• Title/Summary/Keyword: 변형량

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The Determination of Required Tensile Strength of Geosynthetic Reinforcements for Embankment on Soft Ground (연약지반 보강성토에서 섬유보강재 소요인장강도의 결정)

  • 이광열;황재홍;구태곤
    • Journal of the Korean Geotechnical Society
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    • v.19 no.6
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    • pp.379-385
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    • 2003
  • In the existing method to design geosynthetic reinforced embankment, the required strength of reinforcements is determined by vertical stress only rather than strain. This strength is not in accord with tensile strength that behaves as reinforcement in earth structures. The reinforcement and adjacent soil on the failure plan behave in one unit at the initial stress phase but they make a gap in strain as stress increases. This issue may cause a big impact as a critical factor on geosynthetic reinforcement design in earth structures. The quantitative analysis on strain behavior was performed with a PET Mat reinforced embankment on soft ground. From this study, several outstanding discussions are found that tensile strength of reinforcement governs the failure of embankment when the soil stress is greater than failure stress. Also the optimum required tensile strength of geosynthetic reinforcement(Tos) should be determined by stress, displacement, displacement gap and safety factor of soil-PET Mat at the location of PET Mat.

Tapered Joint Design for Power Transmission of MW-grade Wind Turbine (MW급 풍력발전기 동력전달용 테이퍼 연결장치 설계에 관한 연구)

  • Kang, JongHun;Bae, JunWoo;On, Hanyong;Kwon, Yongchul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.11
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    • pp.1183-1189
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    • 2015
  • This study focuses on the design of the tapered joints of a wind power turbine. The main variables of the tapered joint are the transmitted torque, shaft diameter, contact area of the tapered ring, and tightening torque of the bolts, which applies a compressive pressure from the hub to the shaft. The stress distribution of the taper fit was calculated under axisymmetric plane strain conditions because of the small taper angle. The axial displacement of the clamp can be calculated from the radial elastic deformation and the taper angle. The stress field of each ring is obtained from the cylinder stress equation. To verify the accuracy of the calculation, finite element (FE) analysis was performed, and the results of the calculation and FE analysis were compared. The hoop stress of the tapered surface showed a discrepancy of approximately 10, but the trends of the stress distributions of each component and the relative movement obtained by FE analysis were in good agreement with the analytical calculation results.

Effects of 3-D Fracture Tensor Parameters on Deformability of Fractured Rock Masses (삼차원 절리텐서 파라미터가 절리성 암반의 변형특성에 미치는 영향)

  • Ryu, Seongjin;Um, Jeong-Gi
    • Tunnel and Underground Space
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    • v.31 no.1
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    • pp.66-81
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    • 2021
  • The effects of directional fracture tensor components and first invariant of fracture tensor on deformation moduli and shear moduli of fractured rock masses is analyzed based on regression analysis performed between 3-D fracture tensor parameters and deformability of DFN blocks. Using one or two deterministic joint sets, a total of 224 3-D discrete fracture network (DFN) cube blocks were generated with various configurations of deterministic density and probabilistic size distribution. The fracture tensor parameters were calculated for each generated DFN systems. Also, deformability moduli with respect to three perpendicular direction of the DFN cube blocks were estimated based on distinct element method. The larger the first invariant of fracture tensor, the smaller the values for the deformability moduli of the DFN blocks. These deformability properties present an asymptotic pattern above the certain threshold. It is found that power-law function describes the relationship between the directional deformability moduli and the corresponding fracture tensor components estimated in same direction.

A Consideration on Deformation Characteristics of Normally-Consolidated Clays by Various Stress Paths (다양한 응력경로에 따른 정규압밀 점성토의 변형특성 고찰)

  • 김창엽;정충기
    • Journal of the Korean Geotechnical Society
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    • v.15 no.1
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    • pp.161-173
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    • 1999
  • Settlement analysis based on oedometer test results with or without Skempton-Bjerrum's modification method ( widely used for practical purposes when estimating consolidation settlements of soft clay deposits) has shortcomings that it cannot simulate real stress states and deformation behaviors of soils in case that in-situ loading and deformation conditions are not 1-dimensional. In this study, the stress path method, reflecting various probable stress paths, was employed to normally - consolidated kaolinite samples by using automated triaxial testing device which can control stress paths automatically. From this experimental study, elastic, consolidation, secondary compression and pore pressure development - dissipation behaviors under various stress paths were analyzed and deformation characteristics of soft clays, which can be the basis of rational estimation of settlements, were studied. Also by comparing results of stress path tests with those of 1-dimensional consolidation tests, limitations and problems of conventional methods were clarified.

