• Title/Summary/Keyword: Discrete element method

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Layout Principles of Renaissance Classicism Architectural Style and Its Application on Modern Fashion Design - Focused on Classic Style Fashion after the Year 1999 - (르네상스 고전주의 건축양식의 조형원리와 현대패션디자인에의 적용 - 1999년 이후 클래식 스타일 패션을 중심으로 -)

  • Lee, Shin-Young
    • The Research Journal of the Costume Culture
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    • v.18 no.2
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    • pp.261-276
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    • 2010
  • The analysis of an art trend in the principle dimension starts by observing the object of work in the perspective of formative composition and recognizing it as a universal system. It can be said that it is consistent with an interpretation method for a form theory of formal history by Heinrich W$\ddot{o}$lfflin, a leading form critic in art criticism. Hence, the purpose of this study was to find out what are the formative principles in Renaissance Classicism as a design principle to be applicable to modern fashion by reviewing the formative characteristics of Renaissance Classicism Architecture with which W$\ddot{o}$lfflin directly dealt. As for the theoretical literature review, I used W$\ddot{o}$lfflin's theoretical framework and looked at the Renaissance Classicism Architecture that he studied and examined the possibility of utilizing his theory as a layout principle and the characteristics. As for analysis of design cases, I applied the aforementioned architecture layout principle to modern fashion and conducted case study analysis to delve into distinctive layout principles found in fashion. The study showed that the Renaissance Classicism Architectural Style is marked by linearity, planarity, closing and multiple unity: linearity was expressed in the observation form in fixed frontal view and an emphasis on a tangible silhouette homeogenous and definite line structures; planarity was achieved in the form of paralleled layers of frontal view element, planarity style, and identical and proportional repetition of various sizes.; closing signified the pursuit of complete and clear regularity, and architecture developed in a constructive phase through organizational inevitability and absolute invariability.; multiple unity was expressed in self-completedness and independent parallel of discrete forms and harmony of emphasized individual elements in a totality. Applying these layout characteristics of the Renaissance Classicism Architectural style and to see their individual expressive features, I found out that in adopting layout principles of the Renaissance Classicism Architecture to modern fashion, it turned out to be an emphasis of individual silhouettes, a flattened space, completed objects, organic harmony among independent parts: the emphasis of individual silhouettes was expressed in individual definitiveness of formative lines of clothes in accordance with body joints and an emphasis on formative lines of clothes; the flattened space was marked by single layer structure, planarity of elements of clothes, and listing arrangement by appropriate proportion.; the completedness of the objects was expressed by the stationary state where overall image is fixed, the construction of homogeneous and complete space, and absolute inevitability of internal layout in proportion; lastly, organic harmony of independent parts was stressed in independent completedness of each detail, and organic harmony of the whole. The expressive features would lead to a unique expression style of linear emphasis, proportion, constructive forms, and two-dimensional arrangement. The meaning of this study is follows: The characteristics of art school of thought are given shape by appling & analysing the architectural layout principles of historical art school of thought to modern fashion in the view point of formal construction dimension. The applied possibility of historical art school of thought as the source of inspiration about the fashion design is extended.

Groundwater Flow Analysis around Hydraulic Excavation Damaged Zone (수리적 굴착손상영역에서의 지하수유동 특성에 관한 연구)

  • Park, Jong-Sung;Ryu, Dong-Woo;Ryu, Chang-Ha;Lee, Chung-In
    • Tunnel and Underground Space
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    • v.17 no.2 s.67
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    • pp.109-118
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    • 2007
  • The excavation damaged zone (EDZ) is an area around an excavation where in situ rock mass properties, stress condition. displacement. groundwater flow conditions have been altered due to the excavation. Various studies have been carried out on EDZ, but most studies have been focused on the mechanical bahavior of EDZ by in situ experiment. Even though the EDZ could potentially form a high permeable pathway of groundwater flow, only a few studies were performed on the analysis of groundwater flow in EDZ. In this study, the' hydraulic EDZ' was defined as the rock Lone adjacent to the excavation where the hydraulic aperture has been changed due to the excavation. And hydraulic EDZ (hydraulic aperture changed zone) estimated by two-dimensional DEM program was considered in three-dimensional DFN model. From this approach the groundwater flow characteristics corresponding to hydraulic aperture change were examined. Together. a parametric study was performed to examine the boundary conditions that frequently used in DFN analysis such as constant head or constant flux condition. According to the numerical analysis, hydraulic aperture change induced by the hydraulic-mechanical interaction becomes one of the most important factors Influencing the hydraulic behavior of jointed rock masses. And also from this study, we suggest the proper boundary condition in three-dimensional DFN model.

