Active Vibration Control Of The Composite Cantilever Beam

In the context of the rapid development of China’s industry,aerospace,automobile and other industries,the equipment is increasingly lightweight,and lightweight equipment is often at the expense of structural rigidity,resulting in equipment under external disturbance is easy to produce vibration and cause resonance between structures.In recent years,the rapid development of intelligent materials has brought more possibilities for the control of structural vibration,and this paper takes the active constraint layer damping cantilever beam and the intelligent constraint layer damping cantilever structure as the research object for the following work:The active constrained layer damping cantilever is composed of a base beam,a viscoelastic layer and a piezoelectric constraint layer,when the structure vibrates under the external disturbance,the sensor picks up the structural vibration signal and transmits it to the controller,and the controller calculates the corresponding control voltage to the piezoelectric constraint layer to make the piezoelectric constraint layer produce the desired deformation,aggravate the shear deformation of the viscoelastic material and suppress the vibration of the structure by dissipating energy.In this part,the dynamic equation of the cantilever structure of the active constrained layer is derived based on the finite element method and the GHM model.Then,the corresponding iteration matrix and modal space are constructed in the physical space and state space to simplify the system dynamics model.The particle swarm optimization algorithm is used to optimize the parameters of the system controller.The influence of controller parameters,the laying position of piezoelectric sheet and viscoelastic layer,and different excitation signals on the control effect and control cost of structural vibration were comparatively studied.The results show that the simplified method of physical space model can retain the low-frequency characteristics of the original system with high precision,and the physical significance is clear.The modal space model simplification method can realize the decoupling of non-proportional damping and truncate the low-order mode of the retention system.The controller parameters optimized by particle swarm optimization can effectively balance the control effect and control cost.Under the same control parameters,the closer the piezoelectric layer and viscoelastic layer are laid to the free end,the weaker the control effect of the system.The controller can effectively track the response of the low-order mode of the damping cantilever structure of the active constraint layer under different excitation signals.The intelligent constraint layer damping cantilever beam is composed of a base beam,a viscoelastic layer,a piezoelectric constraint layer and a piezoelectric sensing layer,when the structure vibrates under external disturbance,the piezoelectric sensing layer replaces the sensor to pick up the vibration signal and complete the active control of structural vibration.In this part,based on the modeling method of intelligent constraint layer damping cantilever structure,the simplification method of physical space and modal space model,the static damping characteristics of intelligent constraint layer damping cantilever beam and the active control of structural vibration are preliminarily studied.The thicker the viscoelastic layer of the intelligent constraint layer damping cantilever structure,the weaker the damping effect of the structure;The thicker the piezoelectric confinement layer,the stronger the damping effect of the system;The controller can effectively track the response of the low-order mode of the intelligent constrained layer damping cantilever structure under different excitation signals.