• Geomechanics and Engineering
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• 제10권4호
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• pp.405-422
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• 2016

The paper deals with the results of the laboratory cyclic plate load tests performed on the reinforced soft clay beds. The performances of the clay bed reinforced with geocells and geocells with additional basal geogrid cases are compared with the performance of the unreinforced clay beds. From the cyclic plate load test results, the coefficient of elastic uniform compression ($C_u$) was calculated for the different cases. The $C_u$ value was found to increase in the presence of geocell reinforcement. The maximum increase in the $C_u$ value was observed in the case of the clay bed reinforced with the combination of geocell and geogrid. In addition, 3 times increase in the strain modulus, 10 times increase in the bearing capacity, 8 times increase in the stiffness and 90% reduction in the settlement was observed in the presence of the geocell and geogrid. Based on the laboratory test results, a hypothetical case of a prototype foundation subjected to cyclic load was analyzed. The results revealed that the natural frequency of the foundation-soil system increases by 4 times and the amplitude of the vibration reduces by 92% in the presence of the geocells and the geogrids.

• Geomechanics and Engineering
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• 제14권2호
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• pp.115-129
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• 2018

This paper presents a set of results of plate load tests that imposed incremental cyclic loading to a sandy soil bed containing multiple layers of granulated rubber-soil mixture (RSM) at large model scale. Loading and unloading cycles were applied with amplitudes incrementally increasing from 140 to 700 kPa in five steps. A thickness of the RSM layer of approximately 0.4 times the footing diameter was found to deliver the minimum total and residual settlements, irrespective of the level of applied cyclic load. Both the total and residual settlements decrease with increase in the number of RSM layers, regardless of the level of applied cyclic load, but the rate of reduction in both settlements reduces with increase in the number of RSM layers. When the thickness of the RSM layer is smaller, or larger, settlements increase and, at large thicknesses may even exceed those of untreated soil. Layers of the RSM reduced the vertical stress transferred through the foundation depth by distributing the load over a wider area. With the inclusion of RSM layers, the coefficient of elastic uniform compression decreases by a factor of around 3-4. A softer response was obtained when more RSM layers were included beneath the footing damping capacity improves appreciably when the sand bed incorporates RSM layers. Numerical modeling using "FLAC-3D" confirms that multiple RSM layers will improve the performance of a foundation under heavy loading.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.408-413
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• 1997

The linear dynamic response of a simply supported uniform beam under a moving load of constant magnitude is investigated. When the ratio of the moving weight and the structure weight is small, moving object is considered as a concentrated or distributed moving force, that is large external loading can be considered as a concentrated or distributed moving masses. Result from the numerical solutions of the differential equations of motion are shown graphically. Moreover, when considering the maximum deflection for the mid-span of the hewn, the critical speeds of the moving load have been evaluated.

• 한국정보처리학회논문지
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• 제4권6호
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• pp.1615-1624
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• 1997

본 논문에서는 미러링을 이용한 디스크 시스템의 복구기법을 제안하고 분석한다. 디스크 결함발생시 수행되어 지는 복구과정이 사용자 디스크 요구에 대한 평균 응답시간에 미치는 영향을 다룬다. 또한, 복구과정 및 성능에 미치는 응용의 입출력 패턴들의 효과를 분석한다. 실험 결과에 따르면 시스템의 부하가 커질수록 일양접근 패턴에 비해 비일양접근 패턴에 대한 평균 응답시간이 짧아진다. 시뮬레이션 결과는 짧은 지연을 가지는 제안된 복구기법이 기존의 기법보다 더 좋은 성능을 가짐을 보인다.

