• Title/Summary/Keyword: Grid Structure

Search Result 866, Processing Time 0.025 seconds

CAD Interface using Topology Optimization (위상최적설계 결과를 이용한 CAD 인터페이스)

  • Kim, Seong-Hoon;Min, Seung-Jae;Lee, Sang-Hun
    • Korean Journal of Computational Design and Engineering
    • /
    • v.14 no.4
    • /
    • pp.281-289
    • /
    • 2009
  • Topology optimization has been widely used for the optimal structure design for weight reduction and high performance. Since the result of three-dimensional topology optimization is represented by the discrete material distribution in finite elements, it is hard to interpret from a design point of view. In this paper, the method for interpreting three-dimensional topology optimization resuIt into a series of cross-sectional curve representation is proposed and interfaced with the existing CAD system for the practical use. The concept of node density and virtual grid is introduced to transform element density values into grid density and material boundaries in each cross section are identified based on the element volume rate to satisfy the amount of material specified in the original design intent. Design exampIes show that three-dimensional topology result can be converted into a form of curve CAD model and the seamless interface with CAD software can be achieved.

Computational Grid Generation for Aero-Performance Prediction of Multi-staged Axial Compressors (다단축류압축기의 공력성능 예측용 계산격자 생성기법 연구)

  • Chung, H.T.;Kim, J.S.
    • Journal of Power System Engineering
    • /
    • v.2 no.1
    • /
    • pp.39-44
    • /
    • 1998
  • Computational grids used in the numerical simulation of multi staged turbomachinery flow fields are generated. A multiblock structure simplifies the creation of structured H-grids about complex turbomachinery geometries and facilitate the creation of a grid for multi-row topologies. The numerical algorithm adopts the combination of the algebraic and elliptic method to create the internal grids efficiently and quickly. The input module is made of the results of the preliminary design, i.e., flow-path, aerodynamic conditions along the spanwise direction, and the blade profile data. The final grids generated from each module of the system are used as the preprocessor for the performance prediction of the single row cascades and the flow simulation inside the multi staegd blade passage. Application to low pressure compressor of industrial gas turbine engines was demonstrated to be very reliable and practical in support of design activities.

  • PDF

Application of Vertical Grid-nesting to the Tropical Cyclone Track and Intensity Forecast

  • Kim, Hyeon-Ju;Cheong, Hyeong-Bin;Lee, Chung-Hui
    • Journal of the Korean earth science society
    • /
    • v.40 no.4
    • /
    • pp.382-391
    • /
    • 2019
  • The impact of vertical grid-nesting on the tropical cyclone intensity and track forecast was investigated using the Weather Research and Forecast (WRF) version 3.8 and the initialization method of the Structure Adjustable Balanced Bogus Vortex (SABV). For a better resolution in the central part of the numerical domain, where the tropical cyclone of interest is located, a horizontal and vertical nesting technique was employed. Simulations of the tropical cyclone Sanba (16th in 2012) indicated that the vertical nesting had a weak impact on the cyclone intensity and little impact on the track forecast. Further experiments revealed that the performance of forecast was quite sensitive to the horizontal resolution, which is in agreement with previous studies. The improvement is due to the fact that horizontal resolution can improve forecasts not only on the tropical cyclone-scale but also for large-scale disturbances.

A Study on Structure of Middleware for Effective Cloud Infra and Service Mashup (효율적인 클라우드 인프라 및 서비스 메쉬업을 위한 미들웨어 구조 연구)

  • Park, Seung-Kyun;Park, Yong-Sung;Sung, Gi-Won;Youn, Chan-Hyun
    • Proceedings of the Korea Information Processing Society Conference
    • /
    • 2011.04a
    • /
    • pp.1549-1550
    • /
    • 2011
  • 현재의 다양한 메쉬업(Mashup) 기술은 웹에서 제공되는 데이터, 웹서비스, RSS/Atom 피드 등에만 사용이 국한되어 있기 때문에, 클라우드 환경에 적용하게 되면 SaaS(Software as a Service) 형태의 서비스로만 구성되게 된다. 하지만, 클라우드에서는 인프라 자원들도 서비스의 형태로 접근될 수 있으며, 이를 이용한 메쉬업이 가능하다. 이에 본 논문에서는 클라우드의 인프라 자원 및 SaaS 형태의 서비스를 메쉬업 할 수 있는 효율적인 미들웨어 구조를 제안하고자 한다.

A Study on Tensile Strength Dependent on Variation of Output Condition of the X-shape Infill Pattern using FFF-type 3D Printing (융합 필라멘트 제조 방식의 3D 프린팅을 이용한 X자 형상 내부 채움 패턴의 출력 옵션 변화에 따른 인장강도 연구)

  • D. H. Na;H. J. Kim;Y. H. Lee
    • Transactions of Materials Processing
    • /
    • v.33 no.2
    • /
    • pp.123-131
    • /
    • 2024
  • Plastic, the main material of FFF-type 3D printing, exhibits lower strength compared to metal. research aimed at increasing strength is needed for use in various industrial fields. This study analyzed three X-shape infill patterns(grid, lines, zigzag) with similar internal lattice structure. Moreover, tensile test considering weight and printing time was conducted based on the infill line multiplier and infill overlap percentage. The three X-shape infill patterns(grid, lines, zigzag) showed differences in nozzle paths, material usage and printing time. When infill line multiplier increased, there was a proportional increase in tensile strength/weight and tensile strength/printing time. In terms of infill overlap percentage, the grid pattern at 50% and the zigzag and lines patterns at 75% demonstrated the most efficient performance.

