• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.364-369
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• 1997

It is very difficult to execute the vibration analysis of a huge structure, which takes up much time and expense. In this paper we intend to make the equivalent system of a local vibration system of a huge structure with a view to improving the dynamic characteristics and reducing time and expense. First of all, upper deck structure model is maded. And we perform the vibration analysis by the Substructure Synthesis Method and execute the exciting test for the upper deck structure model, and observe the coincidences of two results to confirm the reliability of the analyzing tools used. To make the equivalent system, we give boundary condition to sub-structure that want to be modified and execute the Sensitivity Analysis Method and the Optimum Structural Modification Method. And we execute the structural modification of the equivalent system.

• Computational Structural Engineering
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• v.4 no.4
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• pp.10-13
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• 1991

현대의 건물은 초고층화 되어가기 때문에 바람이나 지진에 의한 건물의 과다진동이 일어나며 이것은 기초분리(base isolation) 방법 또는 제진장치를 설치함으로써 해결할 수가 있다. 기초분리 방법은 지진 다발 지역에서 지진에 의한 피해를 감소시키기 위하여 주로 이용되며 제진장치는 지진은 물론 바람을 받는 고층건물, 타워, 다리 등의 대형 구조물의 제진에 사용이 되며 병원, 컴퓨터센터, 그리고 반도체 공장 등 정밀한 작업이 이루어지는 곳에서의 국부적인 제진에 적용이 되고 있다. 제진장치는 수동제진장치와 능동제진장치로 대별이 되며 원리는 질량을 이용한 건물의 감쇠력을 증대시키는 데 있다. 능동제진장치를 이용한 시스템은 과다한 설치비와 운영비 뿐만 아니라 강한 바람이나 지진이 왔을 때 전력 중단이 되어 작동이 되지 않을 때가 있으므로 현재로서는 수동제진장치가 많이 이용이 되고 있다. 따라서 현재 강한 바람이나 지진에 대한 건물전체의 거동은 수동제진장치에 의하여 대처하고 약한 바람과 지진 등에 대한 국부적인 제진에는 능동제진장치를 이용하는 복합제진시스템(hybrid vibration control system)이 제시되고 있다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.662-665
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• 2010

본 연구에서는 전역적-국부적 구조건전성 모니터링을 위한 무선센서노드로서 가속도 및 임피던스 응답신호의 계측이 가능한 다기능 무선센서노드를 개발하였다. 이를 위해 첫째, 가속도 및 임피던스 응답의 계측이 가능한 다기능 무선센서노드를 설계 및 제작하였다. 둘째, 다기능 무선센서노드의 성능검증을 위하여 트러스교 모형을 대상으로 진동실험을 수행하였다. 셋째, 다기능 무선센서노드로부터 취득된 가속도 및 임피던스 응답을 이용하여 트러스 구조물의 구조 건전성 모니터링을 통해 다기능 무선센서노드의 적용성을 검증하였다.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.18 no.2
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• pp.130-137
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• 1989

본 논문은 1. 초청정기술의 현황, 2. 초청정장치의 요소기술, 3. 초청정장치의 개요, 4. 국부청정실의 기본계획에 대해 기술하고 있다. 1. 초청정기술의 현황에서는, 본 연구수행의 방향설정을 위해 미국과 일본의 관련 학${\cdot}$협회의 동향 및 최근에 발표된 논문에 근거한 초청정기술의 연구경향과 과제 등을 파악 분석했다. 2. 초청정장치의 요소기술에서는, 초청정장치 개발에 필요한 미립자제거, 환경조건과 오염제어 기술을 확립하기 위해, Filter와 System Ceiling 방식, 온${\cdot}$습도, 진동, 정전기제어 기술에 관한 문제점과 대책에 대해 검토했다. 3. 초청정장치의 개요에서는, 초청정장치로써 대표적인 클린벤취의 관련규격, 설계요점 등을 검토하여 설계를 위한 기초자료로 삼았다. 4. 국부청정실의 기본계획에서는 상기의 요소기술과 기초자료에 근거하여 본 연구를 수행하기 위한 Line 형의 클린터널 유닛의 기본계획을 수립했다.