• Progress in Superconductivity
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• 제5권2호
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• pp.144-148
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• 2004

Uniform current distribution among conductor layers in HTS cables using IPTs (inter-phase transformers) was investigated. Conventional methods for current distribution, in which resistors are inserted to conductor layers, causes additional loss. In contrast, IPTs, which use magnetic coupling, make it possible that the current in parallel circuits is distributed uniformly with any load, and minimize the loss. In this study, IPTs were designed and fabricated for examination of uniform current distribution in the conductor layers of HTS cables. The ITP was designed through calculation of its impedance that can cancel the inductance of the conduction layers. The experimental setup consisted of four IPTs and four inductors that simulate the conductor layer inductance. Each layer was designed to feed 10 A. We examined the behavior of current distribution with IPTs for various layer inductances.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.20-27
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• 2005

Solar radiation causes non-uniform temperature distribution in the structure, depending on the shape of the structure and its shadows. Especially in cases of curved steel box girder bridges, non-uniform temperature distribution due to solar radiation can reduce bridge life and serviceability when combined with another load combination. In this study, the method for predicting the temperature distribution of curved bridges developed by Kim et al., was used to predict the non-uniform temperature distribution which served as a basis for structural analysis of 3-D bridge behavior. In order to seek the most unfavorable conditions of solar radiation, observation data from the Korea Meteorological Administration for solar radiation were analyzed. The region of the most high solar radiation condition was selected and its one year variation of the solar radiation data was considered. From this analysis, the most unfavorable solar radiation condition with lower solar altitude and intense solar radiation was selected. Based on the selected solar radiation condition, structural behavior of curved bridges with diverse bridge direction, span length, radius and support conditions are analyzed.

• Structural Engineering and Mechanics
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• 제21권5호
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• pp.519-537
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• 2005

A new generalized Bernoulli/Timoshenko beam-column element on a two-parameter elastic foundation is presented herein. This element is based on the exact solution of the differential equation which describes the deflection of the axially loaded beam resting on a two-parameter elastic foundation, and can take into account shear deformations, semi - rigid connections, and rigid offsets. The equations of equilibrium are formulated for the deformed configuration, so as to account for axial force effects. Apart from the stiffness matrix, load vectors for uniform load and non-uniform temperature variation are also formulated. The efficiency and usefulness of the new element in reinforced concrete or steel structures analysis is demonstrated by two examples.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.17-22
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• 2002

Non-uniform and unsteady inflow into a Horizontal Axis Wind Turbine (HAWT) brings about an asymmetric flow field on the rotor plane and an unsteady aerodynamic load on the blades. In the present paper effects of yawed inflow and wind shear are analyzed by an inviscid aerodynamic model based on the asymptotic acceleration potential method. In the analysis the rotor blades are represented by spanwise and chordwise pressure distribution composed of analytical first-order asymptotic solutions for the Laplace equation. As the actual wind field experienced by a HAWT is turbulent, the effects of the turbulence are also examined using the Veers' model.

• 한국공간정보시스템학회:학술대회논문집
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• 한국공간정보시스템학회 2004년도 춘계 학술발표회 논문집 제1권1호(통권1호)
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• pp.83-88
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• 2004

First author proposed a proportioning method for member sections of a single layer reticulated dome subjected to uniform and non-uniform load without any geometrical initial imperfection, and discussed the validity and effectiveness of the method which was based on linear buckling stress and a knock down factor. However, buckling of a single layer reticulated dome is strongly affected by initial imperfection. It is well known that geometrical initial imperfections reduce the nonlinear buckling capacity of a single layer raticulated dome. Thus, structural engineers may be recommended to reflect the effects of geometrical initial imperfections in proportioning member sections. In this paper, firstly, the presented proportioning method by first author is applied to dome without consideration of any imperfections and the thickness and diameter of each member are determined. Secondly, the load bearing capacities of the proportioned domes are checked with the imperfection, by the inelastic buckling analysis.

• Advances in Computational Design
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• 제5권4호
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• pp.349-362
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• 2020

Dynamic characteristics of a scale-dependent porous metal foam cylindrical shell under a traveling load have been explored within this article based on a numerical approach. Within the material texture of the metal foams, uniform and non-uniform porosities may be dispersed. Based upon differential quadrature method (DQM) and Laplace transforms, the equations of motion for a shear deformable scale-dependent shell may be solved numerically. Scale-dependent shell modeling has been provided based upon strain gradient elasticity. Solving the equations will give the shell deflection as a function of load speed. Also, it is reported that shell deflection relies on the porosity dispersion and strain gradient influences.