• 제목/요약/키워드: Spreading Radius

검색결과 16건 처리시간 0.021초

Simple solutions of an opening in elastic-brittle plastic rock mass by total strain and incremental approaches

  • Park, Kyungho
    • Geomechanics and Engineering
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    • 제13권4호
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    • pp.585-600
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    • 2017
  • This study deals with simple solutions for a spherical or circular opening excavated in elastic-brittle plastic rock mass compatible with a linear Mohr-Coulomb (M-C) or a nonlinear Hoek-Brown (H-B) yield criterion. Based on total strain approach, the closed-form solutions of stresses and displacement are derived simultaneously for circular and spherical openings using original H-B and M-C yield criteria. Two simple numerical procedures are proposed for the solution of generalized H-B and M-C yield criteria. Based on incremental approach, the similarity solution is derived for circular and spherical openings using generalized H-B and M-C yield criteria. The classical Runge-Kutta method is used to integrate the first-order ordinary differential equations. Using three data sets for M-C and H-B models, the results of the radial displacements, the spreading of the plastic radius with decreasing pressure, and the radial and circumferential stresses in the plastic region are compared. Excellent agreement among the solutions is obtained for all cases of spherical and circular openings. The importance of the use of proper initial values in the similarity solution is discussed.

다양한 조건하에서 모세관력 불균형에 의해 구동되는 수평 표면 위의 액적 거동 (Behavior of Liquid Droplet Driven by Capillarity Force Imbalance on Horizontal Surface Under Various Conditions)

  • 명현국;권영후
    • 대한기계학회논문집B
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    • 제39권4호
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    • pp.359-370
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    • 2015
  • 본 연구는 다양한 조건하에서 모세관력 불균형에 의해 구동되는 수평 표면 위의 액적 거동을 수치해석적으로 연구한 것이다. 액적 거동은 자체개발 코드(PowerCFD)를 사용하여 수치해석하였다. 수치해석에 사용된 코드는 보존적인 압력기반 유한체적방법에 기초한 비정렬 셀 중심 방법 및 VOF 방법에 체적포착법인 CICSAM을 채용하고 있다. 상세한 액적 거동이 다양한 초기 액적형상, 접촉각 및 표면장력(또는 Bond 수)의 조건하에서 얻어졌다. 또한 액적 이송 메커니즘이 액적 형상에 대한 수치해석 결과로부터 검토되었다.

연신내 성당 리모델링 구축 프로젝트 (Remodeling Project of the 'Yeonsinae' Catholic Church)

  • 배강희;이혁준
    • 한국실내디자인학회:학술대회논문집
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    • 한국실내디자인학회 2006년도 춘계학술발표대회 논문집
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    • pp.53-54
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    • 2006
  • Recently with increasing interest in the operation of life cycle, building remodeling business is spreading like a fashion. Keeping pace with the trend, the present project carried out the remodeling of an existing neighborhood facility into a religious facility based on the concepts of remodeling, reform and renovation. Basic requirements were overcoming spatial limitations, solving structural problems, meeting various functional needs, and securing a spatial size, and the project designed the interior of the building according to these requirements suggested by the owner. To overcome the low floor height of the existing space, the main sanctuary on the 1st floor had the ceiling in the form of a slant and installed indirect lighting into the resulting gaps, maximizing the depth and width of the space visually. The subsidiary sanctuary on the first basement was finished with red bricks, forming an arch using the bricks, to create religious atmosphere. However, considering the low floor height as in the 1st floor and the ceiling even lowered by the arch structure, the arch was formed threefold and the radius of the curvature of the arch was enlarged to secure a spacious feeling. The outer appearance was finished with granite on existing structure to save the cost of construction. In addition to the use of the finishing material, the structure of the arch and the frame of the opening part and the finishing of the walls were expressed with uneven surface in order to avoid the plainness of the appearance.

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수정된 CIP방법을 이용한 벽면 충돌 후 액적의 퍼짐 현상에 대한 수치해석 연구 (NUMERICAL STUDY ON DROPLET SPREAD MOTION AFTER IMPINGEMENT ON THE WALL USING IMPROVED CIP METHOD)

  • 손소연;고권현;이성혁;유홍선
    • 한국전산유체공학회지
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    • 제15권4호
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    • pp.25-31
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    • 2010
  • Interface tracking of two phase is significant to analyze multi-phase phenomena. The VOF(Volume of Fluid) and level set are well known interface tracking method. However, they have limitations to solve compressible flow and incompressible flow at the same time. CIP(Cubic Interpolate Propagation) method is appropriate for considering compressible and incompressible flow at once by solving the governing equation which is divided up into advection and non-advection term. In this article, we analyze the droplet impingement according to various We number using improved CIP method which treats nonlinear term once more comparison with original CIP method. Furthermore, we compare spread radius after droplet impingement on the wall with the experimental data and original CIP method. The result using improved CIP method shows the better result of the experiments, comparison with result of original CIP method, and it reduces the mass conservation error which is generated in the numerical analysis comparison with original CIP method.

