Twin Rotor Damper (2010)
Videos of active flutter-control experiments in our wind tunnel. The critical wind speed of a bridge deck section model is considerably increased by means of an active mass damper. The control moment is generated by two unbalanced masses rotating at a constant speed. Since the eccentric masses are connected by a tooth belt, they are steadily in equilibrium and thus only very low motor power is needed. The ratio of the active mass to the mass of the model is 1%. Experiments with a mass ratio of 0.5% have also been successfully completed.
Publication
Scheller, J.; Starossek, U. (2008). "A new energy-efficient device for active control of bridge vibrations." Report, IABSE Congress "Creating and Renewing Urban Structures Tall Buildings, Bridges and Infrastructure," Chicago, USA, September 17-19, 2008.
Starossek, U.; Scheller, J. (2008)."A novel active mass damper for vibration control of bridges." Proceedings, 4th International Conference on Bridge Maintenance, Safety, and Management (IABMAS08), Seoul, Korea, July 13-17, 2008.
HD videos (1920 x 1080) |
Alternative video formats (704 x 396) |
Description
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The video presents our wind tunnel and shows important elements of the tested bridge deck section model. |
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The control device is deactivated. At a constant wind speed of 9.0 m/s, |
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The control device is deactivated. At a constant wind speed of 10.0 m/s, the model is dynamically indifferent (critical wind speed).
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The control device is deactivated. At a constant wind speed of 11.0 m/s, the model is dynamically instable (overcritical wind speed).
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The control device is deactivated. The wind speed is rapidly increased from 0 m/s. At an overcritical wind speed of 20.2 m/s, the model exhibits torsional divergence (statically instable model). This is the maximum wind speed at which the model can be stabilized by any control device.
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The control device is activated (control mode with continuously rotating masses). The model is excited and the control automatically initiates. Then, the wind speed is rapidly increased from 0 m/s up to 19.2 m/s and, subsequently, it is slowly further increased until torsional divergence appears. The model remains dynamically stable at all wind velocities.
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The control device is activated (control switches automatically on and off). At a wind speed of 15.0 m/s, the model is excited and the control automatically initiates. After few seconds, the wind speed is increased until torsional divergence appears. The model remains dynamically stable at all wind velocities.
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The control device is deactivated. The wind speed is rapidly increased from 0 m/s up to 15.0 m/s and remains constant. After a while, the model begins self-excitedly to vibrate with increasing vibration amplitudes. The model is dynamically instable.
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The control device is activated. The wind speed is rapidly increased from 0 m/s up to 15.0 m/s and remains constant. After a while the model begins self-excitedly to vibrate. The control device limits the amplitudes of the vibration. The model is dynamically stable.
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Slow-motion video of initiated control.
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