young’s modulus of rubber
F
tensile force on isolator by uplift
u
G
shear modulus
G γ equivalent linear shear modulus at shear strain γ
( )
eq
H height of elastomeric isolator including mounting flange
H
height of elastomeric isolator excluding mounting flange
n
h
eq equivalent damping ratio
h γ
( )
equivalent damping ratio as a function of shear strain
eq
K
post-yield stiffness (tangential stiffness after yielding of lead plug) of lead rubber bearing
d
K
shear stiffness
h
K
initial shear stiffness
i
K
p shear stiffness of lead plug inserted in lead rubber bearing
K
shear stiffness of lead rubber bearing before inserting lead plug
r
K
tangential shear stiffness
t
K
compressive stiffness
v
L
length of one side of a square flange
f
M resistance to rotation
M
moment acting on bolt
f
M
moment acting on isolator
r
n
number of rubber layers
n
number of fixing bolts
b
P compressive force
P
design compressive force
P
maximum design compressive force
max
P
minimum design compressive force
min
Q
shear force
Q
shear force at break
b
Q
shear force at buckling
buk
Q
characteristic strength
d
S
first shape factor
S
second shape factor
T temperature
T total rubber thickness, given by T = nt×
r r r
t
thickness of one rubber layer
r
tt,
thickness of rubber layer laminated on each side of plate
r1 r2
t
thickness of one reinforcing steel plate
s
t
thickness of outside cover rubber
o
U γ
( ) function giving ratio of characteristic strength to maximum shear force of a loop

V
uplift force
v
loading velocity
W
energy dissipated per cycle
d
X shear displacement
X
design shear displacement
X
shear displacement at break
b
X
shear displacement at buckling
buk
X
shear displacement due to quasi-static shear movement
s
X
maximum design shear displacement
max
X
shear displacement due to dynamic shear movement
d
Y compressive displacement
Z section modulus of flange
α
coefficient of linear thermal expansion

6 © ISO 2005 – All rights reserved

γ
shear strain
γ
design shear strain
γ
upper limit of the total of design strains on elastomeric isolators
a
γ
shear strain at break
b
γ
local shear strain due to compressive force
c
γ
shear strain due to dynamic shear movement
d
γ
maximum shear strain during earthquake
max
γ
local shear strain due to rotation
r
γ
shear strain due to quasi-static shear movement
s
γ
ultimate shear strain
u
δ
horizontal offset of isolator
H
δ
difference in isolator height measured between two points at opposite extremes of the isolator
V
ε
compressive strain of isolator
ε
creep strain
cr
ε
tensile strain of isolator
T
ε
tensile-break strain of isolator
Tb
ε
Ty tensile-yield strain of isolator
ζ
ratio of total rubber height to total height of rubber and steel layers
θ
rotation angle of isolator about the diameter of a circular bearing or about an axis through a
rectangular bearing
θ
rotation angle of isolator in the longitudinal direction (a)
a
θ
rotation angle of isolator in the transverse direction (b)
b
λ
correction factor for calculation of stress in reinforcing steel plates
η
correction factor for calculation of critical stress
κ correction factor for apparent Young’s modulus according to hardness
Σγ
total local shear strain
σ
compressive stress in isolator
σ
design compressive stress
σ
tensile stress in bolt
B
σ
bending stress in flange
b
σ
b allowable bending stress in steel
f
σ
critical stress in isolator
cr
σ
allowable tensile stress in steel
f
σ
maximum design compressive stress
max
σ
minimum design compressive stress
min
σ
for building: nominal long term compressive stress recommended by manufacturer
nom
σ
tensile stress in reinforcing steel plate
s
σ
allowable tensile stress in steel plate
sa
σ
sy yield stress of steel for flanges and reinforcing steel plates
σ
tensile strength of steel for flanges and reinforcing steel plates
su
σ
tensile stress
t
σ
allowable tensile stress in isolator
te
σ
yi yield stress in steel plate
τ
shear stress in bolt
B
τ
allowable shear stress in steel
f
φ
factor for computation of buckling stability
ψ
factor for computation of buckling check
ξ
factor for computation of critical stress

8 © ISO 2005 – All rights reserved

a) Circular type b) Rectangular type
(lhs of drawings shows LNR and HDR, rhs shows LRB) (lhs of drawings shows LNR and HDR, rhs shows LRB)

