Free vibration of moderately thick functionally graded parabolic and circular panels and shells of revolution with general boundary conditions

2017 ◽  
Vol 34 (5) ◽  
pp. 1598-1641 ◽  
Author(s):  
Qingshan Wang ◽  
Dongyan Shi ◽  
Qian Liang ◽  
Fuzhen Pang
Keyword(s):  
Free Vibration ◽  
Boundary Conditions ◽  
Power Law ◽  
Ritz Method ◽  
Functionally Graded ◽  
General Boundary ◽  
General Boundary Conditions ◽  
Shells Of Revolution ◽  
Content Type ◽  
Vibration Behavior

Purpose The purpose of this work is to apply the Fourier–Ritz method to study the vibration behavior of the moderately thick functionally graded (FG) parabolic and circular panels and shells of revolution with general boundary conditions. Design/methodology/approach The modified Fourier series is chosen as the basis function of the admissible functions of the structure to eliminate all the relevant discontinuities of the displacements and their derivatives at the edges, and the vibration behavior is solved by means of the Ritz method. The complete shells of revolution can be achieved by using the coupling spring technique to imitate the kinematic compatibility and physical compatibility conditions of FG parabolic and circular panels at the common meridian of θ = 0 and 2π. The convergence and accuracy of the present method are verified by other contributors. Findings Some new results of FG panels and shells with elastic restraints, as well as different geometric and material parameters, are presented and the effects of the elastic restraint parameters, power-law exponent, circumference angle and power-law distributions on the free vibration characteristic of the panels are also presented, which can be served as benchmark data for the designers and engineers to avoid the unpleasant, inefficient and structurally damaging resonant. Originality/value The paper could provide the reference for the research about the moderately thick FG parabolic and circular panels and shells of revolution with general boundary conditions. In addition, the change of the boundary conditions can be easily achieved by just varying the stiffness of the boundary restraining springs along all the edges of panels without making any changes in the solution procedure.

scholarly journals The Modified Fourier-Ritz Approach for the Free Vibration of Functionally Graded Cylindrical, Conical, Spherical Panels and Shells of Revolution with General Boundary Condition

2017 ◽  
Vol 2017 ◽  
pp. 1-32 ◽  
Author(s):  
Lijie Li ◽  
Haichao Li ◽  
Fuzhen Pang ◽  
Xueren Wang ◽  
Yuan Du ◽  
...  
Keyword(s):  
Free Vibration ◽  
Boundary Conditions ◽  
Ritz Method ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
General Boundary ◽  
General Boundary Condition ◽  
Shells Of Revolution ◽  
Fourier Cosine ◽  
Cosine Series

The aim of this paper is to extend the modified Fourier-Ritz approach to evaluate the free vibration of four-parameter functionally graded moderately thick cylindrical, conical, spherical panels and shells of revolution with general boundary conditions. The first-order shear deformation theory is employed to formulate the theoretical model. In the modified Fourier-Ritz approach, the admissible functions of the structure elements are expanded into the improved Fourier series which consist of two-dimensional (2D) Fourier cosine series and auxiliary functions to eliminate all the relevant discontinuities of the displacements and their derivatives at the edges regardless of boundary conditions and then solve the natural frequencies by means of the Ritz method. As one merit of this paper, the functionally graded cylindrical, conical, spherical shells are, respectively, regarded as a special functionally graded cylindrical, conical, spherical panels, and the coupling spring technology is introduced to ensure the kinematic and physical compatibility at the common meridian. The excellent accuracy and reliability of the unified computational model are compared with the results found in the literatures.

scholarly journals Free vibration of functionally graded parabolic and circular panels with general boundary conditions

2017 ◽  
Vol 4 (1) ◽  
pp. 52-84 ◽  
Author(s):  
Hong Zhang ◽  
Dongyan Shi ◽  
Qingshan Wang ◽  
Bin Qin
Keyword(s):  
Fourier Series ◽  
Free Vibration ◽  
Boundary Conditions ◽  
Power Law ◽  
Admissible Function ◽  
Functionally Graded ◽  
General Boundary ◽  
General Boundary Conditions ◽  
Series Method ◽  
Fourier Series Method

AbstractThe purpose of this content is to investigate the free vibration of functionally graded parabolic and circular panels with general boundary conditions by using the Fourier-Ritz method. The first-order shear deformation theory is adopted to consider the effects of the transverse shear and rotary inertia of the panel structures. The functionally graded panel structures consist of ceramic and metal which are assumed to vary continuously through the thickness according to the power-law distribution, and two types of power-law distributions are considered for the ceramic volume fraction. The improved Fourier series method is applied to construct the new admissible function of the panels to surmount the weakness of the relevant discontinuities with the original displacement and its derivatives at the boundaries while using the traditional Fourier series method. The boundary spring technique is adopted to simulate the general boundary condition. The unknown coefficients appearing in the admissible function are determined by using the Ritz procedure based on the energy functional of the panels. The numerical results show the present method has good convergence, reliability and accuracy. Some new results for functionally graded parabolic and circular panels with different material distributions and boundary conditions are provided, which may serve as benchmark solutions.

