Optimization of the Flutter Load by Material Orientation

Abstract

The present work concerns optimization of the stability of composite plates for supersonic flutter. A Finite element model of the structure is applied. The individual material orientation within each finite element defines the degrees of freedom in the design space. Design iterations are based on analytical sensitivity analyses, derived by Pedersen and Seyranian. Plaut's flutter instability condition is discussed. The condition implies the possibility of an accurate flutter analysis without reducing the eigenvalue problem. For one particular choice of material, an optimal design, in the case of a rectangular, simply supported plate, is found. Design iterations on a delta-shaped plate supported as a cantilever are discussed. A condition for when static divergence is not a possible consequence of the aerodynamic load for any design is derived.