• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.989-993
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• 2001

This paper deals with the free vibrations of horizontally curved beams supported by non-homogeneous elastic foundation. Taking into account the effects of rotatory inertia and shear deformation, differential equations governing the free vibrations of such beams are derived, in which the linear elastic foundation is considered as the non-homogeneous foundation. Differential equations are solved numerically to calculate natural frequencies. In numerical examples, the parabolic curved member is considered. The parametric studies are conducted and the lowest four frequency parameters are reported in tables and figures as the non-dimensional forms.

• Journal of KSNVE
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• v.4 no.4
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• pp.451-457
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• 1994

A numerical method is presented to obtain natural frequencies and mode shapes of uniform elastic beams with static deflections due to dead loads. The differential equation governing the free vibration of beam taken into account the static deflection due to deal loads is derived and solved numerically. The hinged-hinged, clamped-clamped and clamped-hinged end constraints are applied in the numerical examples. As the numerical results, the lowest three nondimensional frequency parameters are reported as functions of nondimensional system parameters; the load parameters, and the slenderness rations. And some typical mode shapes of free vibrations are also presented in figures.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.995-999
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• 2001

This paper deals with the free vibrations of arches with general boundary condition. Based on the dynamic equilibrium equations of a arch element acting the stress resultants and the inertia forces, the governing differential equation is derived for the in-plane free vibration of such arches. Differential equations are solved numerically to calculate natural frequencies. In numerical examples, the parabolic arch is considered. The effects of the arch rise to span length ratio, the slenderness ratio, the vertical spring coefficient and the rotational spring coefficient on the natural frequencies are analyzed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.1
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• pp.66-73
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• 2011

This paper deals with free vibrations of the tapered beams with the constant surface area. The surface area of the objective beams are always held constant regardless shape functions of the cross-sectional depth. The shape functions are chosen as the linear and parabolic ones. Ordinary differential equations governing free vibrations of such beams are derived and solved numerically for determining the natural frequencies. In the numerical examples, hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. As the numerical results, the relationships between non-dimensional frequency parameters and various beam parameters such as section ratio, surface area ratio, end constraint and taper type are reported in tables and figures. Especially, section ratios of the strongest beam are calculated, under which the maximum frequencies are achieved.

• Computational Structural Engineering
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• v.9 no.1
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• pp.133-139
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• 1996

In this paper, an approximate method is developed to obtain the natural frequencies of the out of plane vibration of circular curved beams. The governing differential equations are derived using the dynamic equilibrium equations with the Timoshenko theory, and solved numerically. The Runge-Kutta method and Regula-Falsi method are used to integrate the differential equations and to determine the natural frequencies, respectively. In numerical examples, the hinged-hinged and clamped-clamped end constraints are considered. For each case, the four lowest natural frequencies are reported as functions of four non-dimensional system parameters.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.423-428
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• 2002

A numerical method is presented to obtain natural frequencies and mode shapes of tapered beams with static deflections due to self-weight. The differential equation governing the free vibrations of beam taken into account the static deflection due to self-weight is derived and solved numerically. The hinged-hinged, clamped-clamped and clamped-hinged and clamped-free end constraints are applied in the numerical examples. As the numerical results, the lowest three natural frequencies versus distributed slenderness ratio and section ratio are reported in figures. And for the comparison purpose, the typical mode shapes with the effects of static deflection are presented in figures.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.4
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• pp.661-669
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• 1999

이 논문은 탄성지반위에 놓인 원호형 곡선보의 자유진동에 관한 연구이다. 회전관성 및 전단변형을 고려하여 두 개의 매개변수로 표현되는 탄성지반위에 놓인 원호형 곡선보의 자유진동을 지배하는 미분방정식을 유도하고, 이를 수치적분기법과 시행착오적 행렬값탐사법이 결합된 수치해석기법으로 해석하였다. 회전-회전, 회전-고정 및 고정-고정의 단부조건을 갖는 곡선보의 최저차모드 3개의 고유진동수를 산출하였다. 곡선보의 수평높이 지간길이비, Winkler 지반계수, 전단지반계수에 따른 고유진동수 변화를 분석하였으며, 회전관성 및 전단변형의 영향을 고찰하였다.

• Explosives and Blasting
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• v.31 no.1
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• pp.64-75
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• 2013

This case study deals with an excavation blasting carried out at "Sooseo-Pyeongtek ${\bigcirc}$-${\bigcirc}$ section construction site" in the vicinity of residential area. Originally, the sequential blasting (multi-stage blasting) using electric detonators was planed in this area. However, there was a concern that the sequential blasting method could increase the construction cost by delaying the construction period due to possible complaints from local residents. As an alternative, electronic deck blasting technique was taken in order to meet the ground vibration regulation (0.2cm/s, in apartment area) and to keep the construction schedule. The performance of the electronic deck charge blasting was two times better than the sequential blasting with electric detonators and the level of ground vibration was also within the regulatory value (0.2cm/s). In particular, it was shown that the use of electronic detonater eDevII, which was developed for tunnel, could provide more convenient and electrically safer working condition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1496-1502
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• 2012

The fuel pump mounted on the engine in the vehicle is consist of the outer and inter rotors, and which inhales fuel from the inlet port and supplies it to the outlet port. In this study, it is carried out the analysis and test of the fuel pump with rotors to evaluate its performance. It is analyzed the flow characteristics of the fuel pumps with numerical simulation in their inlet-outlet angles of 0, 15, 30 degree. After it is determined whether it has the best flow characteristics, its vibration characteristics is analyzed. The flow rate of a pump in the inlet-outlet angles of 0 degree is 191.0 LPH(Liter per hour) which is the largest. and its vibration is calculated to be 0.866 $^m/s^2$. In the results of vibration test, it is known that the vibration of the research pump is smaller than that of the existing one. And the natural frequencies of two pumps is nearly same. Therefore it is known that the performance of the research pump is superior.

• Journal of KSNVE
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• v.5 no.3
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• pp.413-421
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• 1995

Synchrotron light source building of the accelerator has stringent vibration limits since the performance of the optical devices and electronic equipments in the laboratory is strongly influenced by the vibrations of the building. In this study, vibrations of the synchrotron light source building are estimated using experimental modal analysis and force response simulation technique. Dynamic properties of the building are identified from the modal parameters and vibration responses are predicted from the force response simulation. A double anti vibration system is designed and applied to the HVAC equipments and it has been shown that the measured vibrations of the building with the double anti vibration system satisfy the vibration criteria.