Research On The Dynamic Characteristics Of Fluid-filled FGPM Cylindrical Shells

Pipeline systems are widely used in ships,which usually work accompanied by vibration that may lead to failure of the system stability and harmful noise that caused great influence to the concealment of the ship,so it has important engineering and military significance to realize the active control of vibration and noise of pipeline system.As the basic unit of actuators,FGPM materials are formed by incorporating the advantages of FGM materials and piezoelectric materials,which can effectively overcome the stress concentration and other problems easily caused by single-phase piezoelectric material,and greatly improve their reliability.The study of the dynamic characteristics of fluid-filled FGPM cylindrical shells can provides theoretical basis for the active control of vibration and noise of piping structures.In this paper,the dynamic characteristics of the fluid-filled functionally graded piezoelectric cylindrical shells coupling system was studied as follows:On the basis of the first-order shear deformation theory and considering the positive and inverse piezoelectric effects,a unified dynamic model of functionally graded piezoelectric material cylindrical shells with arbitrary thickness under general boundary conditions is established.Expands the displacements and electric potential functions of FGPM cylindrical shell with the form of Fourier series after correction,introduces five spring stiffness coefficient k to simulate arbitrary boundary conditions and takes its additional potential energy into consideration of Lagrange energy functional.By using Rayleigh-Ritz method,the dynamic equation of the functionally graded cylindrical shells was obtained.The method of controlling single variable was used to verify the convergence of the truncation constant M of Fourier expansions and the five spring stiffness coefficients k,the reasonable value of the five spring stiffness coefficients under different boundary conditions was determined.By comparing with the existing literature data,the reliability of calculating the natural frequency of the cylindrical shell with and without piezoelectric effect is verified,and the influence of the change of structure size,boundary condition and gradient power exponent p on the vibration characteristics of FGPM cylindrical shell is analyzed in detail.Considering the effects of the internal fluid,whose kinetic energy is incorporated into the Lagrangian energy functional.The unknown Fourier coefficients are obtained by using Rayleigh Ritz method,and the characteristic equation of vibration of fluid-filled FGPM cylindrical shell is obtained.Compared with the dimensionless frequency results calculated in the literature under the conditions of both fluid-filled and fluid-conveyed isotropic cylindrical shell,the reliability of the method has be verified,and the vibration characteristics and hydrodynamic pressure of fluid-conveyed FGPM cylindrical shell are analyzed in detail.An external controlling voltage was applied to the fluid-conveyed FGPM cylindrical shell,the potential difference generated by the inner and outer walls was converted into energy and incorporated into the Lagrangian energy functional.The forced response of the coupling system of the fluid-conveyed FGPM cylindrical shell was obtained by using the Rayleigh-Ritz method.On this basis,the dynamic characteristics of fluid-filled FGPM cylindrical shells under forced vibration are studied in depth.