• Title, Summary, Keyword: 링해석법

Search Result 260, Processing Time 0.055 seconds

Application of resistivity monitoring with tunnel excavation area (터널 굴착에 따른 전기비저항 모니터링 기술 적용)

  • Ahn, Hee-Yoon;Jeong, Jae-Hyeung;Cho, In-Ky;Kim, Jung-Ho;Rae, Gyu-Jin
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.10 no.4
    • /
    • pp.405-420
    • /
    • 2008
  • Resistivity survey is one of the widely used methods for the investigation of stability of the ground or bedrock around tunnel and is also used as an essential base data for stability and reduction of construction cost through first-hand approximation of rock quality at design step. Generally, the analysis of resistivity survey data is performed by single measurement. When distribution variation of groundwater around a tunnel over time is necessary for maintenance of a tunnel, resistivity monitoring is very useful survey method to grasp distribution variation of groundwater. So we performed the grid line resistivity survey to monitoring resistivity variation for six times. And we also tried to evaluate application possibility of the resistivity monitoring for construction safety through providing detailed information on fault zones.

  • PDF

Time-lapse Inversion of 2D Resistivity Monitoring Data (2차원 전기비저항 모니터링 자료의 시간경과 역산)

  • Kim, Ki-Ju;Cho, In-Ky;Jeoung, Jae-Hyeung
    • Geophysics and Geophysical Exploration
    • /
    • v.11 no.4
    • /
    • pp.326-334
    • /
    • 2008
  • The resistivity method has been used to image the electrical properties of the subsurface. Especially, this method has become suitable for monitoring since data could be rapidly and automatically acquired. In this study, we developed a time-lapse inversion algorithm for the interpretation of resistivity monitoring data. The developed inversion algorithm imposes a big penalty on the model parameter with small change, while a minimal penalty on the model parameter with large change compared to the reference model. Through the numerical experiments, we can ensure that the time-lapse inversion result shows more accurate and focused image where model parameters have changed. Also, applying the timelapse inversion method to the leakage detection of an embankment dam, we can confirm that there are three major leakage zones, but they have not changed over time.

Three-Dimensional Limit Equilibrium Stability Analysis of the Irregularly Shaped Excavation Comer with Skew Soil Nailing System

  • Kim, Hong Taek;Par
    • Geotechnical Engineering
    • /
    • v.14 no.3
    • /
    • pp.73-94
    • /
    • 1998
  • In the present study, a method of the three-dimensional limit equilibrium stability analysis of shape of the potential failure wedge for the concave-shaped excavation corner is assumed on the basis of the results of the FLACSU program analysis. Estimation of the three-dimensional seepage forces expected to act on the failure wedge is made by solving the three-dimensional continuity equation of flow with appropriate boundary conditions. By using the proposed method of three-dimensional stability analysis of the concave-shaped excavation corner, a parametric study is performed to examine the reinforcement effect of skew soil nailing system, range of the efficient skew angles and seepage effect on the overall stability. Also examined is the effect of an existence of the right-angled excavation corner on three-dimensional deflection behaviors of the convex-shaped skew soil nailing walls. The results of analyses of the convexshaped excavation corner with skew soil nailing system is further included to illustrate the effects of various design parameters for typical patterns of skew nails reinforcement system.