A Study on Geotechnical Lineament Analysis by Image Processing Method (영상사진을 이용한 지반공학적인 선구조분석 연구)

  • 이수곤;금동헌
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2000.11a
    • /
    • pp.593-600
    • /
    • 2000
  • Most of ground investigations can be grasped geological distribution which like rock name, geological structure, soil condition, underwater condition, land slide, ground cave-in, ground collapse by geological survey. But geological survey is limited to part region geological structure, not wide region. Therefore, Image Processing Method must need to grasp wide region geological structure. The object of this research is presented analysis data of geotechnical engineering in first step investigation.

  • PDF

Sliding Mode Controller Design Based On The Fuzzy Observer For Uncertain Nonlinear System (불확실한 비선형 시스템의 퍼지 관측기 기반의 슬라이딩 모드 제어기 설계)

  • 서호준;박장현;허성희;박귀태
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2000.10a
    • /
    • pp.284-284
    • /
    • 2000
  • In adaptive fuzzy control systems. fuzzy systems are used to approximate the unknown plant nonlinearities. Until now. most of the papers in the field of controller design for nonlinear system using fuzzy systems considers the affine system with fixed grid-rule structure based on system state availability. This paper considers observer-based nonlinear controller and dynamic fuzzy rule structure. Adaptive laws for fuzzy parameters for state observer and fuzzy rule structure are established so that the whole system is stable in the sense of Lyapunov.

  • PDF

Nonlinear stability analysis of a radially retractable hybrid grid shell in the closed position

  • Cai, Jianguo;Zhang, Qian;Jiang, Youbao;Xu, Yixiang;Feng, Jian;Deng, Xiaowei
    • Steel and Composite Structures
    • /
    • v.24 no.3
    • /
    • pp.287-296
    • /
    • 2017
  • The buckling capacity of a radially retractable hybrid grid shell in the closed position was investigated in this paper. The geometrically non-linear elastic buckling and elasto-plastic buckling analyses of the hybrid structure were carried out. A parametric study was done to investigate the effects rise-to-span ratio, beam section, area and pre-stress of cables, on the failure load. Also, the influence of the shape and scale of imperfections on the elasto-plastic buckling loads was discussed. The results show that the critical buckling load is reduced by taking account of material non-linearity. Furthermore, increasing the rise-to-span ratio or the cross-section area of steel beams notably improves the stability of the structure. However, the cross section area and pre-stress of cables pose negligible effect on the structural stability. It can also be found that the hybrid structure is highly sensitive to geometric imperfection which will considerably reduce the failure load. The proper shape and scale of the imperfection are also important.

Numerical Simulation on the Greenwater Impact Load of Offshore Structure in Regular Waves (규칙파 중 해양구조물의 갑판침입수 충격하중에 관한 수치시뮬레이션)

  • Kang, Ui-Ha;Lee, Young-Gill;Yang, In-Jun;Kim, Ki-Yong;Joo, Young-Seok;Park, Jeong-Ho
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.54 no.6
    • /
    • pp.492-500
    • /
    • 2017
  • In the study, numerical simulation on the greenwater impact load of free surface offshore structure in the regular waves using fixed cartesian grid system and Modified Marker-Density (MMD) method were carried out and the results were reviewed. In order to compare numerical simulation and experimental results, the FPSO with the scale ratio of 1/100 model ship with fixed rectangular deck was selected and turbulence characteristic of the flow was considered by applying the Sub-Grid Scale (SGS) in laminar flow. As a result, it is reviewed how the greenwater impact load inflowed from bow in regular headsea wave influence the flow on the deck and the flow characteristic by numerical simulation and the experiment results were compared and reviewed. Based on this study, it would be useful to numerically study the effect of greenwater on offshore structure.

Data Dissemination Protocol Considering Target Mobility in Ubiquitous Sensor Network (유비쿼터스 센서 네트워크 환경에서 감지대상의 이동성을 고려한 데이터 전달 프로토콜)

  • Suh Yu-Hwa;Kim Ki-Young;Shin Young-Tae
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.31 no.3A
    • /
    • pp.311-320
    • /
    • 2006
  • This paper proposes DDTM for USN having end-point mobility. The existing network protocols did not consider target's and sink's mobility. So it requires flooding and path update whenever targets or sinks move. This can lead to drain battery of sensors excessively and decrease lifetime of USN. DDTM is the protocol based on TTDD considering sink's mobility. TTDD provides sink's mobility efficiently by using the grid structure, but it requires the high energy because of reconstructing the grid structure whenever targets move. In this way, the proposed protocol can decrease a consumption of energy, since it reuses the existing grid structure of TTDD, if the target moves in local cell. We compare DDTM with TTDD under the total message and the energy consumption by using a discrete analytical model for cost analysis. Analytical results demonstrated that our proposed protocol can provide the higher efficiency on target's mobility.