Numerical analysis of flow-induced nonlinear vibrations of an airfoil with three degrees of freedom

2011 ◽  
Vol 49 (1) ◽  
pp. 110-127 ◽  
Author(s):  
Miloslav Feistauer ◽  
Jaromír Horáček ◽  
Martin Růžička ◽  
Petr Sváček
Keyword(s):  
Numerical Analysis ◽  
Degrees Of Freedom ◽  
Nonlinear Vibrations ◽  
Three Degrees Of Freedom

The Transverse Shear Effect of a New Plate Bending Finite Element Based on the Strain Approach

2018 ◽  
Vol 35 ◽  
pp. 1-10
Author(s):  
Sifeddine Abderrahmani ◽  
Toufik Maalem ◽  
Djamal Hamadi
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Transverse Shear ◽  
Degrees Of Freedom ◽  
Close Agreement ◽  
Plate Bending ◽  
Shear Effect ◽  
Thin Plate Bending ◽  
Kirchhoff Theory ◽  
Three Degrees Of Freedom

In this paper, we present a comparative study of the transverse shear effect on the plate bending. The element used is a rectangular finite element called SBRPK (Strain Based Rectangular Plate-Kirchhoff Theory-), it used for the numerical analysis of thin plate bending, and it based on the strain approach. This element has four nodes and three degrees of freedom per node (w, θx, θy). Through the numerical applications with different loading cases and boundary conditions; the numerical results obtained are in close agreement with the analytical solution.

Numerical Analysis for Galloping of Iced Quad Bundle Conductors

2012 ◽  
Vol 226-228 ◽  
pp. 30-34
Author(s):  
Jun Yan Cai ◽  
Xi Jun Liu ◽  
Su Xia Zhang
Keyword(s):  
Numerical Analysis ◽  
Degrees Of Freedom ◽  
Damping Ratio ◽  
Simplified Model ◽  
Fluid Density ◽  
Spring Stiffness ◽  
Critical Wind Velocity ◽  
Line Path ◽  
Stiffness And Damping ◽  
Three Degrees Of Freedom

In order to attain the purpose of anti-galloping, a simplified model for iced quad bundle conductors of three degrees of freedom in vertical, horizontal and torsional directions is established by means of the Hamilton principle, in which the effect of spacers stiffness and damping is considered. Based on the model, the influence of related parameters such as fluid density, damping ratio on conductor galloping amplitude and critical wind velocity is analyzed. Simultaneously, the relation curve between elastic property of spacers and conductor galloping is obtained. The results indicate that the conductor galloping can be weakened to some degree with the proper enlargement of damping ratio, the reasonable setting of spring stiffness on spacers and the avoidance of areas such as the wind outlet and windward as much as possible when choosing the line path and so on.

Numerical Analysis of the Grasp Configuration of a Planar 3-DOF Linkage-Driven Underactuated Finger

2012 ◽  
Vol 8 (2) ◽  
Author(s):  
Hamed Khakpour ◽  
Lionel Birglen
Keyword(s):  
Numerical Analysis ◽  
Dynamic Simulation ◽  
Degrees Of Freedom ◽  
Joint Angles ◽  
Final Configuration ◽  
Contact Points ◽  
Novel Method ◽  
Three Degrees Of Freedom ◽  
Underactuated Finger ◽  
Simulation Package

This paper proposes a novel method to investigate the grasp sequence of an underactuated (a.k.a. adaptive) finger with three degrees of freedom but only one actuator and find its final configuration. This method considers the magnitude and the sign of the torques generated on the phalanges of the finger through the contact points. By using these torques as indices, the algorithm calculates the values of the joint angles during the grasping sequence until the finger reaches its final configuration. To illustrate the effectiveness of this method a class of a 3-DOF adaptive finger is chosen and analyzed and then, using the proposed methodology, its grasp configuration is calculated when grasping different fixed objects. Finally, simulations are repeated using a dynamic simulation package and the obtained results are compared to the proposed method. The results show that the method can properly estimate the final configuration of the grasp.

