• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1990년도 가을 학술발표회 논문집
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• pp.63-67
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• 1990

The purpose of this study was to investigate the effects of flexural strength ratio(Mr=$\Sigma$Mc/$\Sigma$Mb) with High-Strength Concrete up to 800Kg/$\textrm{cm}^2$. Five specimens were tested under reversed cyclic loadings. The primary variables were flexural strength ratio of the beam-column, compressive strength of concrete and loading patterns. The results showed that the failure at the beam-column joint in case of high strength concrete was severe more than in case of normal strength concrete when flexural strength ratio 1.4. Thus the part for low limit of flexural strength ratio(Mr=1.4) should be revised for high strengthconcrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1991년도 가을 학술발표회 논문집
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• pp.93-98
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• 1991

Polymer-Impregnated Concrete(PIC) can be considered composite material of concrete and polymer and has superior properties compared to conventional cement concrete, such as strength, stiffness, toughness, durability, water-proofing, chemical resistance. However, so far, the usage of PIC has been limited to repairing materials and non-structural applications, due to the lack of the design criteria and the analytical model to determine structural behavior. The objective of this study is to define the stress-strain response and strength characteristics of PIC in uniaxial and various biaxial compressive loading. On the bases of experimental results, general stress-strain relation, biaxial failure envelope and strength evaluation formular of PIC made with normal aggregate and methylmethacrylate(MMA) are proposed.

• 연구논문집
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• 통권22호
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• pp.65-74
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• 1992

This paper aims at calculating optimum design dimensions to minimize the weight satisfied strain and stress intensity of the frame while loading maximum weight into a mechanical press in the static condition. Analysis of the frame was carried out by using the FEM, then the optimum condition was obtained by using these data. As modeling in the finite element analysis has great impact on the reliablity of analysis results, the analyzed object was selected a 150-ton mechanical press of J Company, the part little affected to structural rigidity was simplified, the load condition was considered in the only maximum load, the boundary condition was used by giving symmetric displacement due to symmetric boundary condition, the finite element was applied a linear membrane element. An intermediate processor program applied the normal ANSYS to analyze finite elements was developed, and the design sensitivity was calculated. This program was applied to the optimum design.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.225-228
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• 2005

The purpose of this study is to investigate effects of the plastic/elastic deformation energy on wet etching characterization on the surface of material by using the nanoindentation and HF wet etching technique. Indents were made on the surface of Pyrex 7740 glass by the hyperfine indentation process with a Berkovich diamond indenter, and they were etched in $50\;wt\%$ HF solution. After etching process, convex structure was obtained due to the deformation-induced hillock phenomena. In this study, effects of indentation process parameters (normal load, loading rate) on the morphologies of the indented surfaces after isotopic etching were investigated from an angle of deformation energies.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.301-306
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• 2000

Small passenger and car carrier ships are mainly used as a connection way between land and small islands. And these ships should be designed to enlarge the capacity of passenger and car loading within limited space and draft. So the resonances of various vibrations exist in normal operation range of engine and propulsion shafting. In this paper, hull's superstructure vibration which was especially induced by the 1st order excitation of whirling vibration on the 2-engines and 2-propulsion shafting systems is introduced. Also these are verified via the theoretical analysis using transfer matrix method and FEA software ANSYS and its vibration measurement.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.42-44
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• 2004

This paper introduced and proposed the voltage unbalance of DC terminal output as new monitoring parameter for power islanding detection. This paper also presented a simple and novel detection algorithm, which effectively combines the detection results of the conventional parameter, voltage magnitude, and a newly proposed parameter. We tested the proposed method using several distribution network conditions including not only islanding operation conditions, but also non-islanding conditions of normal network load variations. The test results showed that the proposed parameters and algorithm are capable of correctly detecting the islanding operation not affected by variation of DG loading and also have a good selectivity for islanding conditions and non-islanding conditions.

• 한국철도학회논문집
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• 제7권1호
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• pp.49-54
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• 2004

Particularly derailing freight wagon, which are loaded with dangerous chemicals, has large damages on humans and environment. In this paper the dynamic characteristic of the laminated leaf spring under extreme situation, for example derailment, is examined. The leaf spring has a static hysteresis. Not only the friction value, but also the spring rate are influenced by this hysteresis characteristic. Because of the static hysteresis of the leaf spring the spring rate must be used in normal operation depending upon the loading and the kind of the excitation with the up to 10-fold value of the static spring rate. Some characteristics of the leaf spring can be treated like well-known viscous damping, but fer special situation (preload and/or excitation) particular calculation are necessary.

