• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.169-176
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• 2005

Many RC building structures of multiple uses constructed in Korea have the irregularities of torsion and soft story at bottom stories. A typical irregular building was selected as prototype and shaking table tests were performed to investigate the seismic performance of this building. The objective of this study is to evaluate the correlation between the experimental and analytical responses of this irregular building structure subjected to the earthquake excitation by using OpenSees(Open System for Earthquake Engineering Simulation). The results of analyses simulate well the effect of axial forces on the shear force of column and axial deformation. However, some discrepancy between analytical and experimental results in the distribution of shear forces and overturning deformation were observed.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.154-158
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• 2000

Hydraultic experiments were performed in 2-D were flume to investigate the stability o the breakwaters, the destruction of armor blocks and overtopping under irregular wave attack on the structures armored by \`Core-Loc\`. Overtopping rate and stability were examined and compared when armored by Core-Loc and by T.T.P. Results shows both type of blocks are stable and overtopping rates are similar in the adopted experimental condition. Therefore Core-Loc can replace some portion of T.T.P. which is uniquely used in Korea. Further integrated experimental data with Core-loc are need for destruction mechanism or overtopping rate.

• Journal of Industrial Technology
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• v.15
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• pp.71-75
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• 1995

A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross-sections and with arbitrary boundary conditions was developed and reported by D. H. Kim in 1974. This method has been developed for two-dimensional problems including the laminated composite plates and was proved to be very effective for the plates with arbitrary boundary conditions and irregular sections. In this paper, the result of application of this method to the clamped composite plates with non-uniform cross-section and with attached point mass/masses is presented.

• Journal of Industrial Technology
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• v.15
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• pp.169-174
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• 1995

A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross-sections and with arbitrary boundary conditions was developed and reported by D. H. Kim in 1974. IN this paper, the result of application of this method to the laminated plates with axial forces and with attached point mass/masses is presented. Both $N_x$ and $N_y$ forces are considered. The solution for the laminated plates with arbitrary boundary conditions and irregular section can be obtained by simply obtaining the deflection influence coefficients by any method. The effect of neglecting the mass of the plates on the natural frequency, as the ratio of the point mass/masses to the plate mass increases, is thoroughly studied. The influence of $N_x$ and $N_y$ is also carefully investigated.

• Applied Microscopy
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• v.19 no.2
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• pp.17-26
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• 1989

The cells of Campylobacter jejuni treated with physical or chemical disinfection agents were comparatively examined by scanning and transmission electron microscopies for their morphological features and internal ultrastructures. The normal cells of C. jejuni, showed typical spiral rod shapes. The ribosomes, nucleoids, and other cellular constituents were observed to be distributed evenly throughout the cytoplasm. The cells treated with heat or UV-light were changed to spherical or irregular shapes and their cell envelopes were destroyed to form ghost cells by liberating their cytoplasmic components. The cells treated with chlorine or monochloramine were also changed into irregular round shapes. The chlorinated cells showed very rough surface structures with many blob-like protrusions, while the surface of the monochloramine-treated cells appeared to be relatively smooth.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.215-222
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• 1997

A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross-sections and with arbitrary boundary conditions was developed and reported by D. H. Kim in 1974. This method has been developed for two-dimensional problems including the laminated composite plates and was proved to be very effective for the plates with arbitrary boundary conditions and irregular sections. In this paper, the result of application of this method to the subject problem is presented. This problem represents the building slabs with a kind of passive and active control devices. Any method may be used to obtain the deflection influence surfaces needed for this vibration analysis. Finite difference method is used for this purpose, in this paper. The influence of the modulus of the foundation on the natural frequency is thoroughly studied.

• Computational Structural Engineering
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• v.11 no.4
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• pp.287-294
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• 1998

입면의 형태가 임의의 층에서 큰 차이를 보이는 3차원 비정형 setback 구조물의 동적 거동 특성과 이들 구조물의 동적 거동에 미치는 바닥 슬래브의 면내 변형 효과를 분석하였다. 비정형 setback 구조물의 전반적인 동적 거동특성을 분석하기 위하여 베이스 부분의 평면적과 타워 부분의 평면적 비(R?), setback 발생위치(L?)등을 매개 변수로 사용하였다. 48개의 비정형 setback 구조물들에 대한 해석 수행 결과 setback 구조물은 정형 구조물에 비해 횡방향 1차 모드의 유효 모드 중량(effective modal weight)이 작게 나타나는 경향을 보이기 때문에 setback 구조물의 동적 거동을 파악하기 위해서는 등가 정적 해석법 대신에 동적 해석을 수행할 필요가 있음을 알 수 있었다. 바닥슬래브의 면내 변형은 보다 긴 구조물의 고유 진동 주기값을 가져오며 모드 순서 및 모드 형상에도 변화를 준다. 이러한 사실은 바닥슬래브의 면내 변형으로 인하여 횡방향 저항 요소들간의 전단력 분포와 층 변위가 영향을 받을 수 있다는 것을 의미한다. 이러한 현상은 횡방향 저항 요소들간의 강성 차가 심한 프레임-전단벽 시스템에서 두드러지게 나타난다.

• Structural Engineering and Mechanics
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• v.11 no.4
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• pp.443-460
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• 2001

This paper presents an effective application of a variable-node axisymmetric solid element designated as AQV (Axisymmetric Quadrilateral Variable-node element). The variable-node element with physical midside nodes helps to overcome some problems in connecting the different layer patterns on a quadrilateral mesh in the adaptive h-refinement. This element alleviates the necessity of imposing displacement constraints on irregular (hanging) nodes in order to enforce the inter-element compatibility. Therefore, the elements with variable mid-side nodes can be used effectively in the local mesh refinement for the axisymmetric structures which have stress concentrations. A modified Gaussian quadrature should be adopted to evaluate the stiffness matrices of the variable-node elements mainly because of the slope discontinuity of assumed displacement within the elements. Some numerical examples show the usefulness of variable-node axisymmetric elements in the practical application.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.225-232
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• 2006

Three building structures haying piloti frames in the lower two stories were selected as prototypes and were analyzed using nonlinear static analysis to investigate the seismic capacity of these buildings. The first one has a symmetrical moment resisting frame (Model 1), the second has an infilled shear wall in the central frame (Model 2), and the third has an infilled shear wall only in one of exterior frames (Model 3), The analytical results were compared with those of shaking table tests with regards to the overstrength and ductility of the irregular buildings. Infilled shear wall in Model 2 and Model 3 induced large overstrength factors, 6.8 and 6.0, respectively, which are about two times larger than that of Model 1, 3.5. The displacement ductility ratio in Model 2 was only 2.5, due to the shear failure of wall in the piloti stories, whereas those of Model 1 and Model 3 reached 3.2.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.210-213
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• 2010

Recent experimental data shows that the noticeable feature of irregular roughened spots on the fuel surface occurs during the combustion test. The generation of these unexpected patterns is likely to be resulted from the disturbed boundary layer due caused by wall blowing which is intended to simulate the process of fuel vaporization. LES without chemical reaction was conducted to investigate the flow characteristics at the near-fuel surface and the behavior of turbulent structures which is evolved by the wall blowing at the Reynolds number of 23,000. Cylindrical geometry was considered to get the most reality of the calculation results because real hybrid rocket motor is circular grain configuration. It was shown that the wall blowing pushed turbulent structures upwards making them tilted and this skewed displacement, in effect, left the foot prints of the structures on the surface. This change of kinematics may explain the formation of irregular isolated spots on the fuel surface observed in the experiment.