Axially functionally graded beams and panels in supersonic airflow and their excellent capability for passive flutter suppression

Abstract

Mode localization in the airflow direction can be observed in aeroelastic structures. On the contrary, can the aeroelastic stability of the structure be enhanced if the geometric sizes and material properties vary along the airflow direction? The present study mainly solves this problem. The mode localization phenomenon in panel flutter in supersonic airflow is displayed. Three arbitrary thickness functions according to the flutter mode are taken into account. Their panel flutter behaviors show that although the consistency between the variation of thickness and flutter mode can increase the flutter bound slightly, the increments are limited. Consequently, a novel strategy for passive control of the panel flutter is proposed by the optimal axially functionally graded (AFG) design of the panel. By investigating the sensitivity of each element in the aerodynamic stiffness matrix to the aeroelastic stability of the structure, the optimal thickness and Young's modulus functions are given out. Simulation results show that the optimal AFG design in this study can suppress the flutter essentially. It can increase the flutter bound of the structure by changing the flutter modes rather than only makes a slight extension on the original basis. Moreover, the designed thickness and Young's modulus are reasonable and applicable.