• Wind and Structures
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• 제27권6호
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• pp.439-449
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• 2018

Wind loading of a tall building built amidst a group of buildings in urban environment is always greatly affected by shielding effects. Wind tunnel tests were carried out to assess the shielding provided by a row of low-rise or medium-rise buildings upstream a square-section tall building of height-to-breadth ratio 6. Mean and dynamic wind loads on the tall building were measured at different wind incidence angles and presented as interference factors (IFs). It is found that presence of a row of upstream buildings provides significant shielding to the tall building. At normal wind incidence, the mean along-wind loads and all components of fluctuating wind loads on the tall building are always reduced by shielding. Vortex shedding seems to still occur on the upper exposed part of the tall building but the vortex excitation levels are largely reduced. The degree of shielding is found to depend on a number of arrangement parameters of the row of upstream buildings. Empirical equations are proposed to quantify the shielding effect based on the wind tunnel data.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.325-342
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• 2020

The current study is focused on the evaluation of the ultimate strength of stiffened panels found in ship hull structures that are subjected to combined uniaxial thrust, in-plane and out-of-plane bending moments. This loading condition, which is in general ignored when performing buckling checks, applies to representative control geometries (stiffener with attached plating) as a consequence of the linearly varying normal stresses along the ship's depth induced by the hull-girder vertical bending moment. The problem is generalized by introducing a non-uniform thrust described by a displacement ratio and rotation angle and by introducing the slenderness ratios, within the practical range of interest. The formed design space is explored through methods sourcing from Design of Experiments and by applying non-linear finite element procedures. Surrogate empirical models have been constructed through regression analysis and Response Surface Methods. An additional empirical model is provided to the literature for predicting the ultimate strength under uniaxial thrust. The numerical experimentation has shown that is a significant influence on the ultimate strength of stiffened panels as the thrust non-uniformity increases.

• 생물정신의학
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• 제15권2호
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• pp.83-91
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• 2008

목 적 연성 신경학적 징후는 정신분열병의 유전과 관계되는 생물학적 표현형으로 여겨져 왔다. 본 연구에서는 연성 신경학적 징후가 유전적 하중과 관련해서 가족 내에서 연관성을 보이는지를 알아보고자 하였다. 대상 및 방법 정신분열병 환자로서 부모 중 한 명은 정신분열병의 가족력이 있고 나머지 한 명은 가족력이 없는 환자가(N=14) 모집되었다. 이들의 부모가 가진 가족력에 따라 유전적 하중을 정하였고 이를 위해 Family Interview for Genetic Studies(FIGS)로 직접 면담을 시행하였다. 환자의 부모에서 환자를 제외한 1차 혹은 2차 친척에서 정신분열병 환자가 있는 부모를 유전적 하중이 있는 '추정 보유자'(presumed carrier)(N=9)로, 그렇지 않은 부모를 '추정 비보유자' (presumed noncarrier)(N=11)로 구분하였다. 또한 정상 대조군은 1차 혹은 2차 친척에서 정신분열병의 가족력이 없는 일반인(N=12)이었다. 이들의 연성 신경학적 징후를 한국어판 신경학적 평가 척도(Neurological Evaluation Scale-Korean version)를 사용하여 평가하였으며 가족내 연관성에 대한 분석 방법으로 급내 상관계수법(Intra-Class Coefficients[ICC]) method)을 이용하였다. 결 과 연성 신경학적 징후의 하위 영역 중 운동 조정 영역에서 환자와 추정 보유자 간에 유의한 연관성이 존재하였고(ICC=.804, p=.016) 환자와 추정 비보유자와는 연관성이 존재하지 않았다. 운동 조정 영역 이외의 다른 하위 영역에서는 유전적 하중과 상관없이 가족내 연관성이 존재하지 않았다. 그러나, 환자군과 정상 대조군의 운동 조정 영역의 점수 간에는 통계적으로 유의한 차이가 존재하지 않았다. 결 론 이번 연구에서는 연성 신경학적 징후들이 정신분열병의 유전적 하중과 같이 유전되는 생물학적 표현형일 가능성이 입증되지 못하였다. 향후 보다 많은 수를 대상으로 한 추시 연구가 필요하다.