Vibration Control of Smart Flexible Structures Using ER Fluids

초록

This paper provides vibration control of smart flexible structures filled with an electrorheological(ER) fluid. Firstly, a field-dependent complex shear modulus of the employed ER fluid itself is distilled through an oscillatory test. A dynamic model of the smart structures is then developed by incorporating the measured modulus with conventional sandwich struture theory and finite element method(FEM). Moreover, two smart structures of a cantilevered beam and a rectangular plate are constructed by inserting the ER fluid. As for the smart beam, a control scheme to actively suppress tip deflection under variable excitation is formulated on the basis of the predicted field-dependent transfer function from the proposed model. The effectiveness of the control logic is empirically demonstrated in both the frequency and time domains. As for the smart plate structure partitioned into four ER fluid-field section, an extensive modal test is empirically conducted to identify natural frequencies and mode shapes with respect to both the magnitude and the area of the applied electric fields to the ER fluid domains. In order to evaluate the propoed methodology, globally and locally controlled mode shpes and natural frequencies from the experimental implementation are compared with ones predicted from the dynamic model with FEM. The results exhibit that the proposed smart structures with ER fluid have a great authority in tuning structural behaviors and elastodynamic properties.