Sensitivity analysis of free torsional vibration frequencies of thin-walled i-beam resting on elastic foundation

1992 ◽  
Vol 13 (5) ◽  
pp. 399-408 ◽  
Author(s):  
Bożena B. Budkowska ◽  
Czestaw Szymczak
Keyword(s):  
Sensitivity Analysis ◽  
Elastic Foundation ◽  
Torsional Vibration ◽  
Vibration Frequencies ◽  
Thin Walled

scholarly journals Sensitivity analysis of free torsional vibration frequencies of thin-walled laminated beams under axial load

2019 ◽  
Vol 32 (5) ◽  
pp. 1347-1356 ◽  
Author(s):  
Czesław Szymczak ◽  
Marcin Kujawa
Keyword(s):  
Sensitivity Analysis ◽  
Cross Section ◽  
Torsional Vibration ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Vibration Frequencies ◽  
Cross Sectional ◽  
First Order ◽  
Thin Walled ◽  
Frequency Changes

AbstractThe paper addresses sensitivity analysis of free torsional vibration frequencies of thin-walled beams of bisymmetric open cross section made of unidirectional fibre-reinforced laminate. The warping effect and the axial end load are taken into account. The consideration is based upon the classical theory of thin-walled beams of non-deformable cross section. The first-order sensitivity variation of the frequencies is derived with respect to the design variable variations. The beam cross-sectional dimensions and the material properties are assumed the design variables undergoing variations. The paper includes a numerical example related to simply supported I-beams and the distributions of sensitivity functions of frequencies along the beam axis. Accuracy is discussed of the first-order sensitivity analysis in the assessment of frequency changes due to the fibre volume fraction variable variations, and the effect of axial loads is discussed too.

scholarly journals The method of direct finite perturbation of numerical models for studying of the dynamic, stiffness and strength properties for thin-walled elements of engineering constructions.

2014 ◽  
Vol 2014 (4) ◽  
pp. 114-124
Author(s):  
Юрий Костенко ◽  
Yuriy Kostenko ◽  
Анатолий Чепурной ◽  
Anatoliy Chepurnoy ◽  
Александр Литвиненко ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Numerical Models ◽  
Dynamic Stiffness ◽  
Strength Properties ◽  
Test Problems ◽  
Finite Element Models ◽  
Direct Perturbation ◽  
Thin Walled

The methods of direct perturbation for finite element models of thin-walled engineering constructions for sensitivity analysis of their strength, stiffness and dynamic characteristics to the change in their thickness are proposed. The approach for prediction of distribution for natural frequencies migration as result of change in their thickness are presented. The applicability of the linearized models to determine displacements, stresses and natural frequencies slightly thinned design compared to the nominal (original) are shown. The examples of test problems are given.

scholarly journals Free oscillations of thin-walled bimetallic pipelines of large diameter on an elastic foundation

2018 ◽  
Vol 193 ◽  
pp. 02027
Author(s):  
Vladimir Sokolov ◽  
Igor Razov ◽  
Evgeniy Koynov
Keyword(s):  
Elastic Foundation ◽  
Nuclear Power ◽  
Large Diameter ◽  
Compressive Force ◽  
Free Oscillations ◽  
Working Pressure ◽  
Momentum Theory ◽  
Internal Working ◽  
Nonlinear Version ◽  
Thin Walled

In the article, solutions are obtained for a thin-walled bimetallic pipeline. Solutions are obtained, and the frequencies of free oscillations are investigated taking into account the internal working pressure, the longitudinal compressive force, and the elastic foundation. The solutions were obtained on the basis of a geometrically nonlinear version of the semi-momentum theory of cylindrical shells of the middle bend. The proposed calculations can find application in the nuclear power industry, aviation, and the petrochemical industry.

