Vibration Analysis And Active Control Of Truss Structure

Truss structure has a broad application in the aerospace industry. Specialenvironment of outer space makes it prone to get out of order, and affects aerospaceexploration and study adversely. The structure often goes wrong because ofuncontrolled large deflection or vibration amplitude. Therefore, appropriate researchmethod is necessary for analyzing structure’s vibration characteristics and activecontrol problems to achieve structure rational design and long-term safe operationtheoretically and realistically.Spectral element method is an exact frequency domain method to solvestructural dynamics. In this paper, spectral element method is used to get frequencydomain and time domain responses considering shear deformation under dynamicload, and results are more accurate and efficient compared with finite elementmethod. At the same time, piezoelectric materials and PID controller can controlstructure vibration in full-band actively and efficiently.First, we summarize basic principles, advantages and disadvantages of spectralelement method, obtain dynamic stiffness matrices and give an example to solve theproblem of dynamics of straight bar and Timoshenko beam. Researches show thatspectral element method could be used to get structure’s vibration characteristicswith better accuracy and higher computational efficiency including naturalfrequencies, frequency response functions and time course curves.Then, we integrate dynamic stiffness matrices of straight bar and Timoshenkobeam into truss structure’s, calculate its frequency domain and time domainresponses under dynamic load, and discuss influences of dynamic characteristics indifferent location of the structure with diverse structure conformations andparameters. It indicates that spectral element method is suitable for high frequencyvibration analysis especially.Finally, spectral element method is used to solve dynamics problem ofpiezoelectric laminated bar and obtain dynamic stiffness matrix of piezoelectrictruss. Classical speed feedback control algorithm is successful for active control ofthe vibration of truss structure. We analyse its dynamic characteristic betweenuncontrolled and controlled, influences of the number and the position ofpiezoelectric layer bar, and affects of the size of feedback control gain. Fact provesthat spectral element method ensures computed result’s efficiency and accuracy, andat the same time, has a positive effect for full-band vibration suppression ofdeployable truss structure.