• Title, Summary, Keyword: 변위

Search Result 6,090, Processing Time 0.046 seconds

Study on Behavior of Pile Foundation in Soft Soils (연약지반상 기초말뚝의 거동 연구)

  • Kim Dae-Kyu
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.6 no.5
    • /
    • pp.428-431
    • /
    • 2005
  • In this paper, the displacement and stress of pile foundation constructed in the soft cohesive soils were measured and investigated at each construction phase. The piles belongs to compressive stress then extension due to lateral flow of soft soils. Battered piles showed different stress state according to construction direction. The lateral displacements of piles radically occurred at the embankment phase.

  • PDF

Influence of Weak Ground Ahead of the Tunnel Face on 3D-displacement and Face Extrusion (막장전방의 연약층이 터널 3차원변위 및 막장 수평변위에 미치는 영향)

  • Jeon, Je-Sung
    • Journal of the Korean Geotechnical Society
    • /
    • v.19 no.6
    • /
    • pp.189-206
    • /
    • 2003
  • During tunnel excavation in urban area a systematic monitoring is important for the purpose of determination of support type and quantity, as well as for the control of stability of both surface structures and the tunnel itself due to the frequently, and in many cases, abruptly changing ground condition. In Austria absolute displacement monitoring methods have replaced relative displacement measurements by geodetic methods to a large extent. Prompt detection of weak ground ahead of the tunnel face as well as better adjustment of excavation and support to the geotechnical conditions is possible with the help of the improved methods of data evaluation on sites. Deformation response of the ground to excavation starts ahead of the tunnel face, therefore, the deformation and state of the tunnel advance core is the key factor of the whole deformation process after excavation. In other words, the rigidity and state of the advance core play a determining role in the stability of both surface structures and the tunnel itself. This paper presents the results from detailed three-dimensional numerical studies, exploring vertical displacements, vector orientations and extrusions on tunnel face during the progressive advancement for the shallow tunnel in various geotechnical conditions.

Prototype Phase Array Antenna using Ferroelectric Phase Shifter (강유전체 위상변위기를 이용한 위상배열 안테나)

  • Moon, Seung-Eon;Ryu, Han-Cheol;Kwak, Min-Hwan;Kim, Young-Tae;Lee, Sang-Seok;Lee, Su-Jae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • /
    • pp.127-130
    • /
    • 2003
  • 4-bit 강유전체 위상변위기를 이용하여 10 GHz, 상온에서 작동하는 위상배열 안테나를 설계 및 제작하였다. 이 안테나는 빔 스캔을 위하여 전압에 대한 비선형특성을 보이는 강유전체 Bal-xSrxTiO3 (BST)를 기본으로 하는 위상변위기를 이용하였다. 우리는 펄스레이져 증착법으로 MgO (001) 기판위에 걸맞게 증착된 BST 박막을 일반적인 사진공정과 식각법을 이용하여 동일평판형 전극을 가진 위상변위기를 만들었다. 일반적인 동일평판형 강유전체 위상변위기의 경우 연결 전송선로의 임피던스와의 차이로 인해 반사손실과 이로 인한 부가적인 삽입손실이 발생한다. 이런 손실들을 줄이기 위해 입력과 출력 포트에 임피던스 매칭을 하였다. 이렇게 테이퍼링되어 만들어진 동일평판형 위상변위기는 이전의 구조에 비해 반사 손실과 삽입 손실 값에서 각각 약 10, 2 dB 정도씩의 개선을 보였다. 이 구조로 전송선로의 길이를 길게하여 만든 1-bit 강유전체 위상변위기는 10 GHz, 150 V의 전압변화에서 180도의 차등위상변위를 보였으며 최대 삽입손실과 최대 반사손실은 각각 약 10 dB, 20 dB 이다. 안테나 모듈은 4개의 마이크로스트림 패치 안테나와 4개의 강유전체 위상변위기로 이루어졌는데 10 GHz, 150 V의 전압변화에서 약 15도의 빔 스캔을 확인하였다.

  • PDF

Quantitative Analysis of 3-D Displacements Measurement by Using Holospeckle Interferometry (홀로스펙클 간섭법을 이용한 3차원 변위측정의 정량적 연구)

  • 주진원;권영하;박승옥
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.17 no.5
    • /
    • pp.1208-1217
    • /
    • 1993
  • The simple and effective optical technique synthesizing holographic interferometry and speckle photography is presented. The optical system used in this experiment is based on image holography. A cantilever beam located on the precision translator is used to evaluate this measurement system. Experimental results agree well with the actual displacements within the error of 2.8%. As an its application, three dimensional contact deformation in the ball indentation is measured by using this optical system and compared with the numerical analysis by finite element method.

Displacement Prediction of Swept Composite Cantilevered Panel Wings Using Strains (변형률을 이용한 복합재 평판 후퇴익 구조물의 변위 예측)

  • Kim, Mun-Guk;You, Je-Gyun;Kim, So-Young;Kim, In-Gul;Kim, Geun-Sang;Jeon, Min-Hyeok
    • Composites Research
    • /
    • v.30 no.5
    • /
    • pp.280-287
    • /
    • 2017
  • The complex deformation of the swept composite wing occurs due to the torsional load and bending load during the flight. Therefore, prediction for displacement of swept composite wing is required for structural health monitoring. Wing displacements can be predicted by using relationship between displacements and strains. The strain distributions on the fixed-end are complex due to the geometric shape of the swept wing. Because of those strain distribution, the wing displacement can be diversely predicted by the strain sensing locations. In this paper, displacements prediction of swept composite wing was performed by considering complex strain distributions. The predicted displacements under various loading condition were consistent with those calculated by FEA and verified through the bending test.

