The Experts below are selected from a list of 2943 Experts worldwide ranked by ideXlab platform
Francesco Tornabene - One of the best experts on this subject based on the ideXlab platform.
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2 d differential quadrature solution for vibration analysis of functionally graded conical cylindrical shell and Annular Plate structures
Journal of Sound and Vibration, 2009Co-Authors: Francesco Tornabene, Erasmo Viola, Daniel J InmanAbstract:This paper focuses on the dynamic behavior of functionally graded conical, cylindrical shells and Annular Plates. The last two structures are obtained as special cases of the conical shell formulation. The first-order shear deformation theory (FSDT) is used to analyze the above moderately thick structural elements. The treatment is developed within the theory of linear elasticity, when materials are assumed to be isotropic and inhomogeneous through the thickness direction. The two-constituent functionally graded shell consists of ceramic and metal that are graded through the thickness, from one surface of the shell to the other. Two different power-law distributions are considered for the ceramic volume fraction. The homogeneous isotropic material is inferred as a special case of functionally graded materials (FGM). The governing equations of motion, expressed as functions of five kinematic parameters, are discretized by means of the generalized differential quadrature (GDQ) method. The discretization of the system leads to a standard linear eigenvalue problem, where two independent variables are involved without using the Fourier modal expansion methodology. For the homogeneous isotropic special case, numerical solutions are compared with the ones obtained using commercial programs such as Abaqus, Ansys, Nastran, Straus, Pro/Mechanica. Very good agreement is observed. Furthermore, the convergence rate of natural frequencies is shown to be very fast and the stability of the numerical methodology is very good. Different typologies of non-uniform grid point distributions are considered. Finally, for the functionally graded material case numerical results illustrate the influence of the power-law exponent and of the power-law distribution choice on the mechanical behavior of shell structures.
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free vibration analysis of functionally graded conical cylindrical shell and Annular Plate structures with a four parameter power law distribution
Computer Methods in Applied Mechanics and Engineering, 2009Co-Authors: Francesco TornabeneAbstract:Based on the First-order Shear Deformation Theory (FSDT) this paper focuses on the dynamic behavior of moderately thick functionally graded conical, cylindrical shells and Annular Plates. The last two structures are obtained as special cases of the conical shell formulation. The treatment is developed within the theory of linear elasticity, when materials are assumed to be isotropic and inhomogeneous through the thickness direction. The two-constituent functionally graded shell consists of ceramic and metal. These constituents are graded through the thickness, from one surface of the shell to the other. A generalization of the power-law distribution presented in literature is proposed. Two different four-parameter power-law distributions are considered for the ceramic volume fraction. Some material profiles through the functionally graded shell thickness are illustrated by varying the four parameters of power-law distributions. For the first power-law distribution, the bottom surface of the structure is ceramic rich, whereas the top surface can be metal rich, ceramic rich or made of a mixture of the two constituents and on the contrary for the second one. Symmetric and asymmetric volume fraction profiles are presented in this paper. The homogeneous isotropic material can be inferred as a special case of functionally graded materials (FGM). The governing equations of motion are expressed as functions of five kinematic parameters, by using the constitutive and kinematic relationships. The solution is given in terms of generalized displacement components of the points lying on the middle surface of the shell. The discretization of the system equations by means of the Generalized Differential Quadrature (GDQ) method leads to a standard linear eigenvalue problem, where two independent variables are involved without using the Fourier modal expansion methodology. Numerical results concerning six types of shell structures illustrate the influence of the power-law exponent, of the power-law distribution and of the choice of the four parameters on the mechanical behaviour of shell structures considered.
M H Yas - One of the best experts on this subject based on the ideXlab platform.
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free vibration analysis of functionally graded Annular Plates by state space based differential quadrature method and comparative modeling by ann
Composites Part B-engineering, 2012Co-Authors: A Jodaei, Mostafa Jalal, M H YasAbstract:Abstract This paper deals with three-dimensional analysis of functionally graded Annular Plates through using state-space based differential quadrature method (SSDQM) and comparative behavior modeling by artificial neural network (ANN) for different boundary conditions. The material properties are assumed to have an exponent-law variation along the thickness. A semi-analytical approach which makes use of state-space method in thickness direction and one-dimensional differential quadrature method in radial direction is used to obtain the vibration frequencies. The state variables include a combination of three displacement parameters and three stress parameters. Numerical results are given to demonstrate the convergency and accuracy of the present method. Once the semi-analytical method is validated, an optimal ANN is selected, trained and tested by the obtained numerical results. In addition to the quantitative input parameters, support type is also considered as a qualitative input in NN modeling. Eventually the results of SSDQM and ANN are compared and the influence of thickness of the Annular Plate, material property graded index and circumferential wave number on the non-dimensional natural frequency of Annular functionally graded material (FGM) Plates with different boundary conditions are investigated. The results show that ANN can acceptably model the behavior of FG Annular Plates with different boundary conditions.
Liu Zhigang - One of the best experts on this subject based on the ideXlab platform.