Key
1 cover rubber cured with insulator
2 cover rubber added after isolator cured
3 lead plug
Figure 1 — Cross-section of isolator
5 Rubber material tests
5.1 Test items
In order to assure the required quality of elastomeric isolators, it is necessary to specify the physical
properties of the rubber materials and the adhesion between the rubber and the steel plates. The basic
properties of rubber materials related to performance of elastomeric isolators are shown as test items in
Table 2.
Table 2 — Test items of rubber materials
Properties Test items Related standard(s)
Tensile properties Tensile strength ISO 37
Elongation at break
100 % modulus
Ageing properties Tensile strength ISO 188
Elongation at break ISO 37
100 % modulus
Hardness Hardness ISO 48
ISO 7619-2
Adhesion 90° peel strength between metal and rubber ISO 813
Classification of fracture mode
Compression set Compression set ISO 815
Shear properties Shear modulus ISO 4664-1
Equivalent damping ratio
Temperature dependence of shear modulus and
equivalent damping ratio
Repeated deformation dependence of shear modulus
and equivalent damping ratio
Fracture strength ISO 1827
Fracture strain
Brittleness point Brittleness temperature ISO 812
Inspection of deterioration
Ozone resistance ISO 1431-1 (static strain
(ozone cracking test on test)
vulcanized rubber)
Low temperature Hardness ISO 3387
crystallization
5.2 Test conditions and test pieces
The temperature and humidity in the laboratory, the preparation of test pieces, and methods for measuring
thickness and width, etc., shall be in accordance with ISO 23529.
Moulded test pieces shall be used. They shall be cured to have properties as similar as practicable to the
rubber in the bulk of the isolator.
5.3 Tensile properties
The tensile test should preferably be carried out by the method specified in ISO 37. However, the test piece
specified in Table 3 can be used.
10 © ISO 2005 – All rights reserved

Table 3 — Test piece dimensions
Dimensions in millimetres
Width of parallel-sided Length of parallel-sided Thickness of parallel- Distance between
section section sided section marked lines
5 ± 0,1 20 2,0 ± 0,2 20
5.4 Ageing test
5.4.1 Ageing properties of inner rubber
5.4.1.1 Anaerobic ageing
A set of ageing tests shall be performed on the inner rubber under anaerobic conditions as described in
Annex A. The properties monitored shall be either 100 % shear modulus and shear failure strain or the tensile
properties — 100 % modulus, tensile strength and elongation at break. From the results of these tests, the
activation energy is obtained based on the method specified in Annex A. Ageing conditions equivalent to the
expected lifetime (60 years or the period specified by the structural engineer) at 23 °C shall be determined
from this activation energy, and an ageing test shall then be performed for the properties monitored under
conditions equivalent to the expected lifetime.
5.4.1.2 Air ageing
An ageing test shall be performed on the inner rubber in accordance with the method specified in ISO 188,
monitoring the tensile strength and elongation at break. The test time and temperature shall be as specified in
ISO 22762-2 or ISO 22762-3.
5.4.2 Ageing properties of cover rubber
An ageing test shall be performed on the cover rubber in accordance with the method specified in ISO 188,
monitoring the tensile strength and elongation at break. The test time and temperature shall be as specified in
ISO 22762-2 or ISO 22762-3.
5.5 Hardness
Hardness shall be measured in accordance with the method specified in ISO 48 or ISO 7619-2.
5.6 Adhesion
An adhesion test shall be carried out as specified in ISO 813.
5.7 Compression set
Compression set shall be determined in accordance with the method specified in ISO 815. The test piece shall
be either a large-type or small-type cylindrical disc. Test conditions and requirements shall be as specified in
ISO 22762-2 or ISO 22762-3.
5.8 Dynamic shear properties
5.8.1 General
These tests shall be carried out as specified in ISO 4664-1, except for the test piece and analysis of test
results, in order to investigate the temperature, frequency, strain and repeated deformation dependence of the
shear modulus and equivalent damping ratio of rubber materials.
5.8.2 Test equipment
An apparatus as described in ISO 4664-1 which can measure vibration frequencies higher than 0,2 Hz and
shear strain amplitudes up to 400 % shall be used.
5.8.3 Test pieces
The shape and dimensions of the test pieces are different from those specified in ISO 4664-1. Use either test
piece specified below. Each test shall be performed on a previously unused test piece except when indicated
otherwise.
a) Two-block lap shear type
As shown in Figure 2, this test piece consists of two rubber blocks bonded to three plates of metal. The
size of one rubber block shall be 3,0 mm to 6,0 mm thick, 25 mm to 30 mm wide, and 25 mm to 30 mm
long for a square pillar, or 3,0 mm to 6,0 mm thick and 25 mm to 30 mm in diameter for a cylindrical disc.

