An Analytical and Experimental Investigation of Electrorheological Material Based Adaptive Beam Structures

Modeling the dynamic behavior of the controllable structure itself is essential to the physical realization of electrorheological (ER) material based adaptive structures. Previous non-conclusive studies evaluated two well-known vibration theories, namely the Ross, Kerwin, and Ungar (RKU), and Mead and Markus models, in their relevance to ER based constrained layer structures. The present study consists of an in-depth theoretical and experimental investigation verifying the utility of these models in predicting the dynamic behavior of ER based structures. We restrict ourselves to a comparison between the structure's natural frequencies since the shear storage modulus dominates the material's rheological behavior. The material's loss modulus contribution to the structure's overall controllability is assumed to be negligible. The RKU and Mead and Markus theories adequately model the behavior of ER based adaptive beam structures. The model's accuracy depends upon uninhibited strain in the sandwiched layer, uniform thickness of the sandwich layer, and accurate determination of the material's rheological properties.