CASE STUDIES
CASE I: Wave Simulator
 Huber, Inc., New Orleans, LA, provided, installed and operated hydraulics and controls for a land-based simulation of sea conditions on LNG Tanker moored offshore. LNG operations include the process of converting liquefied natural gas at -250 degrees F to an ambient natural gas for transfer to shore facilities; required successful testing under simulated conditions replicating sea state 5, wave heights of 4 meters (13.1 feet).
To replicate sea state conditions, the table is pitched and rolled around a single swivel point. The motion table is 110 feet long, 14 feet wide and 29 feet off of the ground when level. It weighs approximately 500,000 lbs.
To simulate the sea state, a sinusoidal motion profile cycling +/- 6.2 degrees every 13.7 degrees for pitch. Roll cycles simultaneously at +/- 6.3 degrees every 12.1 seconds. Six degrees may not sound like a lot. But this huge platform is also pitching up and down 24 feet at speed of up to 47 inches per second while the roll is cycling.
To provide the pitch and roll motions, a hydraulic/electronic control system was devised consisting of a 6,000 gallon/1700 horsepower hydraulic power unit, two 720 gallon accumulator stands, several large manifold blocks, Hydraulyne cylinders and pipe swivel assemblies, and a complete electronic control system from operator interface to closed loop position control.
"The system performed flawlessly." says Dennis Garrard, Huber, Inc., Project Manager. "The unusual wrinkle is that the was used once, then dissaembled and put into storage. So you can say this motion project moved to a successful and fast conclusion. |
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