A time-varying boundary method for multimodal vibration suppression of beam

As common components in huge underwater gliders, modal vibrations of flexible beams can affect the durability of structures and the precision of system. The current methods for suppressing the beam vibrations include the damping suppression, active control and absorbers, etc. The above control methods were gradually developed for the low frequencies and wide band. The accurate structures and excitation parameters should be obtained in the design processing. In this work, a time-varying boundary method is proposed based on the energy transfer phenomenon of time-varying boundary structure. The proposed method is effective for suppressing multi-order structure resonance simultaneously. A dynamic model of a time-varying boundary beam is established. The vibrations of time-varying boundary beam are obtained by a time-domain piecewise analytical method, which are compared with those from a finite element software. The vibrations of time-varying boundary beams and time-invariant beams are compared. The vibration suppression effect of time-varying boundary method is verified. The effects of the damping, time-varying range and time-varying speed on the vibration suppression characteristics are analyzed. The time-varying position optimization area is obtained. Note that the time-varying boundary method can simultaneously suppress the multimodal resonances of beam and reduce the resonance peaks with the highest energy.