ANALYTICAL MODELING OF ELECTRORHEOLOGICAL MATERIAL BASED ADAPTIVE BEAMS

The use of electrorheological (ER) materials in adaptive structures ha s received much attention recently. ER adaptive structures are based o n controlling the pre-yield theology of the ER material, which is achi eved by applying different electrical fields to the ER material. In th is study the dynamic behavior of an ER material based adaptive beam wa s modeled. Previous modeling efforts were extended towards a more deta iled analysis of modal results. The adaptive beams focused on were com posed of three layers: an ER material controllable damping layer and s urrounding upper and lower elastic plates. A structural model of the a ssembly in a transverse continuous vibration mode subjected to simply supported boundary conditions was developed and analyzed. It was assum ed that each structure was subjected to sinusoidal actuation applied a t one or two locations. The model was tested under the conditions of v arying forcing frequency from 0-300 Hz, and applied electrical held fr om 0-3.5 kV/mm. Time domain displacement response, natural frequencies , and loss factors of the structures at varying electric fields and va rying damping layer thicknesses were obtained. The analytical results of the adaptive beam were compared with experimental results under the same physical conditions. Qualitative agreement between theory and ex perimentation resulted. In addition an effort was made to reduce the v ibration of the structure by selecting the optimum electrical held whi ch yields minimized vibration for each excitation frequency.