| In this dissertation, ER material based adaptive structures were investigated. The goal of the dissertation was to develop an understanding of the mechanical vibration behavior of selected ER smart structure configurations. ER smart structures were obtained by sandwiching ER material between two elastic face plates. Various beam-like and plate-like ER structural configurations were identified. The structural configurations selected ranged from simple to complex, depending on the geometry, number of controllable ER elements, and actuation and sensing locations of the ER adaptive structure. For each structural configuration, an analytical study was performed targeted at developing a model for parameters such as resonance frequencies, vibration levels, and loss factors. In conjunction with this theoretical effort, actual ER smart structures were fabricated and tested experimentally throughout the investigation. In both the experimental and analytical studies, variations in resonance frequencies, vibration levels, and loss factors of the structure were observed and/or predicted in response to changing applied electric field levels on the ER material layers. The observed tunable mechanical response of the ER adaptive structures was found useful for structural vibration control purposes. The research was performed as part of a multi-disciplinary team effort, funded by the U.S. Army Research Office, that included closely coupled neural network based real-time control and embedded optical fiber vibration sensing components. |
