scholarly journals Stability and Bifurcation for a Simply Supported Functionally Graded Material Plate with One-to-One Internal Resonance

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Dongmei Zhang ◽  
Fangqi Chen
Keyword(s):  
Numerical Methods ◽  
Numerical Solutions ◽  
Equilibrium Points ◽  
Time Integration ◽  
Functionally Graded ◽  
Integration Scheme ◽  
Double Zero ◽  
Internal Resonances ◽  
Simply Supported ◽  
Stability And Bifurcation

Stability and bifurcation behaviors for a model of simply supported functionally graded materials rectangular plate subjected to the transversal and in-plane excitations are studied by means of combination of analytical and numerical methods. The resonant case considered here is 1 : 1 internal resonances and primary parametric resonance. Two types of degenerated equilibrium points are studied in detail, which are characterized by a double zero and two negative eigenvalues, and a double zero and a pair of pure imaginary eigenvalues. For each case, the stability regions of the initial equilibrium solution and the critical bifurcation curves are obtained in terms of the system parameters which may lead to Hopf bifurcation and 2D torus. With both analytical and numerical methods, bifurcation behaviors on damping parameters and detuning parameters are studied, respectively. A time integration scheme is used to find the numerical solutions for these bifurcation cases, and numerical results agree with the analytic predictions.

A Novel Sub-Stepping Method with Numerical Dissipation Control for Time Integration of Highly Flexible Structures

2018 ◽  
Vol 10 (10) ◽  
pp. 1850106 ◽  
Author(s):  
Saeed Mohammadzadeh ◽  
Mehdi Ghassemieh
Keyword(s):  
Equilibrium Points ◽  
Flexible Structures ◽  
Time Integration ◽  
Single Step ◽  
Numerical Dissipation ◽  
Integration Scheme ◽  
Step Method ◽  
Time Step ◽  
Time Increment ◽  
Time Integration Scheme

Sub-stepping time integration methods attempt to march each time step with multiple sub-steps. Generally, for the first sub-step, a single-step method is applied and the following sub-steps are solved using a method that utilizes the data obtained from two or three previous equilibrium points. Despite the robust stability in problems, control of numerical dissipation in sub-stepping schemes is a tough task due to applying different algorithms on a time increment. In order to overcome this insufficiency, a new sub-stepping time integration scheme, which uses two sub-steps in each time increment, is proposed. Newmark and quadratic acceleration methods are applied on the first and second sub-steps, respectively. Both methods utilize constant parameters that enable the control of numerical dissipation in the analysis. For the proposed method, the stability analysis revealed the unconditional stability region for the pertinent parameters. Additionally, the precision investigation disclosed an advantage of the proposed method with the presence of minor period elongation error. Finally, the application of the proposed method is illuminated via several numerical examples. In addition to numerical dissipation control, the proposed method proved to have an outstanding advantage over other methods in solving highly flexible structures more efficiently and more accurately.

scholarly journals Improving time integration scheme for FET analysis of power system angle stability

2020 ◽  
Vol 33 (1) ◽  
pp. 119-131
Author(s):  
Marin Mandic ◽  
Ivica Juric-Grgic ◽  
Nedjeljka Grulovic-Plavljanic
Keyword(s):  
Power System ◽  
Numerical Solutions ◽  
Time Integration ◽  
Local System ◽  
Trapezoidal Rule ◽  
Electromagnetic Transients ◽  
Integration Scheme ◽  
System Of Equations ◽  
Time Integration Scheme ◽  
Angle Stability

This paper presents improved algorithm for numerical analysis of power system angle stability achieved by improvement of the time integration when forming a local system of equations for power system finite elements (FE). Previously developed local system of equations of power system angle stability has been obtained using the generalized trapezoidal rule (? - method). Improvement of accuracy was obtained by using Heun's method. Numerical solutions obtained using Heun?s method and using the generalized trapezoidal rule are compared to Electromagnetic Transients Program (EMTP). It has been shown that Heun?s method yields the results with much higher accuracy comparing to results obtained by generalized trapezoidal rule.

scholarly journals Thermoelastic Analysis of Functionally Graded Cylindrical Panels with Piezoelectric Layers

2020 ◽  
Vol 10 (4) ◽  
pp. 1397 ◽  
Author(s):  
Yasin Heydarpour ◽  
Parviz Malekzadeh ◽  
Rossana Dimitri ◽  
Francesco Tornabene
Keyword(s):  
Thermal Loading ◽  
Differential Quadrature Method ◽  
Time Integration ◽  
Core Layer ◽  
Functionally Graded ◽  
Opening Angle ◽  
Integration Scheme ◽  
Graded Index ◽  
Piezoelectric Layers ◽  
Cylindrical Panels

We propose a coupled thermoelastic approach based on the Lord-Shulman (L-S) and Maxwell’s formulations to study the wave propagation in functionally graded (FG) cylindrical panels with piezoelectric layers under a thermal shock loading. The material properties of the FG core layer feature a graded distribution throughout the thickness and vary according to a simple power law. A layerwise differential quadrature method (LW-DQM) is combined with a non-uniform rational B-spline (NURBS) multi-step time integration scheme to discretize the governing equations both in the spatial and time domains. The compatibility conditions of the physical quantities are enforced at the interfaces to describe their structural behavior in a closed form. A validation and comparative analysis with the available literature, together with a convergence study, show the efficiency and stability of the proposed method to handle thermoelastic problems. Numerical applications are herein performed systematically to check for the sensitivity of the thermoelastic response to the material graded index, piezoelectric layer thickness, external electrical voltage, opening angle, and shock thermal loading, which would be very helpful for practical engineering applications.

