400 g-ton Centrifuge
The 400 g-ton centrifuge, designed by Wyle Laboratories and fabricated by Alabama Dynamics, began operation in 1988. It has an asymmetrical rotor arm with a swinging payload platform on one end and a fixed counterweight compartment on the other. The operating radius, with the swing platform extended, is 18 feet. A payload volume and mass of 4x4x3 ft and 4000 lb respectively can be accommodated by the centrifuge.
A 900 horse-power (684 kW) Direct Current (DC) drive system powers the centrifuge through a right-angle gearbox with a 6.4 to 1 gear reduction. The centrifuge is capable of accelerating a payload to a maximum of 200g in about 14 minutes. Four large pneumatically actuated disk brakes are used to stop the centrifuge in emergency situations. Other prominent features of the centrifuge include a cooling system along the centrifuge chamber wall, an active in flight balancing system, and a dedicated real-time control and monitoring system. To learn more about the 400 g-ton centrifuge, its geometry, and previous projects, please refer to this document. The operations and maintenance guides can be obtained from the links in this sentence, although these documents are currently being updated.
The centrifuge is currently equipped with a full complement of state-of-the-art data acquisition and experiment control systems, facilitating any possible geotechnical and non-geotechnical test. A high-speed, high channel count, modular data acquisition systemd he mounted on the centrifuge arm acquires data from any type of conventional analog transducer, including accelerometers, pressure transducers, LVDTs, and strain gauges. An inventory of instrumentation which is currently being updated is attached here. All acquired data is communicated to display terminals in the control room, or elsewhere, via a high-speed wireless network. A powerful servo-hydraulic shaketable is utilized to apply earthquake, and non-earthquake, motion to a test specimen in flight. Soil specimens can be used with the shaker in an array of shake table containers. The details of a laminar container developed at CU Boulder are presented here. A full array of equipment including video, digital still, and machine vision systems allow visual monitoring of the test specimen and provide additional data acquisition capabilities. A number of systems allow remote manipulation of a test specimen in flight. A three channel rotary union supplies hydraulic and pneumatic force to spinning centrifuge through a slipring assembly. Hydraulic and pneumatic pressure is used to drive linear actuators, pumps, and pressurize test specimens. The centrifuge is also a equipped with a four axis digital servo/stepper motor motion control system. The motion control system is used to push, pull, drag, rotate, and move a test specimen in any possible direction. One current application of the system is automating cone penetrometer and vane-shear measurements.
The geotechnical centrifuge facilities at the University of Colorado, Boulder are available for use by research institutions and by private industry. Please contact Prof. John McCartney (john.mccartney(at)colorado.edu) for information regarding the use of these facilities by outside parties and for specific questions regarding data acquisition and experiment control systems.