Application of radial basis function-based meshless method for torsional analysis of elliptical and bone shaped-irregular sections

Author(s):  
Ram Bilas Prasad ◽  
Jeeoot Singh ◽  
Karunesh Kumar Shukla

This article presents a torsional analysis of solid elliptical, hollow circular, and actual bone sections of orthotropic and functionally graded material. The formulation of the governing equation is done using the Saint-Venant torsion theory. A classical power law is considered for the modelling of functionally graded material. Five different radial basis functions-based meshless methods are used for the discretization of the governing differential equations. MATLAB code is developed to solve the discretized partial differential equations. A convergence and validation study has been carried out to demonstrate the effectiveness and accuracy of the present method. Numerical examples for torsional rigidity and shear stresses are presented for circular, elliptical, and bone-shaped irregular sections made up of orthotropic and functionally graded materials. Finally, the proposed radial basis function-based meshless method is applied to the modelling and torsional analysis of an actual bone cross-section.

Author(s):  
Rahul Kumar ◽  
Achchhe Lal ◽  
Bhrigu Nath Singh ◽  
Jeeoot Singh

This paper presents some new and valuable numerical results for the thermo-mechanical buckling analysis of bidirectional porous functionally graded plates with uniform and non-uniform temperature rise. The strong form formulation is implemented for thermo-mechanical buckling in the framework of higher-order shear deformation theory. The material property with four schemes of porosity distribution of bidirectional porous functionally graded plate is taken by a modified power law. The governing differential equations are accomplished utilizing the principle of virtual works. The multi-quadric radial basis function is implemented for discretizing the governing differential equations. The multi-quadric radial basis function Euclidean norm is modified to analyze the square as well as rectangular plates without changing the shape parameters. Convergence and validation studies are performed to show the accuracy, effectiveness, and consistency of the present meshfree collocation method. The influence of different porosity distributions, span to thickness ratios, aspect ratios, grading index, temperature raise, boundary conditions, and porosity index on thermomechanical buckling load is evaluated. Some novel results for the bidirectional porous functionally graded plate are also enumerated that can be utilized as benchmark results for future reference.


2014 ◽  
Vol 1082 ◽  
pp. 383-386
Author(s):  
Yu Liang ◽  
Song Xiang ◽  
Wei Ping Zhao

Stress of simply functionally graded plates is predicted by the meshless method based on inverse multiquadrics radial basis function. The genetic algorithm is utilized to optimize the shape parameter of inverse multiquadrics radial basis function. The stress of simply functionally graded plates is calculated using the inverse multiquadrics with optimal shape parameter and compared with the analytical results of available literatures.


Author(s):  
J. Awrejcewicz ◽  
A. V. Krysko ◽  
S. P. Pavlov ◽  
M. V. Zhigalov ◽  
V. A. Krysko

The size-dependent model is studied based on the modified couple stress theory for the geometrically nonlinear curvilinear Timoshenko beam made from a functionally graded material having its properties changed along the beam thickness. The influence of the size-dependent coefficient and the material grading on the stability of the curvilinear beams is investigated with the use of the setup method. The second-order accuracy finite difference method is used to solve the problem of nonlinear partial differential equations (PDEs) by reducing it to the Cauchy problem. The obtained set of nonlinear ordinary differential equations (ODEs) is then solved by the fourth-order Runge–Kutta method. The relaxation method is employed to solve numerous static problems based on the dynamic approach. Eight different combinations of size-dependent coefficients and the functionally graded material coefficient are used to study the stress-strain responses of Timoshenko beams. Stability loss of the curvilinear Timoshenko beams is investigated using the Lyapunov criterion based on the estimation of the Lyapunov exponents. Beams with/without the size-dependent behavior, homogeneous beams, and functionally graded beams having the same stiffness are investigated. It is shown that in straight-line beams, the size-dependent effect decreases the beam deflection. The same is observed if the most rigid layer is located on the top of the beam. In the curvilinear Timoshenko beam, such a location of the most rigid layer essentially improves the beam strength against stability loss. The observed transition of the largest Lyapunov exponent from a negative to positive value corresponds to the transition from a precritical to postcritical beam state.


2018 ◽  
Vol 34 (3) ◽  
pp. 959-981 ◽  
Author(s):  
Nam Mai-Duy ◽  
Deepak Dalal ◽  
Thi Thuy Van Le ◽  
Duc Ngo-Cong ◽  
Thanh Tran-Cong

Mathematics ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 270
Author(s):  
Cheng-Yu Ku ◽  
Jing-En Xiao ◽  
Chih-Yu Liu

In this article, a novel radial–based meshfree approach for solving nonhomogeneous partial differential equations is proposed. Stemming from the radial basis function collocation method, the novel meshfree approach is formulated by incorporating the radial polynomial as the basis function. The solution of the nonhomogeneous partial differential equation is therefore approximated by the discretization of the governing equation using the radial polynomial basis function. To avoid the singularity, the minimum order of the radial polynomial basis function must be greater than two for the second order partial differential equations. Since the radial polynomial basis function is a non–singular series function, accurate numerical solutions may be obtained by increasing the terms of the radial polynomial. In addition, the shape parameter in the radial basis function collocation method is no longer required in the proposed method. Several numerical implementations, including homogeneous and nonhomogeneous Laplace and modified Helmholtz equations, are conducted. The results illustrate that the proposed approach may obtain highly accurate solutions with the use of higher order radial polynomial terms. Finally, compared with the radial basis function collocation method, the proposed approach may produce more accurate solutions than the other.


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