• Composites Research
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• v.24 no.3
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• pp.6-11
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• 2011

This paper presents an estimating method for local property changes and failure prediction of composite materials experiencing large shear deformation during draping process. The bone plate for the metaphyseal femur fracture was chosen to apply the presented method because it has complex geometry. The local property changes due to macro-/microscopic deformations of fabric composites during draping process were evaluated by various tests and the result was applied to predict static/fatigue behaviors of the bone plate. This paper was expected to present useful information on the design of composite structures with complex geometry and their performance evaluation.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.1
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• pp.39-58
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• 2004

It is very important that predict the inelastic seismic behavior exactly for seismic performance evaluation of a building in the performance based seismic design. Evaluation method of seismic performance based on the pushover analysis reflected in PBSE was developed by some researchers. For the evaluation of inelastic global and local seismic responses by pushover analysis exactly. lateral load distribution should be adjusted and reflected the dynamic characteristics of structural system and various seismic ground motions. And performance point should be determined based on the evaluation of reasonable deformation capacity of a building more exactly. An effective method based on the improved the adaptive lateral load distribution and the equivalent responses of a multistory building is proposed in this study to efficiently estimate the accurate inelastic seismic responses. The proposed method can be used to evaluate the seismic performance for the global inelastic behavior of a building and to accurately estimate its local inelastic seismic responses. In order to demonstrate the accuracy and validity of this method, inelastic seismic responses estimated by the proposed method are compared with those obtained from other analytical methods.

• Journal of Korean Society of Steel Construction
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• v.10 no.2 s.35
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• pp.187-199
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• 1998

The highspeed railway bridge which support continuous and high moving mass evalute the dynamic state and make the displacement of the bridge makes more or less, but up to this time the bridges are designed by the static design concept. for example when we design bridge we use impact factor, which only times the static load makes dynamic load. But becouse it simples. it can't express all of the effects. And so, in this report we study the modeling method of the moving mass and the dynamic factor.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.2
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• pp.121-131
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• 1986

The stiffness matrix of circularly curved frame elements including the warping effects is formulated by the solutions of vlasov's differential equations, and the procedure for the elastic static analysis of curved girder systems by the displacement method is presented. The validity of this method has been demonstrated by comparing the analysis results with other solutions. And if the tangential lines of the two frame element axes connected at any nodal point coincide, the transformation to the global coordinate system can be omitted when we analyze the structures consisting of circularly curved elements. The theory introduced in this thesis can be applied with sufficient accuracy to the structures built up with horizontally circular curved frame elements which have closed or open cross sections and are symmetric to the axis perpendicular to the plane of the curvature, such as prestressed concrete box girder bridges.

• Journal of the Korea Society for Simulation
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• v.24 no.3
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• pp.69-75
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• 2015

This research focuses on structural stability of the multi-aerial platform. In this study, we conduct structural analysis for the lower structures such as sub frame, out-trigger and chassis frame, by using a universal structural analysis program NASTRAN based on 3D CAD data, material properties, load conditions and boundary conditions. We confirm the position of local stress exceeding the yield strength, through structural analysis of 4 cases for load conditions. As the results, it is possible to relax stress concentration in a way such as changing the thickness, reinforcing the material of the lower frames.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.1
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• pp.33-41
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• 2002

Recently, the seismic safety evaluation of concrete gravity dams is raised due to the damage or the failure of dams occurred by the 1995 Kobe earthquake, the 1999 Taiwan earthquake, etc. Failre of dam may incur loss of life and properties around the dam as well as damage to dam structure itself. Recently, there has been growing much concerns about 'earthquake-resistance' or 'seismic safety'of existing concrete gravity dams designed before current seismic design provisions were implemented. This research develops three evaluation levels for seismic safety of concrete gravity dams on the basis of the evaluation method of seismic safety of concrete gravity dams in U.S.A., Japan, Canada, and etc. level 1 is a preliminary evaluation which is for purpose f screening. Level 2 is a pseudo-static evaluation on the basis of the seismic intensity method. Finally, level 3 is a detail evaluation by the dynamic analysis. Evaluation results on existing concrete gravity dam on operation showed good seismic performance under the designed artificial earthquake.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.840-844
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• 2005

