Open loop flutter control of optimally oriented smart variable stiffness plates under hygrothermal environment

Abstract

The present study investigates the impact of hygrothermal effects on the free vibration and flutter characteristics of a smart variable stiffness composite laminate (VSCL). This research seeks to underscore the inherent advantages of VSCLs in contrast to conventional straight fibre constant stiffness composite laminates (CSCLs). Utilizing curvilinear fibres, VSCLs offer a heightened level of customization, culminating in notably enhanced structural performance. The Genetic Algorithm is employed to obtain optimal fibre paths for the variable stiffness laminates. Introducing an active fibre composite layer as an actuator atop the optimally oriented VSCL laminate enhances its capabilities. A parametric inquiry into the influence of hygrothermal loading on the smart structure's free vibration and flutter traits is undertaken. While hygrothermal loading imparts vulnerability to the laminate, the introduction of voltage to the active fibre composite layer counteracts this weakening effect, effectively augmenting stiffness and concurrently enhancing the flutter parameters (velocity, frequency) intrinsic to the plate structure.