Vibration analysis of doubly asymmetric, three-dimensional structures comprising wall and frame assemblies with variable cross-section

2008 ◽  
Vol 318 (1-2) ◽  
pp. 247-266 ◽  
Author(s):  
B. Rafezy ◽  
W.P. Howson
2012 ◽  
Vol 9 (1) ◽  
pp. 94-97
Author(s):  
Yu.A. Itkulova

In the present work creeping three-dimensional flows of a viscous liquid in a cylindrical tube and a channel of variable cross-section are studied. A qualitative triangulation of the surface of a cylindrical tube, a smoothed and experimental channel of a variable cross section is constructed. The problem is solved numerically using boundary element method in several modifications for a periodic and non-periodic flows. The obtained numerical results are compared with the analytical solution for the Poiseuille flow.


2013 ◽  
Vol 18 (3) ◽  
pp. 351-360 ◽  
Author(s):  
Hasan Çallıoğlu ◽  
Ersin Demir ◽  
Yasin Yılmaz ◽  
Metin Sayer

1977 ◽  
Vol 99 (2) ◽  
pp. 367-373 ◽  
Author(s):  
B. H. Walker ◽  
M. B. Friedman

A mathematical model of an oil field drill string which includes the effect of torque has been developed. The drill string can include arbitrary members with known mechanical properties. The solution gives the three-dimensional deflection curve, forces on the borehole wall, the magnitude and direction of the resultant force and slope of the deflection curve at the bit.


2011 ◽  
Vol 189-193 ◽  
pp. 4405-4408
Author(s):  
Ke Wang ◽  
Zhe Ying Wang ◽  
Xing Wei Sun

Bulge forming is a novel process aimed at common products including T-branches, cross branches and angle branches. But bulging forming has not applied for two-head abnormity-shaped hollow screw rotor reported in literature. Simulation of the bulging forming of two-head abnormity-shaped hollow screw rotor has not been reported. This paper presents a simulation of the bulge forming process of two-head abnormity-shaped hollow screw rotor using a variable cross-section solid bulging mold. Some conditions including the effect of friction, boundary conditions, contact conditions and the space motion, etc are presented. The mathematical model of three-dimensional finite element analysis has been established. The distribution of generalized plastic strain and general metal flow mode in cross section of two abnormity-shaped hollow screw rotor has been analyzed. It is an effective method for the analysis of other defects and the optimization of process parameters further.


2011 ◽  
Vol 8 (1) ◽  
pp. 155-162
Author(s):  
Yu.A. Itkulova

In the present work the three-dimensional flow of a viscous liquid described by Stokes equations is studied in a cylindrical tube and a channel of variable cross-section. A qualitative triangulation of the surface of a channel variable cross-section is constructed. The problem is solved numerically using the boundary element method in two modifications. A comparison of the method modifications for a channel of different radius of a neck, as well as for the Poiseuille flow with an analytical solution. It is found out the critical radius of the channel neck at which the vortices arise.


2020 ◽  
Vol 68 (1) ◽  
pp. 38-47
Author(s):  
Gang Wang ◽  
Wen L. Li ◽  
Wanyou Li ◽  
Zhihua Feng ◽  
Junfang Ni

A generalized analytical method is developed for the vibration analysis of Timoshenko beams with elastically restrained ends. For a beam with any variable cross section along the lengthwise direction, the finite element method is the only unified approach to handle those kinds of problems, since the analytical solutions could not be obtained by the governing equations when the cross section area and the second moment of area changing variably lengthwise. In this article, a unified approach is proposed to study the Timoshenko beam with any variable cross sections. The cross section area and second moment of area of the beam are both expanded into cosine series, which are mathematically capable of representing any variable cross section. The translational displacement and rotation of cross section are expressed in the Fourier series by adding some admissible functions which are used to handle the elastic boundary conditions with more accuracy and high convergence rate. By using Hamilton's principle, the eigenvalues and the coefficients of the Fourier series are both obtained. Some examples are presented to illustrate the excellent accuracy of this method. Analytical solutions of the vibration of the beam are achieved for different combinations of boundary conditions including classical and elastically restrained ones. The derived results can be used as benchmark solutions for testing approximate or numerical methods used for the vibration analysis of Timoshenko beams with any variable cross section.


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