elastomer for heavy engineering applications

8/11/2019 Elastomer for Heavy Engineering Applications

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Elastomer for Heavy

Engineering Applications


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(a)Laminated Bearing

Sandwich structure

between elastomer

and steel plate

Widely used becauseit is able to prevent &

reduce the movement

of the bridge due to

few factors(earthquake, creep,

etc)


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The number of steel plate, will increase the

amount of load that can be sustain by the bridge


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(b) Plain Pad Bearing

Consist of rubber,

without the steel plate


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( c ) Strip bearing

Strip bearing similar with plain pad

bearing but the length of the bearing islonger than its width.


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( d ) Pot Bearing

Pot bearing bearing which consists

of solid rubber block and it is located in

between metal piston and metal

cylinder.


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Pot Bearing


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Plain Pad Bearing

Laminated Bearing


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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.
http://www.earthquakeprotection.com/benicia_martinez_bridge.htmlhttp://www.earthquakeprotection.com/benicia_martinez_bridge.htmlhttp://www.earthquakeprotection.com/benicia_martinez_bridge.htmlhttp://www.earthquakeprotection.com/benicia_martinez_bridge.htmlhttp://www.earthquakeprotection.com/benicia_martinez_bridge.htmlhttp://www.earthquakeprotection.com/benicia_martinez_bridge.htmlhttp://www.earthquakeprotection.com/benicia_martinez_bridge.html


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Main materials used as bridge bearing:

ELASTOMER


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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)


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Types of Elastomer used as bridge

bearings

Natural Rubber

HDRB ( High Damping Rubber )

Neoprene SBR

EPDM

NBR


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Why Elastomer?

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


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Disadvantages

Expensive (especially for rubber with highresistance to ageing)

Can be attack by:

ester

ketone

hydrocarbon with nitrogen

aromatic


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Physical PropertiesNatural

RubberSBR EPDM Neoprene Nitrile Urethane Silicone Fluorocarbon

Specific Gravity 0.93 0.94 0.86 1.23 1.001.05 to

1.250.95 to 1.20

1.4 to

1.95

Durometer, Range 30-100 40-100 30-90 40-95 30-90 55-100 25-90 55-90

Tensile Strength E F-G VG VG VG E F-G VG

Elongation 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

Weathering

Resistance P-F F E VG F-G G-E E E

Low Temperature

Limit*

-10TO -

50F

0TO -

50F

-20TO -

60F

-10TO -

50F

-30TO -

40F

-10TO -

50F

-65TO -

150F+10TO -40F

High Temperature

Limit*

158TO

225F

158TO

225F

300TO

350F225F 275F 250F

400TO

550F400TO 450F

Comparison of physical properties of polymer

P = Poor F = Fair G = GoodVG = Very

Good E = Excellent


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Neoprene = polychloroprene

First Choice


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Polychloroprene before vulcanization


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Polychloroprene after vulcanization


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Natsyn 2200 100.0Zink oxide 3.0stearic acid 2.0

Wingstay 100AZ 1.0VANOS 3C 2.0VANWAX H 2.0HAF (N-330) carbon black 50.0

aromatic oil 10.0Sulphur 0.5MOFAX 1.9

TOTAL 172.4

NEOPRENE PADS:

FORMULATION


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NEOPRENE PADS:

FORMULATION

Properties, cured 17 minutes @ 143C

Hardness, shore A 62

Tensile, MPa(psi) 26(3750)

Elongation,% 650Density, Mg/m3 1.10

Tear strength, Die C, kN/m (pli) 68(390)

Compression set after 22 Hours@70C (158F)

Method B, % Set 13


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Methodology inpreparing the

laminated bearing


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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)


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elastomer for heavy engineering applications

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