DEM numerical study for the effect of scraper direction on shield TBM excavation in soil (개별요소법을 이용한 스크래퍼 비트방향이 토사지반에서의 쉴드 TBM 굴진에 끼치는 영향 연구)

  • Lee, Gi-Jun;Kim, Huntae;Kwon, Tae-Hyuk;Cho, Gye-Chun;Kang, Shin-Hyun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.5
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    • pp.689-698
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    • 2019
  • In tunnel excavation by TBMs, a cutterhead, which practically excavates the ground, is an important part directly affecting net penetration rate. Most of the researches on the cutterhead design that have been carried out until now are on the cutter arrangement. It is difficult to find a study for the effect of the scraper installation direction on TBM excavation although same cutterheads except for direction of the scraper are used in Korea. Therefore, this paper shows how the direction of scraper installation affects shield-TBM excavation. Discrete element method was used to identify the effect of scraper installation direction on shield-TBM excavation. When the scraper installation direction was outward, the amount of particles per unit time flowed into the cutter head opening was smaller than when the scraper installation direction was inward, and more loads were applied to the cutterhead.

Review on Discontinuum-based Coupled Hydro-Mechanical Analyses for Modelling a Deep Geological Repository for High-Level Radioactive Waste (고준위방사성폐기물 심층처분장 모델링을 위한 불연속체 기반 수리-역학 복합거동 해석기법 현황 분석)

  • Kwon, Saeha;Kim, Kwang-Il;Lee, Changsoo;Kim, Jin-Seop;Min, Ki-Bok
    • Tunnel and Underground Space
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    • v.31 no.5
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    • pp.309-332
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    • 2021
  • Natural barrier systems surrounding the geological repository for the high-level radioactive waste should guarantee the hydraulic performance for preventing or delaying the leakage of radionuclide. In the case of the behavior of a crystalline rock, the hydraulic performance tends to be decided by the existence of discontinuities, so the coupled hydro-mechanical(HM) processes on the discontinuities should be characterized. The discontinuum modelling can describe the complicated behavior of discontinuities including creation, propagation, deformation and slip, so it is appropriate to model the behavior of a crystalline rock. This paper investigated the coupled HM processes in discontinuum modelling such as UDEC, 3DEC, PFC, DDA, FRACOD and TOUGH-UDEC. Block-based discontinuum methods tend to describe the HM processes based on the fluid flow through the discontinuities, and some methods are combined with another numerical tool specialized in hydraulic analysis. Particle-based discontinuum modelling describes the overall HM processes based on the fluid flow among the particles. The discontinuum methods that are currently available have limitations: exclusive simulations for two-dimension, low hydraulic simulation efficiency, fracture-dominated fluid flow and simplified hydraulic analysis, so it could be improper to the modelling the geological repository. Based on the concepts of various discontinuum modelling compiled in this paper, the advanced numerical tools for describing the accurate coupled HM processes of the deep geological repository should be developed.

Numerical analysis on the estimation of optimal disc cutter angle in transition cutter zone (전이 구간(트렌지션 커터존)의 최적 디스크커터 각도 산정에 관한 수치해석 연구)

  • Lee, Sang Yun;Song, Ki-il
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.23 no.1
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    • pp.1-12
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    • 2021
  • In the design of a tunnel boring machine (TBM), the excavation efficiency of the equipment depends on the design of the cutter head, which is directly in contact with the ground. Especially, the allocation of disc cutter is crucial issue. Disc cutters can be divided into center cutter zone, inner cutter zone and transition cutter zone depending on where they are placed. Many studies have been conducted to identify optimal cutting conditions for face cutters. However, research to determine the optimal cutting conditions for the transition cutter has been relatively incomplete. In this study, to identify the optimal cutting conditions for the transition cutter, numerical analysis using discrete element method was performed, and the specific energy curve according to the angle between the transition cutters was drawn to find out the optimum cutting conditions. The results show that the angle between the transition cutters showing minimum specific energy in the transition cutter zone is 9°. Transition cutter zone was divided into three sections according to the slope angle of the transition cutter. It is also found that, the greater the slope angle of the transition cutter. This finding shows good agreement with the present design of transition cutter zone.

