Vibration analysis and design optimization of sandwich beams with constrained viscoelastic core layer

Dynamic properties of sandwich beam-type structure are analyzed using finite element method based on a nonlinear model for displacement field in the viscoelastic core layer of the beam structure. Results obtained for the nonlinear and linear models are compared to the test data available in literature. It is revealed that the nonlinear model provides more accurate results than the linear one. Parametric studies are carried out on the nonlinear model to illustrate the effect of viscoelastic core thickness on the loss factor and natural frequencies of structure. These results are also compared with those obtained for the linear model. Parametric studies on the nonlinear model revealing the sensitivity of the location of untreated and treated patch and the length of treated patch are presented. Finally, an optimization problem is formulated for the nonlinear model to locate the optimal distribution and numbers of partial treatments in order to attain the maximum damping in the sandwich beam for various boundary conditions.