A Controllable Flexible Micropump and a Semi-Active Vibration Absorber Using Magnetorheological Elastomers
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Authors
Behrooz, Majid
Issue Date
2015
Type
Dissertation
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Keywords
Fluid Transport System , Micropump , Semi-Active Control , Soft Magnetorheological Elastomer , Variable Stiffness and Damping , Vibration Absorber
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Abstract
This study is focused on magneto-fluid-solid interaction analysis of a soft magnetorheological elastomer (MRE) controllable flexible micropump. In addition, material characterizations of MRE, modeling, fabrication and testing of a MRE-based vibration absorber system are investigated.Theoretical modeling and analysis of a controllable flexible magnetically-actuated fluid transport system (CFMFTS) is presented. For the first time, soft magnetorheological elastomer (MRE) is proposed as an actuation element in a fluid transport system (micropump). The flexible micropump can propel fluid under a fluctuating magnetic field. Magnetic-fluid-solid interaction analysis is performed to determine deflection in the solid domain and velocity of the fluid under a magnetic field. The effects of key material and geometric system parameters are examined on the micropump performance. Two- and three-dimensional analyses are performed to model the asymmetric deflection of the channel under a magnetic field. It is successfully demonstrated that the proposed system can propel the fluid in one direction.In addition, a novel semi-active variable stiffness and damping absorber (VSDA) is modeled, built and tested. Magnetically induced mechanical properties of MRE and their controllability are investigated by quasi-static and dynamic experiments. The VSDA is modeled, using springs, dashpots and the Bouc-Wen hysteresis element, fabricated and implemented in a scaled building to assess performance. Experiments are performed on a single VSDA, integrated system of four VSDAs, and a scaled building supported by four VSDAs. To demonstrate feasibility, a scaled, two-story building is constructed and installed on a shake table supported by four prototype VSDAs. The properties of VSDAs are regulated in real time by varying the applied magnetic field through the controller. A scaled earthquake excitation is applied to the system, and the vibration mode is controlled by a Lyapunov-based control strategy. The control system is used to control displacement and acceleration of the floors. Results demonstrate that the proposed VSDA significantly reduces acceleration and relative displacement of the structure.
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In Copyright(All Rights Reserved)