Executive Summary : | Variable stiffness composites made of curvilinear fibers possess significant design advantages over conventional straight fiber composites. Unlike constant stiffness laminates, here the stiffness property can be varied spatially. Additionally, by optimising the tow angles of the variable stiffness laminates using Genetic algorithm can add further dimension to the capability of property tailoring. During the service life, the structure may get exposed to adverse hygrothermal conditions. Hence, the structural and aeroelastic response may be degraded due to weakening of its stiffness as residual stresses are generated within the laminate. In this context, an actuator layer made of active fiber composite patches can be used to regain the lost strength and enhanced response can be witnessed. The objective of the current work is devoted to study the hygrothermal effect on the natural vibration, flutter and gust response characteristics of smart optimally oriented variable stiffness composite laminates. To accomplish the objective, a MATLAB/Fortran based finite element code will be developed to perform free vibration analysis at different levels of temperature/moisture concentration level and preloaded actuator voltage. Subsequently, the recorded modal parameters will be exported to MSC. NASTRAN software using DMAP (Direct Matrix Abstraction Programming) module and flutter analysis will be performed. The p-k method of flutter solution will be employed to obtain the flutter characteristics at sea-level atmospheric conditions. |