• 한국농공학회지
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• 제19권2호
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• pp.4417-4422
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• 1977

This thesis is a result of theoretical and electrical experimental studies for the shape of Seepage on various Earth Dams. The decrement method of seepage through of water amount to earth Dam's was tested by means of experiment by the model constructed in the water tank. A study of the seepage through earth Dam's is necessary for a satisfactory of the same. An attempt was made in these investigations to study the problem of the seepage through homogeneous earth dams with filters located near the axis of the dam and filters extending in to upstream portion of the dam by the electrical analogy method. The experimental results were at variance with the graphical solution given by A Casagrande method. Some of the results were checked by relaxation method and by the circle criterion for drawing flow nets.

• 소성∙가공
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• 제17권8호
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• pp.607-612
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• 2008

The groove rolling is a process that transforms the bloom or billet into a shape with circular section through a series of rolling. Inhibition of surface defect generation in groove rolling is a matter of great importance and therefore many research groups proposed a lot of models to find the location of surface defect initiation. In this study, we propose a model for maximum shear stress ratio over equivalent strain to catch the location of surface defect onset. This model is coupled with element removing method and applied to box groove rolling of POSCO No.3 Rod Mill. Results show that proposed model in this study can find the location of surface defect initiation during groove rolling when finite element analysis results is compared with experiments. The proposed criterion has been applied successfully to design roll grooves which inhibit the generation of surface defect.

• 한국정밀공학회지
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• 제15권6호
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• pp.139-144
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• 1998

In Semi-Solid Forging, it is necessary to control the forming variables accurately in order to make near-net-shape products. Generally, the defects of products may occur due to liquid segregation which can be caused by the degree of deformation and strain rate, and condition of friction in Semi-Solid Forging, where the segregation is to be predicted by flow analysis. This paper presents the feasibility of theoretical analysis model using the new yield function for compressible P/M materials which is proposed by Doraivelu et at. to the flow analysis of the semi-solid dendritic Sn-15％Pb alloys instead of adopting the yield criterion of Shima and Oyane which is used by Charreyron and Flemings. The simple compression process is taken into consideration as the model to confirm the usefulness of the adopted yield function. The distribution of the liquid fraction at various strains and strain rates in radial direction, and the influence of friction are estimated by upper-bound method.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 가을 학술발표회 논문집
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• pp.16-23
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• 1997

The Reproducing Kernel Particle Method (RKPM), one of the popular meshless methods, is developed and applied to stress concentration problems. Since the meshless methods require only a set of particles (or nodes) and the description of boundaries in their formulation, the adaptivity can be implemented with much more ease than finite element method. In addition, due to its intrinsic property of multiresolution, the shape function of RKPM provides us a new criterion for adaptivity. Recently, this multiple scale Reproducing Kernel Particle Method and its adaptive procedure have been formulated for large deformation problems by the authors. They are also under development for damage materials and localization problems. In this paper the multiple scale RKPM for linear elasticity is presented and the adaptive procedure is applied to stress concentration problems. Therefore, this work may be regarded as the edition of linear elasticity in the complete framework of multiple scale RKPM and the associated adaptivity.

• 한국군사과학기술학회지
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• 제15권5호
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• pp.712-719
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• 2012

Penetrator with enhanced lateral effect(PELE) is a newconcept projectile, without dynamite and fuze. It consists of high-density jacket, closed at its rear end and filled with a low-density filling material. To study the explosion characteristics of PELE, by AUTODYN-3D code, the calculation models of projectile body and bullet target are established and the process of penetrating aluminum-2024 alloy target of PELE is simulated, and the scattering characteristics after penetrating aluminum-2024 alloy target of PELE are studied by different initial velocity. The explicit finite element analysis of PELE fragmentation was implemented with stochastic failure criterion in AUTODYN-3D code. As expansion of filling, the fragments were obtained velocities and dispersed laterally and further more enhancing the damage area largely. The number and shape of the PELE fragments were different depend on impact velocity and incidence angle of filling which fragment generated during penetration and lateral dispersion process.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1055-1057
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• 2004

