It is quite important for aircraft wing design to improve the aeroelastic characteristics, which are based on an interaction between aerodynamic and structural characteristics. Until now, mass balancing that adjusts the position of the center of gravity of the wing and aeroelastic tailoring that adjusts the position of the elastic axis of composite material were proposed and they have been successful to increase the flutter and divergence dynamic pressures. However, the aeroelastic characteristics of the wing structure designed by using mass balancing or aeroelastic tailoring are invariant through the flight envelope. It means that these are passive control method. On the other side, as for active control method, the application of control surfaces or piezoelectric materials to aeroelastic control is attracted attention recently, and is called aeroservoelasticity. It has been expected that more flexible design and operation, for example adaptively changing the wing shape according the flight state, can be possible.
Flutter, one of aeroelastic phenomena, is unstable self-exciting vibration. It is very dangerous matter, because it causes total failure of structures in a matter of seconds. Hence, flutter suppression is one of the most important subjects in the field of aeroservoelasticity and there have been many researches since a few decades before. Control surfaces of smart materials such as piezoelectric materials, shape memory alloy and so on are applied. Especially, piezoelectric actuators excel control surface in simple equipment and wide bandwidth, and farther application of piezoelectric materials to aeroservoelasticity has been expected. PZT has outstanding feature as actuator in terms of well amplitude of induced strain, and wide bandwidth, quick response, and PVDF has as sensor because of wide bandwidth, lightweight, flexibility and shock resistance. PVDF and PZT have been expected as composition elements of sensor/actuator that are embedded in structures.
In this work, active flutter suppression method of composite plate wings using PZT actuator and modal sensor which consists of PVDF sensor is proposed. Especially, the importance of first twisting mode in flutter suppression is clarified through the numerical examples.
edited by Takehiro HORA