Vibration analysis and design optimization of sandwich cylindrical panels fully and partially treated with electrorheological fluid materials

Compared with viscoelastic materials, electrorheological fluids can be effectively used to suppress the vibration over a broad frequency and temperature range. In this study, vibration analysis and damping characteristics of sandwich cylindrical panel structures using semiactive electrorheological fluid treatments have been investigated for different boundary conditions. Unconstrained viscoelastic material has been used at boundary and untreated locations to seal electrorheological fluids. First, an efficient finite element method has been formulated to investigate the effect of electric field intensity and thickness of top constrained elastic layer on the vibration and damping performance of the viscoelastic- and electrorheological-based sandwich cylindrical panel. Then, a design optimization methodology has been developed to simultaneously optimize the number of unconstrained viscoelastic and constrained electrorheological fluid patches and their distributions, thickness ratios of the electrorheological core and constrained elastic layers to base layers, and the external electric field intensity. The methodology integrates the finite element model of the sandwich panel with the combined genetic algorithm and sequential quadratic programming to effectively identify the global optimal solutions. The results show that for some boundary conditions, the sandwich panel partially treated with electrorheological fluids provides better damping performance compared with that of fully treated.