This paper deals with a qualitative analysis of iron loss in Transverse Flux Linear Motor (TFLM). 3D equivalent magnetic circuit network method (EMCNM) is used as an analytical method to get flux density of each element. The total core loss is calculated with the magnetic flux density and core loss curves of an optional material. The results of iron loss analysis can be used as a criterion to decide the manufactural shape such as lamination or solid type core, skew position, etc.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2001년도 학술논문발표회
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• pp.1-7
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• 2001

To do performance evaluations about inorganic permanent form mixed in admixture(fly ash, silica fume) and after placed concrete, it is examined reinforcement materials in the permanent form from shear strength, bond strength and flexural strength tests. In this study, permanent form was inserted with reinforcement metal fitting is strength-tested in several method. The result of this study is belows. (1) In bond strength test, Most specimens are satisfied with criterion-6 kgf/$cm^2$. (2) Irrelative with the inserted metal fitting's shape, unevenness and aggregate, Permanent form and after placed concrete have good condition in the shear strength test. (3) In flexural test, there is no drop out of permanent form. Most cracks are located in nearby the strain point.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.665-670
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• 2001

The purpose of this paper is to verify a finite element model of an automotive exhaust system using Modal testing. In general, a lot of finite element models are used in initial design step of automotive development. One of them is a finite element model of an exhaust system. Verification on the finite element model of an automotive exhaust system is indispensable. In this paper, a finite element analysis on the exhaust system using MSC/NASTRAN is carried out, and the results are compared with those obtained by modal testing. By comparing MAC values of the analytical modes with the experimental modes, the finite element model of the automotive exhaust system is verified.

• 설비공학논문집
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• 제11권5호
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• pp.700-708
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• 1999

The optimum dimple shape and arrangement in the channel of a plate heat exchanger with staggered dimples are proposed in this study. Four important geometric parameters are selected as design variables, the pressure drop and heat transfer characteristics are examined in the channel of plate heat exchangers. The optimization is accomplished by minimizing the global criterion function which consists of the correlations of Nusselt number and pressure drop. The optimum geometric parameters were found at the dimensionless dimple distance (L) of 0.272, the dimensionless dimple angle ($\beta$) of 0.44, the dimensionless dimple volume (V) of 0.106 and the dimensionless dimple pitch (G) of 0.195. It is found that the heat transfer and pressure drop of the optimum model are increased by approximately 227.9% and 32.9%, respectively, compared to those of the base model.

• 한국수자원학회논문집
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• 제40권5호
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• pp.373-382
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• 2007

수로가 시작되는 지점의 정확한 위치를 찾는 것은 구릉지 사면상의 물의 동적거동으로 인하여 매우 어렵다. 이러한 목적을 위하여, 김주철과 김재한(2007)은 DEM을 이용한 경사와 면적 사이의 규모에 따른 거동특성에 따라 실제 유역내 수로망을 제시한 바 있다. 본 연구는 이들의 연구 성과의 연장으로서, 배수밀도와 수원유역의 기하학적 특성을 기반으로 하여 DEM으로부터 동정된 가설수로망의 신뢰성을 평가하여 보았다. 그 결과 경사-면적한계기준에 의한 가설수로망이 자연유역의 배수구조를 매우 잘 묘사하고 있음을 확인할 수 있었다. 또한 지형학적 동질성을 가진 지역내 수원유역의 형상들 사이에는 훌륭한 기하학적 상사성이 존재함을 추론할 수 있었다. 면적한계기준은 수원유역의 형상을 구속하여 왜곡된 배수구조를 야기할 수도 있었다. 그럼에도 불구하고 DEM으로부터 동정된 가설수로망들이 공간 채움 구조를 잘 표현하고 있는 점이 특히 주목된다.