Key
1 rubber
2 metal plate
Figure 2 — Two-block lap shear type

b) Four-block lap shear type
As shown in Figure 3, this test piece consists of four rubber blocks bonded to four plates of metal. The
size of one rubber block shall be 3,0 mm to 6,0 mm thick, 25 mm to 30 mm wide, and 25 mm to 30 mm
long for a square pillar, or 3,0 mm to 6,0 mm thick and 25 mm to 30 mm in diameter for a cylindrical disc.

Key
1 rubber
2 metal plate
Figure 3 — Four-block lap shear type
12 © ISO 2005 – All rights reserved

5.8.4 Test conditions
5.8.4.1 Test temperature
Test temperatures shall at least cover the range of service requirements. The values given in Table 4 shall be
included if they are within the service range. As a minimum requirement, tests shall be performed at one
frequency (0,2 Hz, 0,3 Hz or 0,5 Hz or the isolation frequency) and at one strain amplitude (100 %, 175 % or
the design shear strain). Tests at more than one temperature may be carried out using one test piece
provided that the tests are at one frequency and one strain amplitude, and that they are conducted in order of
decreasing temperature. The tolerance shall be ± 2 °C for all temperatures.
Table 4 — Test temperatures
Test temperature, °C 0 23 40
−20 −10
5.8.4.2 Frequency
The test frequencies shall be one of the sets given in Table 5, except that the isolation frequency, if known,
may replace the one closest to it in the table. If the dynamic property tests of the isolators are performed at a
lower frequency, this test shall also be carried out at that same frequency. As a minimum requirement, tests
shall be performed at 23 °C, and at one strain amplitude (100 %, 175 % or the design shear strain).
Tests at more than one frequency may be carried out using one test piece provided that the tests are at one
temperature and one strain amplitude, and that they are conducted in order of increasing frequency.
Table 5 — Vibration frequencies
Set 1 0,05 0,2 1,0
Vibration frequency, Hz Set 2 0,05 0,3 1,5
Set 3 0,1 0,5 2,0
5.8.4.3 Shear strain
The shear strains shall be selected from Table 6. The shear strains shown in Table 6 differ from those
specified in ISO 4664-1. It is recommended that the four ranges 5 %, 10 %, 50 %, and 100 % be selected
from them. The test strains shall range from 5 % to at least 1,5 × the design shear strain. As a minimum
requirement, tests shall be performed at one frequency (0,2 Hz, 0,3 Hz, 0,5 Hz or the isolation frequency) and
at 23 °C. One test piece may be used to cover a range of strains, provided that the strain intervals are at least
50 % or a factor of 2 whichever is the lower, the tests are at one temperature and one frequency and they are
carried out in order of increasing strain.
Table 6 — Shear strains
Shear strain, % ± 5 ± 10 ± 25 ± 50 ± 75 ± 100 ± 150 ± 175 ± 200 ± 250 ± 300 ± 350 ± 400