  • PDF

최적화된 대면적 스퍼터링 캐소드를 이용한 Si/SiO2 박막 제조 및 특성 평가

  • Kim, Yeong-Tae;Park, Seung-Il;Kim, Tae-Hyeong;No, Tae-Uk;Kim, Man-Tae;Park, Hyeong-Sun;Son, Seon-Yeong;Yun, Seung-Jin;Jeon, Mu-Hyeon
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • /
    • pp.459-459
    • /
    • 2010
  • 대면적 마그네트론 스퍼터링 캐소드를 이용하여 고효율 스퍼터링을 실현하기 위해서는 진공 상태에서 하전입자의 손실을 최소화하여 플라즈마 내에 많은 입자를 구속하는 기술이 요구된다. 본 연구에서는 고효율 특성을 갖는 대면적 캐소드($127mm{\times}900mm$) 설계를 위해 유한요소법(Finite Element Method) 수치해석 알고리즘을 이용한 3차원 전자장(Magnetostatic) 시뮬레이션 툴을 이용하여 최적화된 캐소드를 설계하였다. 캐소드 타겟 배면에 생성되는 자기장의 3차원 특성 해석을 통해 타겟효율에 가장 큰 영향을 미치는 자속밀도의 관계를 분석하였다. 고효율 캐소드 구조 설계를 위해서는 타겟 배면에 평행한 자속밀도의 분포를 최대한 확보를 것이 매우 중요하다. 이러한 특성을 확보하기 위하여 캐소드 내부에 장착되는 자석 크기 및 특성에 따른 자속밀도 특성을 해석하였다. 개발된 마그네트론 캐소드에 Si 타겟을 장착하였다. 캐소드 특성 평가를 위해 Ar 분위기 및 $O_2$를 동시에 인가하여 Si 및 $SiO_2$ 박막을 유리기판에 코팅하였다. 코팅된 박막의 특성 평가는 결정구조와 두께에 따른 투과율 및 반사율 측정을 수행하였다. Si 박막의 경우, 갈색의 코팅막을 형성하였으며, $SiO_2$의 경우, 투명한 박막으로 증착되었고 조성분석(EDXS)에 의해 $SiO_2$로 잘 코팅되었음을 확인할 수 있었다. 그리고, $SiO_2$가 코팅된 막의 투과율은 유리기판에 비해 1% 정도 향상되었음을 확인할 수 있었다. 마그네트론 캐소드 성능은 Si 타겟의 erosion 형상 분석과 3차원 유한요소법 프로그램을 이용한 자기장 분석을 통해 비교 분석하였다.

  • PDF

The Prediction of Yield Load in Circular Tubular T-type Cross Sections on the Truss Structures (강관트러스의 T형 격점부의 항복하중 예측에 관한 연구)

  • Park, Il Min
    • Journal of Korean Society of Steel Construction
    • /
    • v.13 no.1
    • /
    • pp.9-18
    • /
    • 2001
  • many steel tubular truss as roof structures are used of the large span structures Steel tubular sectioned truss has the structural merits in compared with other sections such as H, L-shape sections However it occurs local buckling at the joint of branch in truss and it makes the deterioration of loading capacity Loading capacity and deformation characteristics of truss joints are very complicate so it is very hard to predict exact solution of them Therefore this thesis dealt with T-type joints of steel circular hollow sectioned truss. A series of experimental scheme were planned and mainly experimental parameters were : ratio of diameter of branch-diameter of main chord(d/D). diameter-thickness(T/D) of main chord. In this paper predicted yield load capacity using by closed ring analysis method additionally compared with that of suggested by closed ring analysis method additionally compared with that of suggested by other countries.

  • PDF

Probabilistic Risk Assessment of Coastal Structures using LHS-based Reliability Analysis Method (LHS기반 신뢰성해석 기법을 이용한 해안구조물의 확률론적 위험도평가)

  • Huh, Jung-Won;Jung, Hong-Woo;Ahn, Jin-Hee;An, Sung-Wook
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.19 no.6
    • /
    • pp.72-79
    • /
    • 2015
  • An efficient and practical reliability evaluation method is proposed for the coastal structures in this paper. It is capable of evaluating reliability of real complicated coastal structures considering uncertainties in various sources of design parameters, such as wave and current loads, resistance-related design variables including Young's modulus and compressive strength of the reinforced concrete, soil parameters, and boundary conditions. It is developed by intelligently integrating the Latin Hypercube sampling (LHS), Monte Carlo simulation (MCS) and the finite element method (FEM). The LHS-based MCS is used to significantly reduce the computational effort by limiting the number of simulation cycles required for the reliability evaluation. The applicability and efficiency of the proposed method were verified using a caisson-type breakwater structure in the numerical example.

