The seismic response of base-isolated structures with supplemental inertial devices subjected to stationary and real earthquake excitation is presented. Three types of devices, namely inertial mass damper (IMD), tuned mass damper-inerter (TMDI), and clutching inerter damper (CID), are considered. The seismic response of the base-isolated structure with and without inertial devices is compared to assess their effectiveness. Under stationary white-noise excitation, the optimum parameters of these devices were obtained. The criterion selected for optimality is the minimization of the mean-square relative displacement and absolute acceleration of the isolated structure. An equivalent linearization method was used for base-isolated structures with CID under stochastic excitation. It was observed that the IMD is not very effective in controlling the response of base-isolated structures. Optimally designed TMDI, on the other hand, was found to be effective in controlling the displacement and acceleration response of the isolated structure, with the effectiveness increasing as the inertance mass ratio increased. The CID involved in the base-isolated structure reduces the structural natural frequency and increases structural damping, thereby reducing isolator displacement and structural acceleration. The high-frequency components were present in the absolute acceleration of base-isolated structure with inertial devices (more pre-dominating for IMD and CID), which may have detrimental effects on installed high-frequency sensitive equipment.

In this research, free vibration analysis of epoxy-based laminated composite folded plate structures for thermal loads have been considered using finite element method. Eight noded isoparametric element with five degrees of freedom per node have been considered in the study. Folded plate formulation using 6 X 6 transformation matrix is applied to transform the element mass and stiffness matrices to global system matrices. Yang-Norris-Stavsky (YNS) theory along with rotary inertia have been used in the present formulation. Lamina material properties at elevated temperature have been used in the study. Parametric studies have been performed for laminated composite one-fold plate structure for various thicknesses, crank angle and fibre angle under different temperatures. Results reveal that rising thermal load reduces the stiffness of the structure considerably. As the presence of fold increases stiffness of the plate structures significantly, it can withstand increased temperature. Proper choice of fibre angle and thickness increases the stiffness of the structures thus making it more capable of resisting higher thermal load.

In this study, the SPL at the boundary and within the domain of a rectangular-shaped container with a flexible laminated composite panel with opening have been investigated. Finite Element Analysis (FEM) for the flexible panel has been done and coupled with the acoustic domain using the Boundary Element Method (BEM) through the mobility relation. A MATLAB program has been developed to find flexible panel behavior by FEM and BEM to calculate the sound pressure level for a cavity. Eight-noded isoparametric serendipity elements have been used to model the boundary. A pressure-velocity formulation has been adopted to model the acoustic domain with radiation impedance for window boundary. It has been shown that the presence of a thin flexible plate and opening, drastically changes the SPL pattern inside and at the boundary compared to a rigid cavity due to the relative movement of flexible panel and energy dissipation through the opening by radiation.