<p>In this study, the vibration of a sandwich cylindrical shell is investigated and controlled using the particle swarm optimization (PSO) method. Initially, Hamilton's principle and the semi-analytical Galerkin method are employed to derive the dynamics of the sandwich cylindrical shell, which consists of three layers. The internal (base) layer is a 10-layered composite cylindrical shell, the middle layer incorporates a smart material, electrorheological fluid (ERF), for control purposes, and the third layer is a constrained layer. The sandwich cylindrical shell is subjected to harmonic loading along its longitudinal axis, with the assumption that this load acts radially only. The system's frequency response is computed for scenarios where no voltage is applied to the ERF core, representing the uncontrolled frequency response of radial displacements. Subsequently, a novel control strategy is implemented. Unlike traditional approaches that apply constant voltages or rely on real-time feedback, this method uses PSO to calculate control voltages that minimize both vibration amplitude and energy consumption. By implementing the optimized voltages, the controlled frequency response and structural deformation of the sandwich cylindrical shell are computed across three different types of composite materials. The numerical results showcase the superior performance of the controlled response in mitigating system resonance compared to uncontrolled conditions.</p>