Response Analysis of Nearby Structures to Excavation-Induced Advancing Ground Movements (지반굴착 유발 진행성 지반변위에 의한 인접구조물의 거동분석)

  • Son, Moorak
    • Journal of The Korean Society of Civil Engineers
    • /
    • v.29 no.4C
    • /
    • pp.153-162
    • /
    • 2009
  • This paper investigates the effects of excavation-induced ground movements on nearby structures, considering soil-structure interactions of different soil and structural characteristics. The response of four and two-story block structures, which are subjected to excavation-induced advancing ground movements, are investigated in different soil conditions using numerical analysis. The structures for numerical analysis are modelled to have cracks when the shear and tensile stress exceed the maximum shear and tensile strength. The response of four and two-story block structures are investigated with advancing ground movement phases and compared with the response of structures which are subjected to excavation-induced total ground movement. The response of structures is compared among others in terms of the magnitude and shape of deformations and cracks in structures for different structure and ground conditions. The results of the comparison provide a background for better understandings for controlling and minimizing building damage on nearby structures due to excavation-induced ground movements.

  • PDF

Accuracy Analysis of Close-Range Digital Photogrammetry for Measuring Displacement about Loading to Structure (하중에 따른 구조물 변위계측을 위한 근접수치사진측량의 정확도 분석)

  • Choi, Hyun;Ahn, Chang Hwan
    • Journal of The Korean Society of Civil Engineers
    • /
    • v.29 no.4D
    • /
    • pp.545-553
    • /
    • 2009
  • This paper describes the result of study on measurement of displacement of structure by means of non-contacting method, close-range digital photogrammetry using digital camera. To apply close-range digital photogrammetry to displacement measurement of structure, correction of lens distortion that interferes geometrical analysis has been carried out and then measuring displacement was performed on load regulated-rahmen. For enhanced applicability of displacement measurement, MIDAS which is a structural analysis program was used for modeling and the result was taken from comparative analysis. As a result of the study, it is showed that close-range digital photogrammetry could supplement several weaknesses of LVDT and cable displacement meter and, especially, economy in the perspective of measuring time could be realized. Close-range digital photogrammetry using digital camera can be applied to the area where requires visual analysis such as 3D modeling of structure, profile replication of measurement of structure as well as measurement of displacement of structure.

  • PDF

Seismic Performance Improved Design of Reinforced Concrete Columns Strengthened by Steel Jackets Using Displacement-based Design (스틸재킷 보강 철근콘크리트 기둥의 변위기반 내진 성능 개선 설계 방법)

  • Jung, In-Kju;Park, Moon-Ho;Cho, Chang-Geun
    • Journal of the Korea Concrete Institute
    • /
    • v.22 no.1
    • /
    • pp.11-18
    • /
    • 2010
  • In this study, a procedure of performance-based design for the seismic retrofit of reinforced concrete columns strengthened by steel jackets has been presented. In order to predict the target displacement of retrofitted columns, a nonlinear analysis of reinforced concrete columns retrofitted with steel jackets has been developed based on a segmental model with the fiber cross-sectional approach. The seismic displacement level of retrofitted columns is estimated both by the direct displacement-based design method and by the displacement coefficient method. In examples of seismic retrofitted columns, the current seismic retrofit procedure gives good results in improvements of displacement levels and displacement ductilities of retrofitted columns.

Applications of Displacement Response Estimation Algorithm Using Mode Decomposition Technique to Existing Bridges (모드분해기법을 이용한 변위응답추정 알고리즘의 실교량 적용)

  • Chang, Sung-Jin;Kim, Nam-Sik
    • Journal of The Korean Society of Civil Engineers
    • /
    • v.30 no.3A
    • /
    • pp.257-264
    • /
    • 2010
  • Generally, estimations on the displacement as an important factor in evaluating the safety of large structures could be a barometer assessing whether the condition of the structure is deteriorating. Practically, it is not easy how to measure the displacement response to large structures like suspension bridges. In this study, as a method for estimation displacement response from strain signals, mode decomposition technique is proposed. Total displacement response is estimated by superposing quasistatic displacement response and modal displacement responses in dominant modes with larger contributions after estimating the modal displacement responses. If foiled strain gauges are used to measure strain signals, there would likely to generate electric noise, what's more, the more measuring points there are the more economic burden it could be. In order to solve such problems, fiber optic bragg-grating(FBG) sensors were used, which have multi-point measurements with no effect on electric noises. Therefore, the experiment was performed through dynamic load test of suspension bridge and plate-girder bridge to review the possibility for using mode decomposition technique.

Lateral Drift Control of High-rise Buildings using Partial Reanalysis Algorithm (부분재해석 기법을 이용한 고층건물 횡변위제어)

  • Lee, Jae-Cheol;Kim, Chee-Kyeong
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.22 no.1
    • /
    • pp.81-88
    • /
    • 2009
  • This paper alined at the development of a lateral drift control method that is able to quantitatively control the lateral drift of global node. For this, we applied an efficient partial reanalysis algorithm. By using this algorithm, we could recalculate the displacement and member force of the specific node without reanalyzing the entire structure when member stiffness changes partially. The theoretical concepts of the algorithm are so simple that it is not necessary to solve the complicate differential equation or to repeat the analysis of entire structure. The proposed method calculates the drift contribution of each member for the global displacement according to the variation of section sizes by using the algorithm. Then by changing the member sizes as the order of drift contribution, we could control the lateral drift of global node with a minimum quantity of materials. 20 story braced frame structure system is presented to illustrate the usefulness of proposed method. It is shown that the proposed method is very effective in lateral drift control and the results obtained by proposed method are consistent with those of commercial analysis program.