Optimizing tuned mass damper parameters to mitigate the torsional vibration of a suspension bridge under pulse-type ground motion: A sensitivity analysis

2019 ◽  
Vol 26 (11-12) ◽  
pp. 1054-1067 ◽  
Author(s):  
Seyyed Hossein Hossein Lavassani ◽  
Hamed Alizadeh ◽  
Peyman Homami
Keyword(s):  
Sensitivity Analysis ◽  
Torsional Vibration ◽  
Passive Control ◽  
Suspension Bridge ◽  
Tuned Mass Damper ◽  
Gyration Radius ◽  
Suspension Bridges ◽  
Torsional Mode ◽  
Mass Damper ◽  
Pulse Type

Suspension bridges are structures that because of their long span and high flexibility can be prone to ambient vibrations such as ground motions. They can experience high amplitude vibrations in torsional mode during an earthquake, where a vibration control strategy seems necessary. Recently, control systems have been widely used to mitigate vibration of structures. Tuned mass damper is a passive control system. Its performance and effectiveness have been verified both theoretically and practically. In this study, a tuned mass damper system is used to mitigate the torsional vibration of a suspension bridge. The Vincent Thomas suspension bridge is selected as a case study, and its response is reduced by a tuned mass damper under ten pulse-type records from 10 major worldwide earthquakes. By using sensitivity analysis, a parametric study is carried out to optimize tuned mass damper parameters, namely, mass ratio, gyration radius, tuning frequency, and damping ratio according to the maximum reduction of the response maxima. Finally, the optimum range of each parameter that can give the best performance and provide both operational and economic justification for the implementation of the project is suggested. The numerical results indicate that the optimized tuned mass damper system can substantially reduce the maximum response and vibration time.

scholarly journals Finite elements apparatus in thin-walled rods dynamics problems

2018 ◽  
Vol 245 ◽  
pp. 08007 ◽  
Author(s):  
Vladimir Rybakov ◽  
Stanislav Dyakov ◽  
Daniil Sovetnikov ◽  
Artur Azarov ◽  
Sergey Ivanov
Keyword(s):  
Natural Vibration ◽  
Steel Structures ◽  
Vibration Frequencies ◽  
Construction Engineering ◽  
Shear Theory ◽  
Mass Matrices ◽  
Element System ◽  
Mathematical Problems ◽  
Thin Walled ◽  
Dynamics Problems

The calculation of thin-walled rods is extremely relevant problem of structural mechanics and not only from the scientific standpoint, but also due to the widespread use of so-called lightweight thin-walled steel structures for construction engineering sector. Regardless of a sufficiently large number of studies connected with the statics of thin-walled rods, the dynamics of such systems have not been thoroughly studied yet. Based on one of the forward-looking theories of calculation i.e. the semi-shear theory by Slicker, the paper provides a technique for solving the dynamics problems of thin-walled rods. The stiffness and mass matrices of the finite element system are obtained for linear approximation of the form functions, and the natural vibration frequencies of the rods are calculated. The obtained solution is accomplished by the extrapolation method of estimating the accuracy of numerical methods for solving mathematical problems.

scholarly journals Torsional vibration of cracked carbon nanotubes with torsional restraints using Eringen’s nonlocal differential model

2018 ◽  
Vol 38 (1) ◽  
pp. 70-87 ◽  
Author(s):  
Mustafa Ö Yayli ◽  
Suheyla Y Kandemir ◽  
Ali E Çerçevik
Keyword(s):  
Carbon Nanotubes ◽  
Boundary Conditions ◽  
Torsional Vibration ◽  
Nonlocal Boundary ◽  
Coefficient Matrix ◽  
Vibration Frequencies ◽  
Sine Series ◽  
Differential Model ◽  
Fourier Sine ◽  
Fourier Sine Series

Free torsional vibration of cracked carbon nanotubes with elastic torsional boundary conditions is studied. Eringen’s nonlocal elasticity theory is used in the analysis. Two similar rotation functions are represented by two Fourier sine series. A coefficient matrix including torsional springs and crack parameter is derived by using Stokes’ transformation and nonlocal boundary conditions. This useful coefficient matrix can be used to obtain the torsional vibration frequencies of cracked nanotubes with restrained boundary conditions. Free torsional vibration frequencies are calculated by using Fourier sine series and compared with the finite element method and analytical solutions available in the literature. The effects of various parameters such as crack parameter, geometry of nanotubes, and deformable boundary conditions are discussed in detail.

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