모노펄스안테나 시스템에 적용되는 2중 반사경 설계 (Design of Dual Reflector for Monopulse antennas System)

  • 김원섭
    • 대한전자공학회논문지TC
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    • 제45권1호
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    • pp.85-90
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    • 2008
  • 본 논문에서는 모노펄스 안테나 시스템에 적용되는 2중 반사경에 관하여 연구하였다. 연구 결과 주반사판의 효율이 70% 이상인 경우 반사경의 크기가 설계에 사용되는 최저 주파수(11.7GHz)의 30파장(약77cm)이면 최저주파수의 이득은 37.9dBi, 최대 주파수(12.7GHz)에서는 38.6dBi의 이득을 얻을 수 있다. 또한 부반사판의 성능 개선을 위한 방안으로 반지름 D이고 초점거리 $F_e$인 경우 초점거리 대 지름의 비가 더 클수록 원거리 장에서의 교차편파가 개선되며 반사판의 테두리에서의 구면 확산손실이 감소한다. 또한, 급전 안테나의 측면 변위($x_sy_s$평면에서)에 따른 방사패턴의 약화 정도가 더 작아지기 때문에 주빔의 주사 성능이 개선됨을 확인하였다.

경관훼손지의 생태적 복구방안에 관한 연구 (A Study on the Ecological Restoration Strategies for the Disturbed Landscapes)

  • 김남춘
    • 한국환경복원기술학회지
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    • 제1권1호
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    • pp.28-44
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    • 1998
  • This study was conducted to suggest the ecological restoration strategies for the disturbed landscapes by theoretical study. Especially, it is aimed to suggest three objectives for restoration by using native plants ; (1) prevention or reduction of wind and water erosion, (2) provision of food and cover for variety of animal species, (3) improvement of the visual or aesthetic quality of disturbed sites. The main results were summarized as follows. 1. Cooperation between restoration ecologists and restoration practitioners is needed to delineate a scientific approach to restoration ; (1) Being aware of published literature that describes similar work and/or establish general principles. (2) Preparedness to carry out proper experiments to test ideas. (3) Preparedness to monitor fundamental parameters in a restoration scheme. (4) Providing information about the behavior of species. (5) Publish results. 2. There are three models of succession in theories of plant succession. The tolerance and facilitation models were recommended to ecological restoration. The inhibition model applies in most secondary succession, but the actual species which are introduced first may inhibit the germination and growth of slower-growing species, or they may prevent the growth of other species whose propagules arrive later. 3. The objectives of erosion control, wildlife habitat provision, and visual quality improvement are not mutually exclusive. However, many revegetation practices in the past have emphasized one of these aspects at the expense of the others. 4. A native plant community can be the model of ecological restoration. By stylization/abstraction of native plant community, trying to learn the most essential characteristics of community types - environmental factors ; dominant, prevalent, and "visual essence" species composition - in order to use such information in restoration. 5. After developing mass/spaces plan, match plant communities to the mass/space plan. In utilizing community grouping, there needs aesthetic ability to understand design elements. 6. Several hydrophytes such as Pennisetum saccharifluous, Themeda triandra, Cirsium pendulum show relatively good germination rates. In case of mesophytes and xerophytes, Arundinella hina, Artemisia princeps, Oenothera odorata and legumes seem to have quick-germinating abilities at barren sites. Pinus thunbergii, Rhus chinensis, Evodia daniellii, Alnus firma and Albizzia julibrissin can be considered as "late succession" woody plants because they show low germinating rates and slow growing habitat. 7. The seeds used for restoration should be collected within a certain radius of where it will be planted. Consideration in genetic issues in the collection and use of germplasm can increase the odds for successful restoration efforts. 8. The useful model in the "drift" pattern occurs so abundantly in naturally evolving landscapes. As one species diminishes in density, a second or third species are increased. Thus, dynamic interactions between species are created. Careful using of "drift phenomenon" in planting was recommended. 9. Virtually no stand of vegetation today is immune from the introduction and/or spreading of exotic species. Therefore, the perpetuation of a restored sites requires conscious monitoring and management. Thus, management would be the most important process in ecological restoration. 10. In order to keep the sites "natural", alternative management strategies would be applied in management ; Atenative management strategies are decelerating successional process, accelerating successional processes or modifying species composition. As management tools, mechanical, chemical, biological or environmental factor manipulation, e.g., fire could be used.

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