• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.297-302
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• 1999

평판의 일반적인 형태의 진동을 해석하기 위해서는, 외면진동뿐만이 아니라 내면진동을 해석하여야 한다. 평판 내면진동의 경우 탄성파인 종파와 전단파의 전파에 의한 영향으로 발생하며, 진동 변위, 진동 에너지, 진동 인텐시티 등의 특성들을 이해하기 위해서는 각 파동의 영향을 분리하여 낼 필요가 있다. 내면진동을 해석하기 위하여 진동 모드법을 사용할 수 있으나, 각 파동에 의한 영향을 분리하여 낼 수가 없다. 본 논문에서는 진동장을 탄성파들에 의한 영향의 합으로 나타냄으로써, 각 파동에 의한 진동 변위, 진동 에너지, 진동 인텐시티 둥의 영향들을 분리할 수 있는 해석 방법을 제안하고자 한다. 이러한 해석 방법을 이용하여 점가진력에 의하여 강제 진동하는 평판의 내면 진동장에 대한 수치 계산을 수행하였다. 결과로써 진동 변위, 진동 에너지, 진동 인텐시티 등을 이루는 탄성파들의 기여도와 특성들을 분석함으로써 본 해석기법의 유용성을 보였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.4
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• pp.469-479
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• 2001

In the present study, free vibration analysis of multi-delaminated beams is performed. In order to investigate the effects of mu1ti-delaminations on the dynamic characteristics of multi-delaminated beams, the general kinematic continuity conditions are derived from the assumption of constant curvature at the multi-delamination tip. Frequency equations of multi-delaminated beams are obtained by dividing the global multi-delaminated beam into beam segments and by imposing recurrence relation from the continuity conditions un each sub-beam. The comparisons between the results of numerical analysis obtained by finite element analysis and those of present analysis give good agreement with each other. It is shown that the effects of multi-delaminations on free vibration characteristics of laminated beams could be used to detect their sizes, types and locations from the results.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.2
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• pp.39-48
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• 1997

New form of base isolators made of steel spring coated with both natural and artficial rubber were manufactured and tested for material properties. Shaking table experiments were performed using a model structure attached with the bearings. The model structure used in the test is a 1/4 scaled steel structure, and earthquake records were used to check the lateral and vertical stability and effectiveness of the isolators. According to the results all three types of isolators turned out to be effective in reducing the acceleration induced by the earthquake vibration.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.3
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• pp.523-534
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• 2002

Free vibration and buckling analysis of multi-delaminated composite beam-columns subjected to axial compressive load is performed in the present study In order to investigate the effects of multi-delaminations on the natural frequency and the elastic buckling load of multi-delaminated beam-columns, the general kinematic continuity conditions are derived from the assumption of constant slope and curvature at the multi-dclamination tip. The characteristic equation of multi-delaminated beam-column is obtained by dividing the global multi-delauunated beam-columns into segments and by imposing recurrence relation from the continuity conditions on each sub-beam-column. The natural frequency and the elastic buck)ing load of multi-delaminated beam-columns according to the incremental load of axial compression, which is limited to the maximum elastic buckling load of sound laminated beam-column, are obtained. It is found that the sizes, locations and numbers of multi-delaminations have significant effect on natural frequency and elastic buckling load, especially the latter ones.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.306-311
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• 1995

원자로 내부구조물의 진동감시를 위한 신호로 노외 중성자 잡음을 선정하고 중성자 잡음에 실려 있는 진동모우드 성분을 신호간의 위상차에 근거하여 분리하는 새로운 방법을 제안하였다. 이 방법은 기존의 방법에 비해 계산속도가 빠르고 3개 이상의 신호에도 적용할 수 있다. 제안한 방법을 토대로 울진 1호기의 노외 중성자 잡음 신호를 채취, 분석하여 내부구조물의 진동특성을 밝히고 진동 감시의 대상이 되는 진동모우드를 분리하므로써 방법의 효율성을 검증하였다. 또 한 핵연료주기동안 주기적으로 신호를 채취, 분석하여 중성자 잡음신호의 특성이 한 핵주기동안 점차 증가하는 경향을 갖는다는 것을 밝혔다.

• Resources Recycling
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• v.5 no.3
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• pp.37-43
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• 1996

The recovery of metals from printed circuit board(PCBs) scraps was investigated by utilizing a shape sorting method.After all electronic parts mounted on the board were removed. PCBs were pulverized to particles smaller than 1 mm by aswing hammer type impact mill in order to liberate metal components. Metals were separated from nonmetalliccomponents by an inclined vibrating plate (IVP). The metal separation efficiency was measured as a function of vihrationintensity and inclined angle. The maximum efficiency was obtained when IVP was operated at the vibration intensity(Kv)of 1.40 and the inclined angle of 10". The grade of the metal components was recovered from PCBs exceeding 90% byusing IVP.0% by using IVP.

• Journal of the Korea Concrete Institute
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• v.13 no.5
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• pp.423-429
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• 2001

In this study, strength characteristics of concrete specimens subjected to horizontal continuous vibration during initial curing were investigated. As experimental variables, vibration velocity(0.25, 0.5, 1.0, 2.0, 4.0 kine) and vibration time(3, 6, 12, 24 hrs) were used. Density and segregation of the specimens were also investigated. Vibrating was started soon after placing, and strengths investigated consist of compressive strength, splitting tensile strength, and bond strength. Strengths decrease were hardly occurred at 0.25 kine vibration velocity regardless of vibration times and all strengths were increased for 3 hrs vibration at 0.5 kine vibration velocity. Density was increased for all specimens due to the vibration and there was no serious segregation under even 4 kine vibration velocity.

• Journal of Animal Environmental Science
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• v.2 no.1
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• pp.79-86
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• 1996

Solid/Liquid(S/L) separation is crucial for biological treatment of animal wastewater. Liquid portion from S/L separation has less BOD-load and proper post-strip treatment can be obtained. Screen or declined sieve was normally used to separate the solid parts. For better separating efficiency a vibration and a cylindrical separator were constructed and tested. The results are summarized as follows; Solids removal efficiency and moisture content of separated solid were 15~26% and 85~88%, respectively for the vibration separator. for the cylindrical separator, solid removal efficiency and moisture content of solid were 16~39% and 86~89%, respectively. The greatest amount of drymatter was obtained when operating vibration separator with 10$^{\circ}$ inclination and 100% vibrating power. For the cylindrical separator maximum efficiency was obtained with 40 rpm and 19$^{\circ}$ inclination. The vibration and the cylindrical separator have shown 21% and 26% in BOD removal, respectively. These two types of separator were proved to be applicable methods for animal wastewater separation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.305-309
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• 2005

This paper deals with an development of screen technology for marine waste disposal. The conception of inverse inclined screen is introduced. For optimal solid-liquid separation the vibration frequency, vibration angle and vibration method are inquired. And the efficiency of proposed technology and automatic apparatus is proved through the field test.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.1
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• pp.1-7
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• 2012

This study investigates free vibration characteristics of laminated composite structures with different embedded delamination sizes and locations using the solid element. The three-dimensional finite element (FE) delamination model described in this paper, in comparison with the conventional approaches, is more attractive not only because it shows better accuracy but also it shows the entire mode shape. The FE model using ABAQUS is used for studying free vibrations of laminates containing an various embedded delamination. The numerical results obtained are in good agreement with those reported by other investigators. In particular, new results reported in this paper are focused on the significant effects of the local vibration mode for various parameters, such as size of delamination, aspect ratio, and location of delamination.