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a numerical solution for vibration analysis of composite laminated conical cylindrical shell and Annular Plate structures
Composite Structures, 2014Co-Authors: Xie Xiang, Jin Guoyong, Li Wanyou, Liu ZhigangAbstract:Abstract This paper focuses on the free vibration analysis of composite laminated conical, cylindrical shells and Annular Plates with various boundary conditions based on the first order shear deformation theory, using the Haar wavelet discretization method. The equations of motion are derived by applying the Hamilton’s principle. The displacement and rotation fields are expressed as products of Fourier series for the circumferential direction and Haar wavelet series and their integral along the meridional direction. The constants appearing from the integrating process are determined by boundary conditions, and thus the equations of motion as well as the boundary condition equations are transformed into a set of algebraic equations. Then natural frequencies of the laminated shells are obtained by solving algebraic equations. Accuracy, stability and reliability of the current method are validated by comparing the present results with those in the literature and very good agreement is observed. Effects of some geometrical and material parameters on the natural frequencies of composite shells are discussed and some representative mode shapes are given for illustrative purposes. Some new results for laminated shells are presented, which may serve as benchmark solutions.
Tiangui Ye - One of the best experts on this subject based on the ideXlab platform.
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three dimensional vibration analysis of thick functionally graded conical cylindrical shell and Annular Plate structures with arbitrary elastic restraints
Composite Structures, 2014Co-Authors: Zhu Su, Tiangui YeAbstract:Abstract In the present work, a three-dimensional vibration analysis of thick functionally graded conical, cylindrical shell and Annular Plate structures with arbitrary elastic restraints is presented. The last two structures are obtained as special cases of the conical shell. The effective material properties of functionally graded structures vary continuously in the thickness direction according the general four-parameter power law distributions in terms of volume fraction of constituents, and are estimated by Voigt’s rule of mixture. The exact solution is obtained by means of variational principle in conjunction with modified Fourier series which is composed of a standard Fourier series and some auxiliary functions. Validity and accuracy of the current method are demonstrated by comparing the present solutions with existing results. Numerous new results are given for functionally graded conical, cylindrical shells and Annular Plates with various boundary conditions including classical and elastic boundary conditions. Parametric investigations are carried out to study the effects of geometrical parameter, boundary conditions and material profiles on free vibration of functionally graded structures.
Qingshan Wang - One of the best experts on this subject based on the ideXlab platform.
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a unified power series method for vibration analysis of composite laminate conical cylindrical shell and Annular Plate
Structures, 2021Co-Authors: Dongyan Shi, Qingshan WangAbstract:Abstract In this article, the power series method is adopted to investigate the free vibration characteristics of the composite laminated conical, cylindrical shell, and Annular Plate with arbitrary boundary conditions by the wave based matrix. By the first-order shear deformation shell theory, the governing equation of the composite laminated structure is established. The displacement and moment variables are transformed as the power series function form. Through the introduction of the boundary conditions and the continuous condition between the adjacent segments, the total matrix of the composite structure is established. Searching the zero locations of the total matrix determinant by the bisection method, the natural frequencies of the composite laminated structure under arbitrary boundary conditions are obtained. To further verify the correctness of the solutions by the presented method, some numerical examples are established. From the comparison of the solutions by the presented method and the results in some reported literature and experimental studies, the calculation accuracy is verified. Furthermore, the effect of the geometric parameters and material constants, such are elastic restrained spring stiffness constants, the angle between the shell surface and axis, length to the radius ratios, and modulus ratios, on the free vibration characteristics of the composite laminated structure, have been discussed. The advantage of the presented method is high calculation accuracy, simple matrix assembly, and convenient replacement of boundary conditions. Furthermore, some new numerical solutions are presented in this paper to provide the basic foundation for subsequent research.
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a simplified Plate theory for vibration analysis of composite laminated sector Annular and circular Plate
Thin-walled Structures, 2019Co-Authors: Hong Zhang, Dongyan Shi, Rupeng Zhu, Qingshan WangAbstract:Abstract A unified analysis model for vibration characteristics of composite laminated Annular sector Plate, circular sector Plate, Annular Plate and circular Plate with various elastic boundary conditions is established based on the simplified Plate theory (SPT) and two-dimensional (2D) improved Fourier-Ritz method. It has significant advantages in the study of free and forced vibration of thin-to-moderately thick rotary composite laminated Plates. Under the current framework, the displacement admissible functions of the rotary Plate are generally expressed as superposition of simple periodic functions, which includes the multiplication of two cosine functions and two complementary polynomials. The introduction of these polynomials can effectively eliminate jumping or discontinuity at the boundaries. The vibration characteristics of the rotary Plate can be obtained by Rayleigh-Ritz energy technique. The present method shows fast convergence and good accuracy. The parameterization study on geometric parameters, material parameters and boundary conditions has been carried out to systematically reveal the vibration characteristics of rotary composite laminated Plates, which can be the benchmark for the future research.
