• Proceedings of the KSR Conference
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• 2011.10a
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• pp.3195-3200
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• 2011

The vibration resulting from railway operation is transmitted through the track and line structure, ground movements to adjacent buildings. As these vibration is growing, there is occurred exaggerated forces and displacements of the track and line structure and it is causing the differential settlement. It is difficult to clarify the dynamic response characteristics of trackbed because of various environmental conditions. However, track irregularity be affected by ununiformed bearing capacity and its dynamic response, study for dynamic response characteristics is required to investigate the cause of track irregularity and countermeasure. This study was intended to evaluate the numerical analysis which exam the response analysis characteristic of ground vibration by shape of cutting and embankment transition zone. The original method of analysis were have to examine variables such as directions, angles, drain conditions, linear conditions. However, In the analysis there were to consider the effect of moving loads according to directions of cutting and embankment transition zone.

• Structural Monitoring and Maintenance
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• v.3 no.2
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• pp.157-174
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• 2016

Based on classical viscoelastic damper, a brand-new damper is designed by the change of simple construction to implement vibration control for both translational vibration and rotational vibration simultaneously. Theoretic analysis has been carried out on the restoring force model and the control parameters. Two improved models are presented to obtain high simulation precision. The influence of the size, shape of the viscoelastic material, the ambient temperature and the response frequency on the vibration control effect is analyzed. The numerical results show that the new type viscoelastic damper is capable of mitigating the multi-dimensional seismic response of offshore platform and the response control effect has complicated relations with aforementioned related factors.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.455-460
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• 2012

Thirteen taxi drivers as the subject in the experiment were exposed to vertical vibration which is controlled on a rigid seat reflecting vibration on passenger vehicle. They were employed not only to get human response of objective measurement but also to make subjective evaluation of the vibration. The subjective evaluation was estimated using the absolute discomfort threshold of the controlled vibration, which was achieved with the three-down one-up method that is widely used in the field of psychophysics. As the result, apparent mass and apparent eccentric mass as objective human response tend to gradually decrease when frequency of the vibration increases. The absolute discomfort threshold was increased in case of increasing the frequency. Concludingly, the subjective discomfort evaluation is highly correlated with the objective human responses at the range of idle vibration on passenger vehicle.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.5
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• pp.422-428
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• 2012

Thirteen taxi drivers as the subject in the experiment were exposed to vertical vibration which is controlled on a rigid seat reflecting vibration on passenger vehicle. They were employed not only to get human response of objective measurement but also to make subjective evaluation of the vibration. The subjective evaluation was estimated using the absolute discomfort threshold of the controlled vibration, which was achieved with the three-down one-up method that is widely used in the field of psychophysics. As the result, apparent mass and apparent eccentric mass as objective human response tend to gradually decrease when frequency of the vibration increases. The absolute discomfort threshold was increased in case of increasing the frequency. Concludingly, the subjective discomfort evaluation is highly correlated with the objective human responses at the range of idle vibration on passenger vehicle.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.97-102
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• 2007

As environmental vibration requirements on precision equipments get more stringent, use of pneumatic vibration isolators becomes more crucial and, hence, their dynamic performance needs to be further improved. Dynamic behavior of those pneumatic vibration isolation tables is very important to both manufacturer and customer as performance specifications. Together with conventional transmissibility, transient response characteristics are another critical performance index especially when movements of components, e.g., x-y tables, of the precision equipments are very dynamic. In this paper, analysis on transient response of a pneumatic vibration isolation table loaded by a mass moving on it is presented. This is a conventional dynamics problem on a rigid body with 6 degree of freedom and a mass with another degree of freedom. How to obtain transient responses of the isolation table is described when the movements of the mass are prescribed relative to the table.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.6 s.123
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• pp.515-523
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• 2007

As environmental vibration requirements on precision equipments get more stringent, use of pneumatic vibration isolators becomes more crucial and, hence, their dynamic performance needs to be further improved. Dynamic behavior of those pneumatic vibration Isolation tables is very important to both manufacturer and customer as performance specifications. Together with conventional transmissibility, transient response characteristics are another critical performance index especially when movements of components, e.g., x-y tables, of the precision equipments are very dynamic. In this paper, analysis on transient response of a pneumatic vibration isolation table loaded by a mass moving on it is presented. This is a conventional dynamics problem on a rigid body with 6 degree of freedom and a mass with another degree of freedom. How to obtain transient responses of the isolation table is described when the movements of the mass are prescribed relative to the table.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.4
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• pp.169-178
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• 1998

In general, the response spectrum analysis method is widely used for seismic analysis of building structures, and the time history analysis is applied for computation of structural vibration caused by equipments, machines and moving loads, etc. However, compared with the response spectrum analysis method, the time history method is very complex, difficult and time consuming. In this study, the maximum responses for the vertical vibration are calculated conveniently by the response spectrum method. At first, Response spectrum and time history analysis for some earthquake excitations are carried out, and the accuracy of maximum displacements obtained from response spectrum analysis is investigated. Secondly, the process for the response spectrum analysis in excitation is calculated, and the maximum modal responses are combined by CQC method. Finally, results of the proposed method are compared with those of the time history analysis.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.533-542
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• 2000

Instrumentation and technologies are described for determining the vibration response characteristics of the pear with frequency range 5 to 320Hz. The computer program for controlling the vibration exciter and the function generator and for measuring the vibration response characteristics of the pear was developed. Mechanical properties such bioyield deformation, rupture deformation and apparent elastic modulus etc. were compared with the vibration response characteristics of the pear. The resonant frequency of the pear ranged from 53 to 102Hz and the amplitude at resonance was between 1.08 and 2.48g-rms. The resonant frequency and amplitude at resonance decreased with the increase of the sample mass, and they were slightly affected by mechanical properties such as bioyield deformation and rupture deformation. Regression analysis was performed among the relatively high correlated parameters from the results of correlation coefficient analysis.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.5
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• pp.123-130
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• 2001

The purpose of this paper is to reduce the level of idling vibration on a steering wheel. In some cases, vibration on steering wheel is amplified due to the resonance between the first natural frequency of T-beam and engine idling speed. Using SDM(structural dynamic modification) technique, T-beam is redesigned to reduce its vibration. This paper used FRF(frequency response function) synthesis technique which is entirely dependent on experiment. But this method requires lots of test efforts to enhance its reliability of design. While combining this method with an analytic method. the experimental burden, the major drawback of FRP synthesis method, can be considerably relieved. Using ana1ytic sensitivity analysis, some effective modification regions are preliminarily chosen as candidate Positions where SDM can be applied to modify T-beam\`s dynamic characteristics.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.271-276
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• 2001

Most engineers, related to soil and civil dynamic field, have been interested in the dynamic response of building transmitted from soil and rock to structure due to blasting. However it is not easy to estimate the dynamic response of structures and utilities due to blasting by using analytical method because of difficulties of soil modeling, prediction of excitation force and so on. In this paper, dynamic response analysis have been performed to predict vibration levels of structure due to blasting and the semi-empirical method. which is based on vibration measurement data. has been employed to consider blast vibration characteristics.