Flutter and buckling characteristics and active control of sandwich panels with triangular lattice core in supersonic airflow

Sandwich structures with lattice core are novel composite structures, but the aeroelastic behaviors of them have not been fully studied. This paper is devoted to investigate the flutter and buckling properties of sandwich panels with triangular lattice core in supersonic airflow, and the active flutter and buckling control are also carried out, which can provide theoretical basis for the use of sandwich structures in the design of aircrafts. The unsteady aerodynamic pressure is evaluated by the supersonic piston theory in which the yawed flow angle is taken into account. Hamilton's principle with the assumed mode method is applied to formulate the equation of motion of the structural system. The active controller is designed by the displacement feedback method. Aeroelastic characteristics of the sandwich panels are studied, and the influences of the aerodynamic pressure on the frequency and mode shape of the panel are analyzed. The effects of yawed flow angle on the flutter properties of the sandwich panel are also analyzed. When considering the external in-plane load, the buckling behaviors of the sandwich panel are investigated. Moreover, the flutter and buckling properties between the sandwich and equivalent isotropic panels are compared to show the superior aeroelastic properties of the sandwich panels. The effects of piezoelectric patch placements on the active flutter control are analyzed. The optimal locations of piezoelectric actuator and sensor pairs are obtained by the genetic algorithm. The present study verifies that the sandwich structures have different aeroelastic and flutter suppression properties, which is useful in the research of lightweight sandwich materials.