Finite Element Simulation For Active Vibration Control Of Photostrictive Laminated Structure

The application of smart materials in the vibration control of structures is one of the hotspots of engineering research in recent years.The traditional actuators made of piezoelectric,ferroelectric,and magnetoelectric smart materials require complex accessorial devices for activating electric or magnetic signals,so the actuators are limited in size.They also require connecting hard-wire to made up the circuit loop,so there is electromagnetic noise to interfere the control signal transmission.The new smart material,lanthanum modified lead zirconate titanate(PLZT),can directly generate stress and strain under strong light irradiation with the photostrictive effect,which can avoid the electromagnetic limitation.It has become the focus of research using the photostrictive actuator to realize the vibration control.The operating principle of photostrictive actuator is introduced in detail.Based on this,a multi-field coupling finite element formulation of beam and plate structure laminated with the photostrictive actuators is developed.The model considers the effect of photostrictive actuators on the inertial mass and effective stiffness of the structures,and it can be applied to complex boundary conditions.The optimal fuzzy control algorithm is used to realize multi-modal vibration control.This algorithm is proposed on the basis of the combination of linear quadratic(LQ)optimal control and fuzzy one.This method can resolve the contradiction between the linear system control method and nonlinear actuating characteristics of photostrictive actuators.The optimal controller takes the light-induced strain as the input,converting the dynamics equation into a linear system,and obtains the time-varying optimal control law,that is,the required photo-induced strain.The fuzzy controller establishes the fuzzy relationship to represent the nonlinear relationship between the strain of the actuator and the illumination intensity,and adjust the light intensity to makes the true actuator strain to approach the optimal control law.The design of fuzzy control is independent of optimal control,and the parameters of the controller can be optimized using genetic algorithms.The finite element simulation results show the correctness of the finite element formulation and the effectiveness of the multi-modal vibration control method.