Fracture Behaviors of Jointed Rock Model Containing an Opening Under Biaxial Compression Condition (이축압축 조건에서 공동이 존재하는 유사 절리암반 모델의 파괴 거동)

  • SaGong, Myung;Yoo, Jea-Ho;Park, Du-Hee;Lee, J.S.
    • Journal of the Korean Geotechnical Society
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    • v.25 no.10
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    • pp.17-30
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    • 2009
  • Underground construction such as tunneling can induce damages on the surrounding rock mass, due to the stress concentration of in situ stresses and excessive energy input during construction sequence, such as blasting. The developed damage on the rock mass can have substantial influence on the mechanical and hydraulic behaviors of the rock masses around a tunnel. In this study, investigation on the generation of damage around an opening in a jointed rock model under biaxial compression condition was conducted. The joint dip angles employed are 30, 45, and 60 degrees to the horizontal, and the synthetic rock mass was made using early strength cement and water. From the biaxial compression test, initiation and propagation of tensile cracks at norm to the joint angle were found. The propagated tensile cracks eventually developed rock blocks, which were dislodged from the rock mass. Furthermore, the propagation process of the tensile cracks varies with joint angle: lower joint angle model shows more stable and progressive tensile crack propagation. The development of the tensile crack can be explained under the hypothesis that the rock segment encompassed by the joint set is subjected to the developing moment, which can be induced by the geometric irregularity around the opening in the rock model. The experiment results were simulated by using discrete element method PFC 2D. From the simulation, as has been observed from the test, a rock mass with lower joint angle produces wider damage region and rock block by tensile cracks. In addition, a rock model with lower joint angle shows progressive tensile cracks generation around the opening from the investigation of the interacted tensile cracks.

Numerical Simulation of Spatiotemporal Distribution of Chaff Clouds for Warship Defense using CFD-DEM Coupling (CFD-DEM 연동을 통한 함정용 채프운의 시공간 분포 해석)

  • Uk Jin Jung;Moonhong Kim;Dongwoo Sohn
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.36 no.2
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    • pp.93-103
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    • 2023
  • Warships widely spread numerous chaffs using a blast, which form chaff clouds that create false radar cross-sections to deceive enemy radars. In this study, we established a numerical framework based on a one-way coupling of computational fluid dynamics and discrete element method to simulate the spatiotemporal distribution of chaff clouds for warships in the air. Using the framework, we investigated the effects of wind, initial chaff cartridge angle, and blast pressure on the distribution of chaff clouds. We observed three phases for the chaff cloud diffusion: radial diffusion by the explosion, omnidirectional diffusion by turbulence and collision, and gravity-induced diffusion by the difference in the fall speed. The wind moved the average position of the chaff clouds, and the diffusion due to drag force did not occur. The direction of radial diffusion by the explosion depended on the initial angle of the cartridge, and a more vertical angle led to a wider distribution of the chaffs. As the blast pressure increased, the chaff clouds spread out more widely, but the distribution difference in the direction of gravity was not significant.

Response Analysis of Nearby Structures with the Consideration of Tunnel Construction and Ground Conditions (터널시공 및 지반조건을 반영한 인접구조물의 거동분석)

  • Son, Moorak;Yun, Jongcheol
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.6C
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    • pp.255-263
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    • 2010
  • This paper investigates the effects of tunnelling-induced ground movements on nearby structures, considering soil-structure interactions of different construction (ground loss) and soil characteristics. The response of four-story block structures, which are subjected to tunnelling-induced ground movements, has been investigated in different construction (ground loss) and soil conditions using numerical analysis. The structures for numerical analysis has been modelled using Discrete Element Method (DEM) to have real cracks when the shear and tensile stress exceed the maximum shear and tensile strength. The response of four-story block structures has been investigated with a ground movement magnitude and compared in terms of construction (ground loss) and soil conditions considering the magnitude of deformations and cracks in structures. In addition, the damage levels, which are possibly induced in structures, has been provided in terms of construction (ground loss) and soil conditions using the state of strain damage estimation criterion (Son and Cording, 2005). The results of this study will provide a background for better understandings for controlling and minimizing building damage on nearby structures due to tunnelling-induced ground movements.