Analysis of Circumferential Free Vibration of Functionally Graded Joined Conical-cylindrical Shells
This paper focuses on analyzing the circumferential free vibration of the functionally graded joined conical-cylindrical shell to enhance the vibration performance and stability of the structure,particu-larly in the aerospace field.First,the properties of the functionally graded materials(FGMs)are described using the Voigt model and the four-parameter power function volume fraction.The energy expressions for the conical shell and cylindrical shell are derived based on the previously obtained displacement-strain rela-tionships formulated utilizing the Donnell thin shell theory.Then,artificial springs are introduced to simu-late the continuity conditions and boundary conditions.The displacement function is constructed using Chebyshev polynomials to enable a more accurate analysis of the structural response and performance.The modal frequencies of the functionally graded joined conical-cylindrical shell are calculated employing the Rayleigh-Ritz method with this displacement function.Hence,the influence of gradient exponent,bounda-ry conditions,and geometric parameters on the modal frequencies is analyzed to reveal the vibration charac-teristics of the structure.The main results indicate that increasing the volume fraction of ceramics effec-tively enhances the modal frequencies of the structure,while higher gradient exponents lead to a decrease in the modal frequencies.Stronger boundary constraints result in higher modal frequencies for the func-tionally graded joined conical-cylindrical shell.With an increase in the circumferential wave number,the influence of boundary conditions on the structural modal frequencies diminishes.The effect of boundary constraints is more pronounced on the cylindrical shell compared to the conical shell.Additionally,the axi-al spring stiffness has a more significant impact on the modal frequencies of the structure compared to the circumferential and radial spring stiffnesses.When the circumferential wave number is greater than 3,the modal frequency of the structure exhibits a linear increase with increasing shell thickness,whereas increas-ing the conical and cylindrical shell length ratio leads to a decrease in modal frequency.Finally,when the length ratio of the conical and cylindrical shell is fixed,increasing the cone angle initially results in an in-crease in the modal frequencies of the structure until it reaches a peak value,after which it starts to de-crease.
joined conical-cylindrical shellsfunctionally graded materialChebyshev polynomialmodal frequency
NETL
NSTL
万方数据