5.8.4.4 Number of cycles
The number of loading cycles shall be either 3 or 11 cycles, and should be consistent with that of isolator
tests.
5.8.5 Test results
The shear modulus and equivalent damping ratio shall be reported using the method specified in 6.2.2.6.
5.9 Fracture properties
A failure test shall be carried out as specified in ISO 1827. However, test pieces as specified in 5.8.3 shall be
used.
5.10 Brittleness point
A brittleness temperature test shall be carried out as specified in ISO 812.
5.11 Ozone resistance
An ozone resistance test shall be carried out as specified in ISO 1431-1 (static strain test).
5.12 Low temperature crystallization
For elastomers susceptible to low temperature crystallization (e.g. those compounds based on natural rubber,
polychloroprene and certain types of ethylene propylene), the resistance to this phenomenon shall be checked
by measuring the change in the hardness at low temperature, if the service temperature falls within the range
where crystallization may occur. Natural rubber shall be checked if the minimum service temperature T is
L
< 0 °C, and polychloroprene if the minimum service temperature T is < 5 °C.
L
The test shall be conducted in accordance with ISO 3387, except that the test temperature and the duration of
the test shall be as specified here, and a reading shall be taken after 3 h.
The duration and temperature of the test shall be set by the structural engineer in accordance with the service
conditions, except that the test temperature for natural rubber shall not be below −25 °C and for
polychloroprene not below −10 °C. The duration of the test at a particular temperature shall relate to the
period over which the minimum daily service temperature may be at or below that temperature. It is
recommended that, for natural rubber isolators, subjected to the service conditions in Table 7, where the time
is the cumulative total for which the isolators are exposed to the specified temperatures without the
temperature rising above +10 °C, a test shall be carried out for the time indicated at the test temperature
corresponding to the range of the minimum service temperature as indicated in Table 7.
Table 7 — Service and test conditions for natural rubber
Minimum temperature, T
L
−10 u T < 0 −20 u T < −10 T < −20
L L L
°C
t t t
Time, days
0 10 20
Test temperature, °C
−10 −20 −25
1,5t 1,5t + 0,1t 1,5t + 0,5t + 0,05t
Test period
0 10 0 20 10 0
The time and temperature of test for polychloroprene-based isolators shall be based on the service
temperature conditions defined in Table 8, where the time is the cumulative total for which the isolators are
exposed to the specified temperatures without the temperature rising above +10 °C. A test shall be carried out
for the time indicated at the test temperature corresponding to the range of the minimum service temperature
as indicated in Table 8.
14 © ISO 2005 – All rights reserved

Table 8 — Service and test conditions for chloroprene rubber
Minimum temperature, T
L
0 u T < 5 −5 u T < 0 T < −5
L L L
°C
t t t
Time, days
5 0 5
Test temperature, °C 0
−5 −10
1,5t 1,5t + 0,5t 1,5t + 0,5t + 0,25t
Test period
5 0 5 −5 0 5
NOTE Some elastomers are susceptible to crystallization if the ambient temperature is low over a prolonged period.
High-damping compounds of these elastomers may be more susceptible than conventional low-damping ones. The
crystallization process involves a nucleation period, during which little change in rubber stiffness occurs, followed by a
rapid stiffening as the crystallites grow. The nucleation period shortens as the temperature is lowered to that at which the
rate of crystallization is highest. The minimum test temperatures specified for natural rubber and polychloroprene are
those at which the rate of crystallization is highest. To ensure the performance of the isolator is not compromised, it is
necessary that the nucleation period is not much exceeded during any continuous exposure to low temperatures.
Crystallites melt when the ambient temperature of the isolators is raised sufficiently, and thus the effects are completely
reversible. If polychloroprene is used, crystallization resistant grades should be chosen where low temperature conditions
are to be encountered.
6 Isolator tests
6.1 General
In order to assure the required quality of elastomeric isolators, it is necessary to specify the functional
requirements. The basic properties of elastomeric isolators are shown as test items in Table 9.
When the same test piece is used for several tests, it shall be noted if the performance is influenced by
repetition.
NOTE Some of these properties may be determined using one of the standard test pieces detailed in Tables 10
and 11. The standard test piece is used for non-specific product testing, such as testing for the development of new
materials and products.
6.2 Compression and shear stiffness tests
6.2.1 Compression test
6.2.1.1 Principle
By measuring the compressive force and displacement, the compression stiffness and compression behaviour
of the elastomeric isolator can be determined.
6.2.1.2 Test machine
The machine shown schematically in Figure 4 shall be capable of compressing the elastomeric isolator under
controlled conditions. It shall also provide a method of measuring the compressive force and compressive
displacement to an accuracy of less than or equal to 1 % of the maximum values recorded. The force
calibration shall be based on ISO 7500-1. The machine shall maintain the parallelism of the upper and lower
loading platens for the test piece attachment during the test. A Class 1 machine as defined in Clause 7 of
ISO 7500-1:2004 is recommended.
In order to accurately measure the displacement of the elastomeric isolator, uniformly place two or more
compressive displacement gauges around the test piece (so that they may be at the same distance from the
test piece as shown in Figure 5). The average of those sensors shall be taken as a measurement value.
Table 9 — Test items for isolators
Properties Test items See Subclause
Compression properties Compression stiffness 6.2.1
Compression displacement
Shear properties Shear stiffness 6.2.2
Equivalent damping ratio
Post-yield stiffness
Characteristic strength
Dependency of shear 6.3.1
Shear strain dependency
properties
6.3.2
Compressive stress dependency
6.3.3
Frequency dependency
6.3.4
Repeated loading dependency
6.3.5
Temperature dependency
Dependency of 6.3.6
Shear strain dependency
compressive properties
6.3.7
Compressive stress dependency
Ultimate shear properties Breaking displacement (strain), force 6.4
Buckling displacement (strain), force
Roll-out displacement (strain), force
Tensile properties Tensile breaking force 6.5
Tensile yielding force
Shear strain
Durability Property change by ageing 6.6.1
Creep 6.6.2
Property change by fatigue 6.6.3
Force of reaction against Shear modulus at low-rate deformation 6.7
low-rate deformation
Table 10 — Standard test piece (square)
Item Rubber isolator Lead rubber isolator
No. 1 No. 2 No. 3 No. 1 No. 2 No. 3
Inner steel plate side length,
ab× 100 × 100 240 × 240 400 × 400 100 × 100 240 × 240 400 × 400
mm
Number of lead plugs — — — — 4 4 4
Diameter of lead plug, mm — — — — 14,5 34,5 57,5
Thickness of a single inner
t
1 to 2 2 to 3 3 to 4 1 to 2 2 to 3 3 to 4
s
steel plate, mm
Thickness of a single rubber
t 2 5 9 2 5 9
r
layer, mm
n
Number of rubber layers 6 6 6 6 6 6
Thickness of outside cover
t
5 5 10 5 5 10
o
rubber, mm
16 © ISO 2005 – All rights reserved