Analysis of Nonlinear Free Vibration of Circular Plates With Cut-Outs Using R-Function Method

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
K. V. Avramov ◽  
O. Tyshkovets ◽  
K. V. Maksymenko-Sheyko
Keyword(s):  
Function Method ◽  
Degrees Of Freedom ◽  
Nonlinear Vibrations ◽  
Ritz Method ◽  
Multiple Scale ◽  
Geometrically Nonlinear ◽  
Circular Plates ◽  
Internal Resonances ◽  
Geometrically Nonlinear Vibrations ◽  
Three Degrees Of Freedom

Geometrically nonlinear vibrations of circular plate with two cut-outs are simulated by the von Karman equations with respect to displacements. The combination of the Rayleigh–Ritz method and the R-function method, which allows satisfying all boundary conditions, is applied to obtain the vibration modes of the plate. The nonlinear vibrations are expanded using these vibrations modes. The dynamical system with three degrees of freedom is derived by Galerkin method. The influence of cut-outs size on linear and nonlinear vibrations of the plate is analyzed. For different parameters of cut-outs, different internal resonances occur in the plate. The nonlinear vibrations of the system for different internal resonances are analyzed by multiple scale method.

Numerical Analysis of Dynamic Coefficients for Gas Film Face Seals

2002 ◽  
Vol 124 (4) ◽  
pp. 743-754 ◽  
Author(s):  
Yuchuan Liu ◽  
Xinmin Shen ◽  
Wanfu Xu
Keyword(s):  
Numerical Analysis ◽  
Degrees Of Freedom ◽  
Axial Direction ◽  
Spiral Groove ◽  
Gas Bearings ◽  
Damping Coefficients ◽  
Face Seals ◽  
Stiffness And Damping ◽  
Three Degrees Of Freedom ◽  
Perturbation Approximation

A numerical analysis of stiffness and damping coefficients for gas film face seals in three degrees of freedom is presented in this paper. By applying small perturbation approximation, the steady and perturbed Reynolds equations, taking account of both hydrodynamic and hydrostatic effects, are obtained and solved by finite element method. Several numerical samples, including externally pressurized annular thrust gas bearings and spiral groove thrust gas bearings, validate the model and numerical algorithm. The results show that the interactions between axial and angular perturbation are negligible. Hence, in the dynamic analysis of gas film face seals, the perturbation in three degrees of freedom can be simplified as two independent ones, an axial movement and an angular wobble around two orthogonal axes perpendicular to axial direction.

A New Strain Based Sector Finite Element for Plate Bending Problems

2017 ◽  
Vol 31 ◽  
pp. 1-13 ◽  
Author(s):  
Sifeddine Abderrahmani ◽  
Toufik Maalem ◽  
Abdallah Zatar ◽  
Djamal Hamadi
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Finite Elements ◽  
Degrees Of Freedom ◽  
Numerical Solutions ◽  
Plate Bending ◽  
Numerical Examples ◽  
Bending Problems ◽  
Thin Plate Bending ◽  
Three Degrees Of Freedom

The purpose of this paper is to present the formulation of a new sector finite element based on the strain approach for the numerical analysis of circular thin plate bending. The element is named SBSPK and has four nodes and three degrees of freedom per node (3 d.o.f./node). From several numerical examples, it is shown that convergence can be achieved with the use of only a small number of finite elements. The results obtained are compared with analytical and available numerical solutions.

scholarly journals Active Disturbance Rejection for a Three Degrees of Freedom Gyroscope

2018 ◽  
Vol 51 (13) ◽  
pp. 372-377 ◽  
Author(s):  
Juan E. Andrade García ◽  
Alejandra Ferreira de Loza ◽  
Luis T. Aguilar ◽  
Ramón I. Verdés
Keyword(s):  
Disturbance Rejection ◽  
Degrees Of Freedom ◽  
Active Disturbance Rejection ◽  
Three Degrees Of Freedom
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