In this research, a smart structure with multielectrode configuration has been proposed, which contains electrorheological (ER) fluid. Multielectrode configuration gives the structure a capability to change its modal characteristics effectively. The proposed configuration also provides the effective vibration control performance with reduced power consumption in the smart structures. A finite element model has been developed for the analysis of a smart composite plate under fully and partially applied electric fields. The numerical results of the composite plate with ER fluid have been compared with the experimental results. The performance and energy consumption of the control system have been experimentally investigated for various applied areas of electric field by applying a semi-active control law to the vibrating composite plate.