scholarly journals Plastic failure zone characteristics and stability control technology of roadway in the fault area under non-uniformly high geostress: A case study from Yuandian Coal Mine in Northern Anhui Province, China

2020 ◽  
Vol 12 (1) ◽  
pp. 406-424 ◽  
Author(s):  
Yaoguang Huang ◽  
Aining Zhao ◽  
Tianjun Zhang ◽  
Weibin Guo
Keyword(s):  
Numerical Methods ◽  
Numerical Solutions ◽  
Stress Test ◽  
Pressure Coefficient ◽  
Stability Control ◽  
Failure Zone ◽  
Plastic Failure ◽  
Comparison Results ◽  
High Geostress ◽  
The Difference

AbstractIn order to explore the effective support method for deep broken roadway, based on the in situ stress test results, the analytical and numerical solutions of the stress and the range of plastic failure zone (PFZ) in a circular roadway subjected to non-uniform loads were obtained using analytical and finite difference numerical methods based on the elastoplastic theory, respectively. Their comparison results show that the analytical and numerical methods are correct and reasonable. Furthermore, the high geostress causes the stress and range of PFZ in roadway roof and floor to increase sharply while those in roadway ribs decrease. Moreover, the greater the difference of horizontal geostress in different horizontal directions is, the larger the range of PFZ in roadway roof and floor is. The shape of PFZ in roadway varies with the ratio of horizontal lateral pressure coefficient in x-direction and y-direction. Finally, according to the distribution characteristics of PFZ and range of PFZ under the non-uniformly high geostress, this paper has proposed a combined support scheme, and refined and optimized supporting parameters. The field monitoring results prove that the roadway deformation and fracture have been effectively controlled. The research results of this paper can provide theoretical foundation as well as technical reference for the stability control of deep broken roadway under non-uniformly high geostress.

Semi-Lagrangian exponential time-integration method for the shallow water equations on the cubed sphere grid

2020 ◽  
Vol 35 (6) ◽  
pp. 355-366
Author(s):  
Vladimir V. Shashkin ◽  
Gordey S. Goyman
Keyword(s):  
Shallow Water ◽  
Gravity Waves ◽  
Shallow Water Equations ◽  
Time Integration ◽  
Standard Test ◽  
Integration Scheme ◽  
Test Problems ◽  
Cubed Sphere ◽  
Lagrangian Scheme ◽  
Inertia Gravity Waves

AbstractThis paper proposes the combination of matrix exponential method with the semi-Lagrangian approach for the time integration of shallow water equations on the sphere. The second order accuracy of the developed scheme is shown. Exponential semi-Lagrangian scheme in the combination with spatial approximation on the cubed-sphere grid is verified using the standard test problems for shallow water models. The developed scheme is as good as the conventional semi-implicit semi-Lagrangian scheme in accuracy of slowly varying flow component reproduction and significantly better in the reproduction of the fast inertia-gravity waves. The accuracy of inertia-gravity waves reproduction is close to that of the explicit time-integration scheme. The computational efficiency of the proposed exponential semi-Lagrangian scheme is somewhat lower than the efficiency of semi-implicit semi-Lagrangian scheme, but significantly higher than the efficiency of explicit, semi-implicit, and exponential Eulerian schemes.

Thermal Post-Buckling Analysis of Functionally Graded Composite Plates with Nonlinear Aerodynamic Forces

2010 ◽  
Vol 123-125 ◽  
pp. 280-283
Author(s):  
Chang Yull Lee ◽  
Ji Hwan Kim
Keyword(s):  
Material Properties ◽  
Numerical Solutions ◽  
Virtual Work ◽  
Shear Deformation Theory ◽  
Composite Plates ◽  
Buckling Analysis ◽  
Functionally Graded ◽  
Governing Equations ◽  
Functionally Graded Composite ◽  
Post Buckling

The post-buckling of the functionally graded composite plate under thermal environment with aerodynamic loading is studied. The structural model has three layers with ceramic, FGM and metal, respectively. The outer layers of the sandwich plate are different homogeneous and isotropic material properties for ceramic and metal. Whereas the core is FGM layer, material properties vary continuously from one interface to the other in the thickness direction according to a simple power law distribution in terms of the volume fractions. Governing equations are derived by using the principle of virtual work and numerical solutions are solved through a finite element method. The first-order shear deformation theory and von-Karman strain-displacement relations are based to derive governing equations of the plate. Aerodynamic effects are dealt by adopting nonlinear third-order piston theory for structural and aerodynamic nonlinearity. The Newton-Raphson iterative method applied for solving the nonlinear equations of the thermal post-buckling analysis

scholarly journals Structural Reliability Sensitivities under Nonstationary Random Vibrations

2013 ◽  
Vol 2013 ◽  
pp. 1-21 ◽  
Author(s):  
Rita Greco ◽  
Francesco Trentadue
Keyword(s):  
Structural Reliability ◽  
Structural Parameters ◽  
Time Integration ◽  
Structural Response ◽  
Integration Scheme ◽  
Structural Systems ◽  
Frame Building ◽  
Time Integration Scheme ◽  
Noise Input ◽  
The Time Domain

Response sensitivity evaluation is an important element in reliability evaluation and design optimization of structural systems. It has been widely studied under static and dynamic forcing conditions with deterministic input data. In this paper, structural response and reliability sensitivities are determined by means of the time domain covariance analysis in both classically and nonclassically damped linear structural systems. A time integration scheme is proposed for covariance sensitivity. A modulated, filtered, white noise input process is adopted to model the stochastic nonstationary loads. The method allows for the evaluation of sensitivity statistics of different quantities of dynamic response with respect to structural parameters. Finally, numerical examples are presented regarding a multistorey shear frame building.

Sign in / Sign up

Export Citation Format

Share Document