The method of successive decrease and the concept of harmonic wave filter in structural wave control

Abstract

Most of the available vibration control methods for flexible structures are based on the modal control method, which, however, sometimes meets with problems. For examples, the problem of spillover has not been solved adequately. And, for flexible large space structures with closely spaced natural frequencies, it is very difficult to use modal method to treat vibration control problems because the modes corresponding to closely spaced and repeated frequencies can not be computed accurately.

In recent years, the method of structural wave control has been developed, but it has not been studied sufficiently. The object of this paper is an attempt to solve some of the existing problems raised due to the application of the modal control method. A wave control method — the method of successive decrease is set up at first, which is aimed at one harmonic wave. Then, a new design method in wave control is proposed, based on the above method. The problem of control spillover is analyzed and the concept of harmonic wave filter is introduced.

As an example, the problem of the control of structures with closely spaced natural frequencies is treated by both the method of modal control and the method of successive decrease. The numerical results show that the method of successive decrease is more effective than the method of modal control. It proves that the method of successive decrease and the concept of harmonic wave filter is promising in solving the problems of structural control.