Transcript Elastomer for Heavy Engineering Applications

Elastomer for Heavy
Engineering Applications
(a)Laminated Bearing
• Sandwich structure
between elastomer
and steel plate
• Widely used because
it is able to prevent &
reduce the movement
of the bridge due to
few factors
(earthquake, creep,
etc)
• The number of steel plate, will increase the
amount of load that can be sustain by the bridge
(b) Plain Pad Bearing
• Consist of rubber,
without the steel plate
( c ) Strip bearing
“Strip bearing” similar with “plain pad
bearing” but the length of the bearing is
longer than its width.
( d ) Pot Bearing
“Pot bearing” – bearing which consists
of solid rubber block and it is located in
between metal piston and metal
cylinder.
Pot Bearing
Plain Pad Bearing
Laminated Bearing
Example the needs of good bridge
bearings
Benicia-Martinez Bridge
The bearing for this bridge
Increased to 53 inch
whenever sustained
5 mil. Lbs loads.
Main materials used as bridge bearing:
ELASTOMER
Function of Elastomer
• absorb the vibration
• allow the changes in the length of bridge
• ease of installation
• used to cover the metal plate
(for laminated bearing)
Types of Elastomer used as bridge
bearings
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Natural Rubber
HDRB ( High Damping Rubber )
Neoprene
SBR
EPDM
NBR
Why Elastomer?
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Long lasting
Good in impact absorption
Good bonding with metal
Good resistance to ageing
Good tearing properties
Good physical properties
sesuai untuk panas dan sejuk
Good resistance to oil and chemicals
Disadvantages
• Expensive (especially for rubber with high
resistance to ageing)
• Can be attack by:
 ester
 ketone
 hydrocarbon with nitrogen
 aromatic
Comparison of physical properties of polymer
Physical Properties
Natural
Rubber
SBR
EPDM
Neoprene
Nitrile
Urethane
Silicone
Fluorocarbon
1.4 to
1.95
0.93
0.94
0.86
1.23
1.00
1.05 to
1.25
0.95 to 1.20
30-100
40-100
30-90
40-95
30-90
55-100
25-90
55-90
E
F-G
VG
VG
VG
E
F-G
VG
VG-E
G
G
G
G
G-VG
VG-E
F-G
Compression Set
G
G
G
F-G
G
G-E
G-E
G-E
Heat Resistance
F
F-G
VG-E
F-G
G
F-G
E
E
Resilience or Rebound
E
F-G
G
VG
F-G
F-E
G
F
Impact Resistance
E
E
G
G
F
G-E
P-G
E
Abrasion Resistance
E
G-E
G-E
G-E
G-E
E
P-F
F-G
Tear Resistance
E
F
F-G
F-G
F-G
E
P-F
F
Cut Growth
E
G
G
G
G
G-E
P-F
P-F
Flame Resistance
P
P
P
G
P
P-F
F-G
VG-E
Impermeability, Gas
F
F
F-G
F-G
G
P-F
F-G
E
P-F
F
E
VG
F-G
G-E
E
E
Low Temperature
Limit*
-10° TO 50°F
0° TO 50°F
-20° TO 60°F
-10° TO 50°F
-30° TO 40°F
-10° TO 50°F
-65° TO 150°F
+10° TO -40°F
High Temperature
Limit*
158° TO
225°F
158° TO
225°F
300° TO
350°F
225°F
275°F
250°F
400° TO
550°F
400° TO 450°F
Specific Gravity
Durometer, Range
Tensile Strength
Elongation
Weathering
Resistance
P = Poor
F = Fair
G = Good
VG = Very
Good
E = Excellent
First Choice
Neoprene = polychloroprene
Polychloroprene before vulcanization
Polychloroprene after vulcanization
NEOPRENE PADS:
FORMULATION
Natsyn 2200
Zink oxide
stearic acid
Wingstay 100 – AZ
VANOS 3C
VANWAX H
HAF (N-330) carbon black
aromatic oil
Sulphur
MOFAX
TOTAL
100.0
3.0
2.0
1.0
2.0
2.0
50.0
10.0
0.5
1.9
172.4
NEOPRENE PADS:
FORMULATION
Properties, cured 17 minutes @ 143C
Hardness, shore A
Tensile, MPa(psi)
Elongation,%
Density, Mg/m3
Tear strength, Die C, kN/m (pli)
62
26(3750)
650
1.10
68(390)
Compression set after 22 Hours@70C (158F)
Method B, % Set
13
Methodology in
preparing the
laminated bearing
Preparation of rubber compound- according to
the right composition
Prepare the metal plate
Apply the bonding agent to the metal plate
Prepare the rubber compound and metal
plate
Compression Moulding
Testing ( to test the quality and the properties)