최근 기상이변에 따라 특정지역에 단시간의 집중호우에 의한 홍수가 빈번히 발생하고 있으면, 이에 따른 위험과 손실이 증가하고 있다. 집중호우 발생시 단지설계 및 배수체계 부분에 관련하여 도출되는 가장 중요한 문제점 중의 하나는 배수시스템의 배수불량으로 인한 단지 내수침수문제라 할 수 있다. 기존 지역 배수시스템의 설계빈도는 20년을 넘지 못하고 있는 실정이나 집중호우는 이를 상회하므로 국부적인 단지내 배수시스템 불량은 피할 수 없는 현상이다. 하지만 기존의 배수시스템 설계기법은 합리식을 기본으로 하는 정적개념의 설계 기법이므로 국부적인 배수시스템의 손실수두 발생에 의한 국지적 침수 양상을 파악하기는 부적절하다. 본 논문에서는 과거 집중호우로 인해 피해가 발생했던 중랑천 유역 중 침수가 자주 발생했던 중랑구를 대상유역으로 결정하였다. SWMM, ILLUDAS 모형을 이용하여 대상유역에 대한 유출 해석을 실시한 결과 도시유역에서는 SWMM 모형이 그 적용성에 있어서 다소 효과적인 것으로 나타났다. 도시유출모형을 GIS와 연계하기 위하여 지형공간데이터를 구축하고 GIS 도구인 Arc/Info와 ArcView를 이용하여 연계하는 방안을 제시하였으며, 유출모형의 결과값을 이용하여 침수구역도를 작성하였다. GIS와 연계시 실제 침수가 예상되는 범위을 가시화함으로써 침수발생지점을 사전에 예측할 수 있고 침수예방을 위한 기초자료로 활용할 수 있을 것으로 판단된다.

• Geophysics and Geophysical Exploration
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• v.1 no.1
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• pp.71-78
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• 1998

Inversion schemes of 2-D MT survey data generally take enormous computational time and computer memory. In addition, careful attention must be paid in handling MT data, especially in cases of TM mode, inversion results can be seriously distorted because of static effect caused by current channeling across inhomogeneous surface boundaries. There-fore inversion algorithm using the GRRI scheme for TM mode MT data was implemented. This scheme is based on a perturbation analysis with a locally 2-D analysis and local inversions were sequently performed over each divided section without additional forward modelings. The algorithm was applied to several synthetic data for the purpose of verification of its efficiency and applicability. With less computer resources than conventional schemes, it could handle static effect directly by including current channeling across inhomogeneous boundaries. Thus it is expected to be used for an useful tool such as a real-time inversion scheme in the field.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.2
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• pp.105-114
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• 2018

In this paper, the computer simulations are carried out by using the peridynamic theory model with various conditions including quasi-static loads, dynamic loads and crack propagation, branching crack pattern and isotropic materials, orthotropic materials. Three examples, a plate with a hole under quasi-static loading, a plate with a pre-existing crack under dynamic loading and a lamina with a pre-existing crack under quasi-static loading are analyzed by computational simulations. In order to simulate the quasi-static load, an adaptive dynamic relaxation technique is used. In the orthotropic material analysis, a homogenization method is used considering the strain energy density ratio between the classical continuum mechanics and the peridynamic. As a result, crack propagation and branching cracks are observed successfully and the direction and initiation of the crack are also captured within the peridynamic modeling. In case of applying peridynamic used homogenization method to a relatively complicated orthotropic material, it is also verified by comparing with experimental results.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1992.11a
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• pp.50-56
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• 1992

공업재료의 표면은 수많은 돌기들로 구성되어 있으며 이러한 돌기들의 접촉으로 진실접촉이 이루어진다. 그러므로 마찰은 겉보기 접촉면적과는 무관하며 진실접촉면에서 일어난다. 표면의 한 돌기가 접촉면과 상대운동을 함으로 인하여 마찰열이 발생된다. 이러한 마찰에너지 발산의 결과로서 진실접촉면적 주위의 국부적인 표면 온도가 상승되며 따라서 표면의 평균온도가 상승된다. 이러한 표면온도를 결정하기 위한 이론적 및 실험적인 방법이 많이 제시되어왔다. 정적상태에서의 표면온도는 Block(1937)과 Jaeger(1942)에 의해 이론적으로 소개하였다. Jaeger는 열원의 위치와 상대적인 접촉운동 그리고 크기 및 경계조건 등의 특정한 조건 하에서 진실접촉점의 온도를 계산하였다. 이에 Bany와 Baber(1984)는 그들의 경계조건이 잘목 정의되었음을 지적하고 더욱 세분화된 경계조건으로 온도분포를 유도한 바 있다. Ling(1969)은 접촉점에서의 온도가 주변의 겉보기 접촉면적의 온도보다 훨씬 높다는 것을 수치해석으로 밝혀냈다. 본 연구는 고속정밀촬영기를 이용하여 진실접촉점에서 발생하는 Hot spot의 온도분포를 실험을 통하여 규명하고 그 결과를 Geoim과 Winer의 이론식에 적용하므로 식의 유용성을 검증하는데 그 목적이 있다.