• Explosives and Blasting
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• v.22 no.3
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• pp.43-55
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• 2004

Use term of tower style construction exceeds recently. Accordingly, according to construction safety diagnosis result, achieve removal or Improvement construction. But when work removal, must shorten shut down time. Therefore, removal method of construction to use blasting demolition of construction is very profitable. Influence construction and equipment by blasting vibration and occurrence vibration caused by felling impact. Is using disadvantageous machine removal method of construction by and economic performance by effect of such vibartion. Therefore, this research studied techniques to forecast vibartion level happened at blasting demolition and vibration reduction techniques by use a scaled model test.

• Journal of the Korean Society for Railway
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• v.17 no.5
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• pp.321-327
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• 2014

In this paper, linear dynamic equations are derived from nonlinear dynamic equations of constrained multibody systems using the QR decomposition method. The derived linear equations are applied to a railway vehicle bogie. The vibration characteristics of the railway vehicle are investigated by calculating the natural mode and transfer function of the bogie frame in relation to rail-roughness input. The main modes of the bogie were found below 35Hz, and the local modes above 198Hz. The magnitude of the vertical transfer function varied with the forward velocity due to vertical and pitch modes, which were influenced by the forward velocity. The magnitude of the lateral transfer function was negligibly small, and the mode in the longitudinal direction was excited for longitudinal transfer function regardless of the forward velocity.

• Composites Research
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• v.33 no.6
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• pp.377-382
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• 2020

The free vibration characteristics of corrugated laminated composite plates with axial stiffeners is investigated using the Rayleigh-Ritz method. The plate is stiffened by beams with open cross-section area. The equivalent homogenization model is used for the corrugated laminated composite plates. This homogenization model is treated a corrugated plate as an orthotropic plate that has different material properties in two perpendicular directions. The motion of equivalent plate is represented on the basis of the first order shear deformation theory (FSDT) to account for the effect of rotary inertia and transverse shear deformation. Stiffeners are considered as discrete elements to predict the local vibration mode to be generated by the presence of stiffeners. To validate the proposed analytical approach, natural frequencies and vibration mode shapes from the analytical method are compared with those from the FEA by ANSYS.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.1
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• pp.158-172
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• 1992

In ships and offshore structures, there are many local structures formed of thick plates and/or having the form of double wall panels. For the vibration analysis of such a kind of structures, Mindlin plate theory which includes the effects of shear deformation and rotary inertia is usually adopted. In this paper, the vibration and dynamic sensitivity analysis of Mindlin plates having the boundary conditions elastically restrained against rotation have been accomplished using the Rayleigh-Ritz method. Polynomials having the property of the Timoshenko beam functions are introduced and used as trial functions in the spatial representation of the deflection and rotations of cross sections in two directions of the plates. The results obtained by the introduced polynomials gave nearly the same numerical results as those by the Timoshenko beam functions with the remarkable reduction of computational efforts especially in the dynamic sensitivity analysis.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1994.04a
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• pp.105-112
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• 1994

In a local vibration analysis of a large steel frame, a large eigenvalue problem results. Due to computer storage and the expense of a complete solution, it is desirable to minimize the size of the resulting matrices. A new and efficient method of local vibration analysis for large steel frames is presented. It reduces the order of dynamic matrices by dynamic condensation method. Examples are given for local vibration of a plane frame. Results are compared to the complete solution of the full eigenvalue problem.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.527-534
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• 2000

Characteristics of local vibration modes of a corrugated panel are investigated by finite element analysis and modal testing. Structural modification model in the corrugation is proposed to increase the resonance frequency. This model decreases the fall by the local resonance in the transmission loss of the corrugated pallet and improves sound insulation performance. Damping effect of tile foam filled ill tile core cavity is also estimated by experiment The results of tile study offer useful information how to predict the severe local resonances in corrugations and how to prevent their undesirable effect ell the sound insulation and the vibration transmission.