Table 11 — Standard test piece (circle)
Item Rubber isolator Lead rubber isolator
Inner steel plate outer
d
150 250 500 150 250 500
o
diameter, mm
Inner steel plate inner
diameter, mm
d
7,5 12,5 25 30 50 100
i
(diameter of lead plug)
Thickness of a single inner
t
1 to 2 2 to 3 3 to 4 1 to 2 2 to 3 3 to 4
s
steel plate, mm
Thickness of a single rubber
t 1,5 2,0 4,0 1,5 1,8 3,5
r
layer, mm
n
Number of rubber layers 20 25 25 20 28 28
Thickness of outside cover
t 4 6 8 4 6 8
o
rubber, mm
Key
1 compression force load cell
2 frame
3 bearing
4 actuator
5 test piece
6 upper and lower loading platens
Figure 4 — Example of compression testing machine

Key
P compressive force
1 displacement gauge
2 test piece
a
The distance from the core of the laminated body to each displacement gauge shall be constant.
Figure 5 — Compression displacement measurement sensor
6.2.1.3 Test piece
The test piece shall be as specified in ISO 22762-2 or ISO 22762-3.
6.2.1.4 Test conditions
6.2.1.4.1 Test temperature
The temperature of the laboratory should preferably be in accordance with ISO 23529. When the test is
conducted at another temperature, the test temperature shall be recorded.
6.2.1.4.2 Conditioning time for a test piece
Test pieces < 250 mm thick shall be left for at least 24 h after vulcanization. Thicker isolators shall be left for
at least 48 h.
Before a test, the test piece shall be left for 6 h to 24 h or more in the environment where the test machine is
located, and the temperature of the surface of the test piece shall be recorded. The conditioning time shall be
chosen so that the temperature of the test piece is the same as the environment.
6.2.1.4.3 Compressive force used in test
The maximum compressive force shall be specified by the structural engineer. If a standard test piece is
employed, it shall be loaded with the compressive force that is equivalent to the design compressive stress
σ as defined in ISO 22762-2 or ISO 22762-3.
The relation between compressive force and compressive stress is as follows:
PA=⋅σ
load
The tolerance shall be within ± 5 % of each compressive stress.
18 © ISO 2005 – All rights reserved

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