• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.7
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• pp.591-598
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• 2011

This paper presents dynamic analysis of FCEV(fuel cell electric vehicle) turbo blower. To analyze the dynamic characteristics of turbo blower, FEA(finite element analysis) and experimental test are performed. Evaluations of stress safety for rotor sleeve and impeller due to rotational force and shrink fit are performed. Rotor dynamic analysis is conducted by Campbell diagram and structure vibration analyses are performed using FEA and experimental test. Through these results, noise sources of turbo blower are verified.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.11
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• pp.1111-1117
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• 2008

During the dynamic analysis of a system, the Coulomb friction law is emploved to calculate the friction force. Since the static friction coefficient is only employed during the zero relative velocity, it is impractical to employ the coefficient during the dynamic analysis. To calculate the static friction force, therefore, some friction models have been developed. In this study, the integration stability and the accuracy of the models are investigated with some numerical examples. The effect of time step size during the numerical integration is also investigated. The numerical study shows that the friction model employed for most commercial codes is not as good as the one proposed in this study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6A
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• pp.607-616
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• 2009

In this paper, a method is proposed to accurately and efficiently estimate the equivalent added mass of hydro-dynamic pressure on dam floodgates subjected to earthquake loading. The present method is based on a relatively-simple procedure using on-site vibration measurement and finite element frequency analysis, which is sufficiently practical to be used in the earthquake resistance performance evaluation of dam floodgates.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.609-612
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• 1997

This paper deals with in-plane vibration analysis of curved beams. The exact dynamic element method is applied to obtain the dynamic model for curved beams. Numerical examples are provided to validate the proposed modeling and analysis method. The numerical results show that the proposed method is useful for the dynamic analysis of curved beams.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.333-339
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• 2015

In this paper, the surface settlement resulted from the shallow TBM tunnelling has been numerically simulated. TBM tunnelling is especially used in urban area to avoid serious vibration and noise caused by explosion in NATM. Surface settlement is one of the most important problems encountered in all tunnelling and critical in urban areas. In this study, face vibration of TBM excavation is considered to estimate surface settlement trend according to TBM extrusion. The dynamic excavation forces are calculated by total torque on the TBM cutterhead in mixed-face of soil and weathered rock condition with shallow depth. A 3-dimensional FDM code is employed to simulate TBM tunnelling and mechanical-dynamic coupling analysis is performed. The 3D numerical analysis results showed that dynamic settlement histories and trend of surface settlement successfully. The maximum settlement occurred at the excavation point located at 2.5D behind the face, and the effect of face vibration on the surface settlement was verified in this study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.109-114
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• 2007

Analytical method to analyze the effect of tolerance on the modal characteristic of multi-body systems in dynamic equilibrium position is suggested in this paper. Monte-Carlo Method is conventionally employed to perform the tolerance analysis. However, Monte-Carlo Method spends too much time for analysis and has a greater or less accuracy depending on sample condition. To resolve these problems, an analytical method is suggested in this paper. By employing the sensitivity information of mass, damping and stiffness matrices, the sensitivities of damped natural frequencies and the transfer function can be calculated at the dynamic equilibrium position. The effect of tolerance on the modal characteristic can be analyzed from tolerance analysis method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.5
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• pp.1439-1446
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• 1991

본 연구에서는 동적영향계수의 축차전달에 그 개념을 두고 있는 전달영향계수 법을, 2층 원판구조물의 자유진동해석애 적용해서, 그 알고리즘을 정식화 하고 전달매 트릭스법과 비교 검토하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.8
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• pp.945-951
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• 2012

In this study, we analyze the static and dynamic characteristics of a bulk-cement trailer with a simpler structure that carries powders. The commercial software ANSYS is used to prepare a detailed three-dimensional model of the chassis frame and tank body that bear most of the load of a bulk-cement trailer for the finite element analysis. Modal analysis is conducted to examine the dynamic characteristics of the trailer body, and static analysis shows weak links in the structure. Finally, we propose a method to increase the strength of vulnerable areas and to reduce the weight of the trailer by applying the Taguchi method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1134-1139
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• 2003

Vibration problems are an intrinsic characteristic in a washing machine owing to rotation working mechanism. Therefore, a right comprehension of working principle and the analysis on dynamic behavior of a washing machine is essential to design anti-vibration or vibration reduction. In this paper, we choose two kinds of a washing machine: a suspension type pulsator/drum type washing machine. Each the structure and working principle of a washing machine is discussed briefly and the dynamic behavior of it is investigated, then, the vibration detection problems of transient or excessive vibration is tented in each category. Some vibration experimented results in a washing machine are presented also.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.7 s.124
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• pp.579-586
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• 2007

Analytical method to analyze the effect of tolerance on the modal characteristic of multi-body systems in dynamic equilibrium position is suggested in this paper. Monte-Carlo method is conventionally employed to perform the tolerance analysis. However, Monte-Carlo method spends too much time for analysis and has a greater or less accuracy depending on sample condition. To resolve these problems, an analytical method is suggested in this paper. Sensitivity equations for damped natural frequencies and the transfer function are derived at the dynamic equilibrium position. By employing the sensitivity information of mass, damping and stiffness matrices, the sensitivities of damped natural frequencies and the transfer function can be calculated.