Analysis of the Propagation Characteristics of Two Dimensional Ultrasonic Fields in Layered Media (층상매질에서의 이차원 초음파음장 전파특성해석)

  • 윤혁준
    • Proceedings of the Acoustical Society of Korea Conference
    • /
    • /
    • pp.445-448
    • /
    • 1998
  • 고유음향 임피던스가 다른 물질이 층상구조를 이루고 있는 매질내에서 임의의 한 층에 형성된 이차원 초음파 음장이 다른 매질로 전파될 때에의 특성을 각스펙트럼법에 의해 해석하였다. 음원으로서는 baffle된 원형 트랜스듀서를, 층상구조를 매질로서는 물과 생체조직(지방)의 경계를 각각 고려하였다. 해석에 있어서는 먼저 각스펙트럼 분해요소, 즉, 음원의 크기 및 거리에 의존하는 기준음장의 최적 크기와 샘플링 간격을 균질매질을 이용하여 결정한 다음, 그 요소를 층상매질에 적용하였다. 그 결과, 경계면에서의 입사각(공간주파수)의 의존하는 투과계수에 입사음장의 곱으로 나타내어지는 투과음장은 각스펙트럼법에 의해 짧은 시간내에 정도 높게 산출될 수 있음을 보인다.

  • PDF

Piston-Ring Lubrication Analysis Using Finite Element Method (유한 요소법을 이용한 피스턴 링의 윤활 해석)

  • 심현해;권오관
    • Tribology and Lubricants
    • /
    • v.8 no.1
    • /
    • pp.38-43
    • /
    • 1992
  • In solving the Reynolds equation in dynamically loaded bearing problem, it is almost impossible to find the squeeze velocity and the cavitation region by analytical method. Finite Element Method was applied to the piston-ring lubrication analysis to solve the complementary problem. The method was very efficient and any convergence problem was not encountered.

Reliability Analysis Using Dimension Reduction Method with Variable Sampling Points (가변적인 샘플링을 이용한 차원 감소법에 의한 신뢰도 해석 기법)

  • Yook, Sun-Min;Min, Jun-Hong;Kim, Dong-Ho;Choi, Dong-Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.33 no.9
    • /
    • pp.870-877
    • /
    • 2009
  • This study provides how the Dimension Reduction (DR) method as an efficient technique for reliability analysis can acquire its increased efficiency when it is applied to highly nonlinear problems. In the highly nonlinear engineering systems, 4N+1 (N: number of random variables) sampling is generally recognized to be appropriate. However, there exists uncertainty concerning the standard for judgment of non-linearity of the system as well as possibility of diverse degrees of non-linearity according to each of the random variables. In this regard, this study judged the linearity individually on each random variable after 2N+1 sampling. If high non-linearity appeared, 2 additional sampling was administered on each random variable to apply the DR method. The applications of the proposed sampling to the examples produced the constant results with increased efficiency.

Dynamic Characteristic Analysis of CNC Grinding Center (High-speed CNC Grinding Center구조의 동적거동 해석)

  • 박종권;노승국;성활경
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • /
    • pp.648-652
    • /
    • 1996
  • Grinding Center(GC)는 머시닝센터가 갖는 드릴링, 태핑 등의 절삭가공의 수행은 물론 주축의 고속화, 이송계의 고정밀화를 토대로 연삭숫돌의 절삭성 회복과 다듬질면의 거칠기를 확보하기 위한 기계로서 Dressing/Truing장치, 기상계측 장치, CNC기능을 구비하여 테이블과 공구간에 3차원의 상대운동을 시킴으로써 평면연삭, 내면연삭, 홈연삭, 캠연삭 등의 복잡한 형상의 연삭가공에 대해서도 공정을 집약화 할 수 있는 기계이다.(중략)

  • PDF