scholarly journals Static analysis of four-parameter functionally graded plates with general boundary conditions

2019 ◽  
Vol 13 (2) ◽  
pp. 12-23
Author(s):  
Hoang Thu Phuong ◽  
Tran Huu Quoc ◽  
Ho Thi Hien
Keyword(s):  
Boundary Conditions ◽  
Power Law ◽  
Material Properties ◽  
Load Distribution ◽  
Plate Theory ◽  
Ritz Method ◽  
Functionally Graded ◽  
General Boundary ◽  
Geometrical Parameters ◽  
General Boundary Conditions

In this study, the Ritz variational method is used to analyze and solve the bending problem of rectangular functionally graded material plate with general boundary conditions and subject to some types of load distribution over the entire plate domain. Based on the Kirchoff plate theory, the equilibrium equations are obtained by minimizing the total potential energy. The material properties are assumed to be graded through the thickness of the plates according to a power law with four parameters. The accuracy of the solution has been checked and validated through different comparisons to that available literature. A wide variety of examples have been carried out to reveal the influences of different geometrical parameters, FGM power law index, type of load distribution and boundary conditions on the bending responses of the plates. The results show that the gradients in material properties play an important role in determining the response of the FGM plates.Keywords: FGM; Kirchhoff plate; Ritz method; boundary conditions.

scholarly journals Free Vibration Analysis of the Unified Functionally Graded Shallow Shell with General Boundary Conditions

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Dongyan Shi ◽  
Shuai Zha ◽  
Hong Zhang ◽  
Qingshan Wang
Keyword(s):  
Free Vibration ◽  
Boundary Conditions ◽  
Vibration Analysis ◽  
Shallow Shell ◽  
Shear Deformation Theory ◽  
Free Vibration Analysis ◽  
Functionally Graded ◽  
General Boundary ◽  
Volume Distribution ◽  
General Boundary Conditions

The free vibration analysis of the functionally graded (FG) double curved shallow shell structures with general boundary conditions is investigated by an improved Fourier series method (IFSM). The material properties of FG structures are assumed to vary continuously in the thickness direction, according to the four graded parameters of the volume distribution function. Under the current framework, the displacement and rotation functions are set to a spectral form, including a double Fourier cosine series and two supplementary functions. These supplements can effectively eliminate the discontinuity and jumping phenomena of the displacement function along the edges. The formulation is based on the first-order shear deformation theory (FSDT) and Rayleigh-Ritz technique. This method can be universally applied to the free vibration analysis of the shallow shell, because it only needs to change the relevant parameters instead of modifying the basic functions or adapting solution procedures. The proposed method shows excellent convergence and accuracy, which has been compared with the results of the existing literatures. Numerous new results for free vibration analysis of FG shallow shells with various boundary conditions, geometric parameter, material parameters, gradient parameters, and volume distribution functions are investigated, which may serve as the benchmark solution for future researches.

Effect of the multiple projectile on the low-velocity impact response of CNTs reinforced beam

2020 ◽  
Vol 17 (1) ◽  
pp. 1-17
Author(s):  
Ali Sadik Gafer Qanber ◽  
Raed Salman Saeed Alhusseini ◽  
Bashar Dheyaa Hussein Al-Kasob ◽  
Manar Hamid Jasim ◽  
Mehdi Ranjbar
Keyword(s):  
Boundary Conditions ◽  
Volume Fraction ◽  
Ritz Method ◽  
Low Velocity Impact ◽  
General Boundary ◽  
General Boundary Conditions ◽  
Lagrange Equations ◽  
Low Velocity ◽  
Content Type ◽  
Velocity Impact

PurposeThe main objective of this article is to develop a theoretical formulation for predicting the response of CNTs reinforced beam under multiple impactors with general boundary conditions, using first-order shear deformation beam theory.Design/methodology/approachThe rule of mixtures is implemented to derive the material properties of the beam. The nonlinear Hertz contact law is applied for simulation between impactors and the surface of the beam. A combination of approaches includes energy method, Ritz method and generalized Lagrange equations are used to extract the matrix form of equations of motion. The time-domain solution is obtained using implementing the well-known Runge Kutta 4th order method.FindingsAfter examining the accuracy of the present method, the effects of the number of impactors include one impactor, and three impactors in various CNTs volume fraction are studied for CNTs reinforced beam with clamped-clamped, clamped-free and simply supported boundary conditions under the low-velocity impact. The most important finding of this article is that contact force and beam indentation at the middle of the beam in the case of one impactor are greater than those reported in the case of three impactors.Originality/valueThis article fulfills an identified need to study how CNTs reinforced beam behaviour with general boundary conditions under multiple low-velocity impacts can be enabled.

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