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Application of Statistical Analysis to Analyze the Spatial Distribution of Earthquake-induced Strain Data (지진유발 변형률 데이터의 분포 특성 분석을 위한 응용통계기법의 적용)

  • Kim, Bo-Ram;Chae, Byung-Gon;Kim, Yongje;Seo, Yong-Seok
    • The Journal of Engineering Geology
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    • v.23 no.4
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    • pp.353-361
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    • 2013
  • To analyze the distribution of earthquake-induced strain data in rock masses, statistical analysis was performed on four-directional strain data obtained from a ground movement monitoring system installed in Korea. Strain data related to the 2011 Tohoku-oki earthquake and two aftershocks of >M7.0 in 2011 were used in x-MR control chart analysis, a type of univariate statistical analysis that can detect an abnormal distribution. The analysis revealed different dispersion times for each measurement orientation. In a more comprehensive analysis, the strain data were re-evaluated using multivariate statistical analysis (MSA) considering correlations among the various data from the different measurement orientations. $T_2$ and Q-statistics, based on principal component analysis, were used to analyze the time-series strain data in real-time. The procedures were performed with 99.9%, 99.0%, and 95.0% control limits. It is possible to use the MSA data to successfully detect an abnormal distribution caused by earthquakes because the dispersion time using the 99.9% control limit is concurrent with or earlier than that from the x-MR analysis. In addition, the dispersion using the 99.0% and 95.0% control limits detected an abnormal distribution in advance. This finding indicates the potential use of MSA for recognizing abnormal distributions of strain data.

New Approach on Modified Triangular Interferometer (삼각 간섭계를 이용한 shearography)

  • Kim, Soo-Gil;Ko, Myung-Sook
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2004.05a
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    • pp.214-216
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    • 2004
  • 3차원 홀로그램의 생성에 이용되었던 변형 삼각간섭계를 이용한 비접촉진단 방법에 대하여 논하고자 한다. 변형 삼각간섭계를 이용한 비접촉진단은 측정대상물체의 간섭패턴을 구하고 이로부터 위상지도와 변형량을 계산함으로써 이루어질 수 있다. 본 논문에서는 변형 삼각간섭계를 이용한 간섭패턴 생성과 관련한 몇 가지 실험결과를 제시한다.

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A Basic Study on Non-Contact Testing Application of Modified Triangular Interferometer (변형 삼각간섭계의 비접촉 진단적용어 관한 기초연구)

  • Kim, Soo-Gil
    • Proceedings of the KIEE Conference
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    • 2003.07c
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    • pp.1976-1977
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    • 2003
  • 3차원 영상저장과 복원에 이용되어왔던 변형 삼각간섭계를 이용하여 비접촉진단에의 응용가능성을 연구한다. 변형 삼각간섭계를 이용하여 측정대상물체의 간섭패턴을 3-5개 구하고 이로부터 위상지도를 얻고 이로부터 변형량을 계산할 수 있다는 것을 이론적으로 제시한다.

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Body structure for the front impact of One-Box car (One-Box Car 충돌 대비 차체 구조)

  • 박규환
    • Journal of the korean Society of Automotive Engineers
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    • v.13 no.3
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    • pp.19-24
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    • 1991
  • 본 고에서는 자동차 안전대책중에서 One-box car의 전면충돌 안전대책에 대하여 개략적으로 소개하고자 한다. 1. 충돌기본식 1/2M$V^{2}$=F.S에서 에너지 흡수율이 frame의 변형 평균 하중과 차체 변형량에 좌우된다. 2. frame 형상은 굽힘형보다 압축형이 동일한 변형구간에서 월등한 충돌에너지를 흡수한다. 3. 압축형 frame의 에너지 흡수효과는 main-frame의 버팀강도가 e.a-frame의 변형 하중보다 강해야만 그 효과를 충분히 얻을 수 있다.

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P.C Beam의 피로파괴 거동해석

  • 안세희;고상훈;박종철;김두환
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • 1999.06a
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    • pp.181-186
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    • 1999
  • 반복하중에 따른 P.C 구조물의 장착장치로 사용되는 Wedge 형상에 따른 거동특성을 파악하기 위하여 정적최대하중을 이용하여 피로시험을 수행하였다. 또한 피로시험 결과로부터 반복회수에 따른 시험 체의 균열양상, 하중-변위, 하중-변형율, 하중-중앙 최대 변위, 하중-영구 변형량, 반복횟수에 따른 S-N선도 등을 고찰하였다. (중략)

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