• Proceedings of the KSME Conference
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• 2001.06c
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• pp.361-368
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• 2001

This paper introduces optimization techniques to design engine mount properties for passenger vehicle. The design targets are divided into three cases such as optimal positioning of powertrain modes, minimizing vibration of deriver's seat in idling and driving conditions. The proper models, mechanisms of vibration, and characteristics of optimization problems are discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.392-398
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• 1998

In order to check the validity of nonlinear normal modes of continuous, systems by means of the energy-based formulation, we consider a beam with a nonlinear boundary condition. The initial and boundary e c6nsl of a linear partial differential equation and a nonlinear boundary condition is reduced to a linear boundary value problem consisting of an 8th order ordinary differential equations and linear boundary conditions. After obtaining the asymptotic solution corresponding to each normal mode, we compare this with numerical results by the finite element method.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.658-663
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• 2004

The interaction between a vibrating structure and a surrounding acoustic medium determines the acoustic power propagating into the far-field. A straightforward method to reduce the radiated power is to reduce the vibration of the structure. However it is more efficient to control the modes of the structure separately since each vibration mode of the structure has different radiation efficiency. An efficient method to reduce the sound radiation in the low frequency region is proposed by reducing the radiation efficiency of the structure.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.6-11
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• 1988

Alight-weight robot arm carrying a payload is modelled as a cantilever beam with a tip mass subjected to a high speed rotation. Equations of Motion, for modal control, are represented as discrete state variable form. Digital optimal control law with observer is developed to suppress the arm vibration and control the position of the joint angle. The effects of the number of controlled modes, weighting factors of the performance index, reference rotation time, and sampling time on the control performance are analyzed by computer simulation and experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.345.2-345
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• 2002

This paper focuses on the formulation and validation of an automatic strategy for the selection of the locations and directions of strain gauges to capture at best the modal response of a blade in a series of modes. These locations and directions are selected to render the strain measurements as robust as possible with respect to random mispositioning of the gauges and gauge failures. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.385.1-385
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• 2002

Operational Modal Analysis also known as Ambient Modal Analysis has an increasing interest in mechanical cngineering. Especially on big structures where the excitation and not less important the determination of the forces is most often a problem. In a structure like a wind turbine wing where the modes occur both close in frequency and bi-directional the Ambient excitation has big advantages. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.837-842
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• 2000

Reverberation time is the well known theory and widely used in commercial apparatus to get reverberation time. However large fluctuation in low frequency region occurs in a small cabin due to superposition of a few modes. This paper investigates this phenomena in terms of modal density in frequency domain and suggests a method to get lower limit of reverberation time using the integration of the time-SPL diagram. The suggestion is confirmed by simulation and shows reasonable results to get lower limit of reverberation time and maximum absorbing power in the cabin.

• Journal of KSNVE
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• v.9 no.5
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• pp.928-935
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• 1999

Vertical pumps are widely used owing to the fact that they occupy small floor space. In this type of pumps, however, the vibrational problems are very important, since, in many cases, they have less stiffness in comparison with lateral pumps. This study presents a simple solution method for calculating the natural frequencies and modes of vertical pumps. In this study, a mode of a vertical pump was developed and the nondimensional parameters for the vibrational characteristics of it were determined. Added mass was calculated for the effects of water and the transfer matrix method was used.

• Wind and Structures
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• v.18 no.4
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• pp.457-471
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• 2014

A summary of the main results from an international comparative study for the high-frequency base balance is given. Two buildings were specified - a 'basic' and an 'advanced' building. The latter had more complex dynamic response with coupled modes of vibration. The predicted base moments generally showed good agreement amongst the participating groups, but less good agreement was found for the roof accelerations which are dominated by the resonant response, and subject to measurement errors for the generalized force spectra, to varying mode shape correction techniques, and different methods used for combining acceleration components.

• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1061-1068
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• 2003

The correlation between the water and N-methylacetamide (NMA) intramolecular vibrational frequencies and the hydrogen-bond length in a variety of NMA-H₂O and NMA-D₂O complexes was investigated by carrying out ab initio calculations. As the hydrogen-bond length decreases, the frequencies of bending and stretching modes of the hydrogen-bonding water increases and decreases, respectively, and the amide I and II (III) mode frequencies of the NMA decreases and increases, respectively. In this paper, correlation maps among the amide (I, II, and III) modes of NMA and three intramolecular water modes are thus established, which in turn can be used as guidelines for interpreting two-dimensional vibrational spectra of aqueous NMA solutions.