• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.12 s.117
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• pp.1231-1237
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• 2006

The vibration of a running railway vehicle can be classified on lateral, longitudinal and vertical motions. The important factor on the stability and ride quality of a railway vehicle is the lateral motion. The contact between wheel and rail with conicity influences strongly on the lateral motion. In this study, an experiment for the vibration of a running railway vehicle was performed using a of the scale model of a railway vehicle. Also, the effects on the car-body, bogie and wheelset were examined for the weight and the stiffness of the second suspension system. The experimental results showed that the lateral vibration increases as the wheel conicity and stiffness of the second suspension system increase. And the lateral vibration of the bogie increases as the mass ratio between car-body and bogie increases. Also, the lateral vibration of the wheel becomes high at low speed, while the wheel of 1/20 conicity makes severe vibration at high speed running.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.643-646
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• 2009

This study was conducted to simulate the influence of vibration associated with cycling on the body. In this simulation the human model that the riding on a bicycle which have suspension and non-suspension front forks was used. And to arouse impact two kind of bump, 50mm height of radical raised spot and 150mm height of slow raised spot, were used. The vertical displacement of head, the vertical acceleration of head and the torque of neck joint were analysed. The results say that the function of shock absorbing was grater when passing though a 50mm height of radical raised spot then a 150mm height of slow raised spot.

• Journal of KSNVE
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• v.10 no.6
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• pp.1022-1028
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• 2000

This paper presents a modeling method for the vibration analysis of rotating cantilever beams considering the elastic foundation effect. Mass and stiffness matrices are derided explicitly by considering coupling effect between stretching and bonding motion. Numerical results show that the bending direction elastic foundation stiffness influences the vibration characteristics significantly in practical range of beam configuration. The ranges of elastic foundation stiffness to avoid the dynamic buckling are also presented. The method presented in this paper can be used to predict the variations of natural frequencies of rotating cantilever beams with elastically restrained root.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.600-603
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• 2005

In this paper we studied about the effect of the double cracks on the dynamic behavior of a simply supported beam. The equation of motion is derived by using Lagrange's equation and analyzed by numerical method. The simply supported beam is modeled by the Euler-Bernoulli beam theory. The crack section is represented by a local flexibility matrix connecting three undamaged beam segments. The influences of the crack depth and position of each crack on the vibration mode and the natural frequencies of a simply supported beam are analytically clarified. The theoretical results are also validated by a comparison with experimental measurements.

• Coupled systems mechanics
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• v.10 no.1
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• pp.61-77
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• 2021

The porosity of functionally graded materials (FGM) can affect the static and dynamic behavior of plates, which is important to take this aspect into account when analyzing such structures. The present work aims to study the effect of the distribution shape of porosity on the free vibration response of simply supported FG plate reposed on the Winkler-Pasternak foundation. A refined theory of shear deformation is expanded to study the influence of the distribution shape of porosity on the free vibration behavior of FG plates. The findings showed that the distribution shape of porosity significantly influences the free vibration behavior of thick rectangular FG plates for small values of Winkler-Pasternak elastic foundation parameters.

• Steel and Composite Structures
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• v.20 no.2
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• pp.227-249
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• 2016

The objective of this work is to present a zeroth-order shear deformation theory for free vibration analysis of functionally graded (FG) nanoscale plates resting on elastic foundation. The model takes into consideration the influences of small scale and the parabolic variation of the transverse shear strains across the thickness of the nanoscale plate and thus, it avoids the employ use of shear correction factors. Also, in this present theory, the effect of transverse shear deformation is included in the axial displacements by using the shear forces instead of rotational displacements as in available high order plate theories. The material properties are supposed to be graded only in the thickness direction and the effective properties for the FG nanoscale plate are calculated by considering Mori-Tanaka homogenization scheme. The equations of motion are obtained using the nonlocal differential constitutive expressions of Eringen in conjunction with the zeroth-order shear deformation theory via Hamilton's principle. Numerical results for vibration of FG nanoscale plates resting on elastic foundations are presented and compared with the existing solutions. The influences of small scale, shear deformation, gradient index, Winkler modulus parameter and Pasternak shear modulus parameter on the vibration responses of the FG nanoscale plates are investigated.

• Advances in aircraft and spacecraft science
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• v.7 no.4
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• pp.291-308
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• 2020

In this paper, a numerical method is utilized to study the effect of a new vibration absorber on vibration response of the stiffened functionally graded (SFG) cylindrical shell under a couple of axial and transverse compressions. The material composition of the stiffeners and shell is continuously changed through the thickness. The vibration absorber consists of a mass-spring-damper system which is connected to the ground utilizing a linear local damper. To simplify, the spring element of the vibration absorber is called global potential. The von Kármán strain-displacement kinematic nonlinearity is employed in the constitutive laws of the shell and stiffeners. To consider the stiffeners in the model, the smeared stiffener technique is used. After obtaining the governing equations, the Galerkin method is applied to discretize the nonlinear dynamic equation of system. In order to find the nonlinear vibration responses, the fourth order Runge-Kutta method is utilized. The influence of the stiffeners, the dynamic absorber parameters on the vibration behavior of the SFG cylindrical shell is investigated. Also, the influences of material parameters of the system on the vibration response are examined.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.693-695
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• 2007

This study describes the proposed methods for constructing the residential section which satisfies quiet environment and scenery at the same time. For the purpose of achieving this objective, the influences of house arrangement, house skyline change, soundproofing facility installation, etc. on traffic noise environment and scenery are compared using document investigation and computational results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.315-319
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• 2004

Static and dynamic responses of micro cantilever beam structures undertaking electrostatic forces are obtained employing Galerkin's method based on Euler beam theory. Variations of static and dynamic responses as well as resonant frequencies are estimated for several sets of beam properties and applied voltages. It is shown that the applied voltage influences the deflection and the modal characteristics significantly. Such information can be usefully employed for the design of MEMS structures.

• Structural Engineering and Mechanics
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• v.63 no.3
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• pp.401-415
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• 2017

In this article, hygro-thermo-mechanical vibration and buckling of exponentially graded (EG) nanoplates resting on two-parameter Pasternak foundations are studied using the four-unknown shear deformation plate theory. The material properties are presumed to change only in the thickness direction of the EG nanoplate according to two exponential laws distribution. The boundary conditions of the nanoplate may be simply supported, clamped, free or combination of them. To consider the small scale effect on forced frequencies and buckling, Eringen's differential form of nonlocal elasticity theory is employed. The accuracy of the present study is investigated considering the available solutions in literature. A detailed analysis is executed to study the influences of the plate aspect ratio, side-to-thickness ratio, temperature rise, moisture concentration and volume fraction distributions on the vibration and buckling of the nanoplates.