NSF Award
9903714
This Small Business Technology Transfer (STTR) Phase I project addresses the key requirement for the large diameter dish antennas, which is the ability to switch rapidly between positions of various satellites in the sky with minimum structural vibration. In order to minimize signal distortions due to vibrations various damping mechanisms are employed, which include material damping, friction damping, viscoelastic damping and viscous damping. A present method of reducing the vibration involves modifying the mass and stiffness of the structure by using polymer-based composites. Similarly in wind turbines, structural distortions due to aerodynamic effect in combination with the vibration related to the spinning of the blade reduce the efficiency of energy generation. Conventional hydraulic dampers and springs are not the best solutions for these applications. The proposer will use MR fluid based 'smart sensor' based actuator systems to reduce vibrations in structures similar to the ones mentioned above. Magneto-rheological (MR) fluids exhibit rapid change in viscosity (0 to 105) as a function of applied magnetic field. Their speed of response is of the order of millisecond, which make them the ideal fluids for 'smart actuators' or dampers. MR fluid based actuators are simple in construction and are compact. <br/> MR fluid based actuator will find wide application in damping vibrations in bridges, dish antennas, wind turbines, gas turbines. They can also replace shock absorbers in car and trucks to reduce vibration and tilting of the automobile during turning. Since the viscosity of these fluids can be controlled as a function of current they can also be used in variable resistance fitness or exercise machines.
