Improved Higher Order Free Vibration Analysis of the Curved Sandwich Panels with Magneto-Rheological Fluid Core

In this study, according to capability of magneto-rheological fluids to change the stiffness and damping of structure, they can be used in the core of sandwich panel. The studied sandwich panel is double curved with simply support boundary condition. In order to derive the governing equations of motion, an improved high order sandwich panel theory and Hamilton's principle are used for the first time. Then the effect of magnetic field on the frequency of the panel has been investigated. The effects of changing the geometric parameters such as aspect ratio, thickness of MR layer, radius of curvature and thickness ratio on the characteristics of vibration panel have been studied. The obtained results showed that the natural frequencies of panel increase by increasing magnetic field strength to Bs (saturation magnetic field). Also it increases by increasing the panel aspect ratio, and reduces by increasing the core thickness to panel thickness ratio. Likewise the obtained results showed that natural frequencies for the case of double curved panel are more than single curved and flat panels. Therefore, by changing these parameters, the natural frequency of the system, can be changed in the desired range, and also by having a controllable magnetic field in the system, the natural frequency of the system can be controlled.