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Facility
Centrifuge
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A view of the arm and bucket of the centrifuge. This centrifuge, in terms of radius (9.1 m to bucket floor), maximum payload mass (4500 kg), and available bucket area (4.0 m2) is one of the largest geotechnical centrifuges in the world. The centrifuge is capable of producing 75g's of centrifugal acceleration at its effective radius of 8.5m. The centrifuge capacity in terms of the maximum acceleration multiplied by the maximum payload is 53 g x 4500 kg = 240 g - tonnes. |
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A view of the centrifuge axis, with the drive motor in the foreground. The long-cylinder on the side of the arm is one of two nitrogen gas bottles that pressurize the hydraulic system for the shaker. The gray enclosures at the top of the photo contain the on-board computers and select other components. These items are kept close to the centrifuge axis to minimize the g-field they are subjected to. |
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This is the servo-hydraulic shaking table upon which the model containers are mounted. For a rigid shaking mass of 2700 kg (model plus container) and a hydraulic pressure of 24 MPa, the actuators have the capacity to produce between 14 and 30 g shaking accelerations at frequencies up to 200 Hz. The maximum absolute shaking velocity is about 1 m/s and the stroke is 2.5 cm peak to peak. Two pairs of single acting actuators, one on each side of the container, provide a net peak actuator force of 400 kN. |
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A view of a flexible-shear-beam model container mounted on top of the shaker. The shaker actuators are controlled by a conventional closed-loop feedback control system. A simple correction scheme is used to precondition the command signal to improve the coherence and frequency content of the shaking table motions. The shaker provides reproduceable and scalable base time histories that have included step waves, sine waves and sine sweeps, and simulations of ground motions recorded during past earthquakes. |
Horizontal Shaking Table
Please see Training Documents under Other Training link on our EOT page for an introductory overview of the shakers.
Biaxial Shaking Table
Please see Training Documents under Other Training link on our EOT page for an introductory overview of the shakers.
Robot
A gantry robot with changeable manipulator tools and an on-board tool rack can be used to perform multiple tasks without stopping the centrifuge. Onboard robotics, for example, allow more accurate simulation of construction processes, which can, for example, control effectiveness of soil improvement and influence behavior of geotechnical systems such as pile groups. Users can use the gripper tool to drive piles sequentially, apply load cycles to structures, and manipulate objects to simulate construction processes. The robot can be used to perform in-flight in-situ site characterization tests using geophysical testing methods. These tests can help relate data in the centrifuge models to field conditions and can be used to study the evolution of material properties through a series of shaking events.
Model Containers
Data Acquisition Infrastructure
The Data Acquisition Infrastructure allows researchers to record information from their experiment during all stages of model construction and testing. The infrastructure consists of several parallel systems that can be operated in combination or independently. Each system is described in detail as a component of the Data Acquisition Infrastructure Equipment item within the Site Specifications Database. Users should refer to the component descriptions to learn more about the available data acquisition infrastructure.
The Center for Geotechnical Modeling also maintains an online archive for detailed specifications. The archive follows a basic directory structure. Users can browse for information by browsing the folder structure.
The data acquisition infrastructure binder is located at:
http://cgmfileserver.ucdavis.edu/binders/Data Acquisition Infrastructure.
Sensor List
Click here for a list of sensors available to our researchers.
LAN Infrastructure
Telepresence
Telepresense allows off-site researchers and P.I.s to experience, in real time, experiments.