Vibration responses and suppression of variable stiffness laminates with optimally steered fibers and magnetostrictive layers

This paper examines the vibration of fiber-steered laminated plates, such as those used in the skins of a sandwich panel, manufactured by automated fiber placement. We use third-order shear deformation theory, hybrid Fourier-Galerkin method, and numerical integration technique to predict their vibration responses, and to study the role of manufacturing defects, in particular gaps and overlpas, as well as the parameters representing the stiffness of the sandwich core. With the aim of improving both structural and vibration performance, we first adopt a passive approach to search for optimal fiber paths that can concurrently maximize the undamped dynamic out-of-plane and in-plane stiffness of laminates with gaps and overlaps. To further reduce vibration, we then follow an active approach that uses magnetostrictive layers to suppress the structural vibration of laminates with optimal vibration characteristics. The results of the vibration analysis show that for plates with gaps, as opposed to those with overlaps, the dynamic out-of-plane deflection has a higher amplitude and a lower frequency than that of a defect free plate. In addition, the results show that magnetostrictive layers with a higher gain control can lead to a lower vibration frequency, and better attenuate the vibration response of the panel. (C) 2016 Elsevier Ltd. All rights reserved.