Electrorheological Material Based Adaptive Beams Subjected to Various Boundary Conditions.

The semi-active vibration control capabilities of Electrorheological (ER) material based adaptive beams were investigated in this study. The adaptive nature of such ER beams was achieved by controlling the pre-yield rheology of the ER material in response to varying applied electric field levels. The cross-sectional configuration of the beams considered was based on sandwiching the ER material between elastic face plates. A dynamic model of the beam structure based on thin plate theory was developed. The resulting dynamic model was able to predict the structural vibration characteristics of the ER adaptive beam. The information determined included natural frequencies, loss factors, and transverse vibration responses at any location on the beam surface. These vibration characteristics were determined as functions of excitation frequency and applied electric field level. Also the beam model was developed for generalized boundary conditions. The boundary conditions considered in this study were: clamped-clamped, clamped-free, clamped-simply supported and simply supported. Variations in the natural frequencies, loss factors, and transverse vibration response of the adaptive structure were analyzed for the listed boundary conditions. Additionally, effects of variations of the damping layer thickness of the adaptive beam on the structural loss factor was studied. Results were compared for the boundary conditions studied, and considerable variations in beam vibration responses were observed. As a result, the semi-active control capabilities of ER material based adaptive beams were theoretically illustrated. [ABSTRACT FROM PUBLISHER]