• Title/Summary/Keyword: Ring shield

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Nonlinear simulation of tunnel linings with a simplified numerical modelling

  • Zhao, Huiling;Liu, Xian;Bao, Yihai;Yuan, Yong
    • Structural Engineering and Mechanics
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    • v.61 no.5
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    • pp.593-603
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    • 2017
  • A high-efficiency simplified modelling approach is proposed for investigating the nonlinear responses of reinforced concrete linings of shield tunnels. Material and geometric nonlinearities are considered in the analysis of the lining structures undergoing large deformation before ultimately losing the load-carrying capacity. A beam-spring element model is developed to capture the force-transfer mechanism between lining segments and radial joints. The developed model is validated by comparing analyzed results to experimental results of a single-ring lining structure under two loading conditions: the ground overloading and the lateral unloading respectively. The results show that the lining structure under the lateral unloading due to excavation on the both sides of the tunnel is more vulnerable compared to the case of ground overloading on the top of the tunnel. A parameter study is conducted and results indicate that the lateral pressure coefficient has the greatest influence on the behaviour of the lining structure.

An Approach to the Design Parameter of Air-Cored Superconducting Synchronous Generator (공심형 초전도 동기발전기의 설계변수에 대한 연구)

  • Jo, Young-Sik;Hong, Jung-Pyo;Lee, Ju;Sohn, Myung-Hwan;Kwon, Young-Kil;Ryu, Kang-Sik
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.50 no.3
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    • pp.101-106
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    • 2001
  • Air-cored superconducting synchronous generator(ASSG) is characterized by an air-cored machine with its rotor iron and stator iron teeth removed. For this reason, in the case of the shape optimum design of ASSG, other design variables different from an iron-cored machine should be considered, which will lead to substantial improvement on the performance. The major design variables that are considered by using Three-dimensional Finite element Method(3D FEM) in this paper are : 1) field coil width, 2) axial length of magnetic shield, and 3) armature winding method. End-ring of armature winding is considered in the calculation of EMF. When it comes to field coil width, as field coil width enlarges, its effective field increases but the maximum field on the superconductor decreases. this determines the critical current density. this study presents an effective field coil width, axial length of magnetic shield, and armature winding method, and also the analysis is verified by the experimental results.

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Improvement of the Partial Discharges Phenomenon according to change of Conductor and Shield ring on the 38kV VCB Bushing (38kV VCB 부싱의 도체 및 쉴드링 변경에 따른 부분방전현상 개선)

  • Cha, Young-Kwang;Park, Soo-Min;Kang, Moo-Sung
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.1204-1205
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    • 2015
  • 본 연구는 38kV급 VCB의 외함에 체결된 부싱의 부분방전 발생 문제를 해결하기 위하여 부싱의 형상에 따른 부분방전 현상을 분석하였다. 부싱에 발생하는 부분방전의 패턴을 분석한 결과 도체나 외함 끝단 등 날카로운 부위에서 발생할 수 있는 코로나 방전 형태로 나타났다. 이를 해결하기 위해 도체와 쉴드링의 형상을 변수로 두고 실험을 진행하였으며 시작품 제작 전 비용과 시간을 최소화하기 위해 Maxwell 2D 프로그램으로 전계해석을 선진행한 뒤 설계에 반영하여 실험하였다. 실험 결과 쉴드링의 크기나 형상보다는 고전압부와의 거리가 부분방전의 크기에 더 큰 영향을 미친다는 것을 알 수 있었고, 도체의 두께를 변화시켰을 때의 부분방전 및 전계집중 변화폭이 가장 컸다.

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A Study on Shield ring Design for Relieved Electric Field Intensity in GIS Spacer Triple Junction (GIS 스페이서 삼중점 전계 완화를 위한 쉴드링 설계에 관한 연구)

  • Kwon, Gumin;Lee, Seungkwan;Kang, Mincheol;Jeong, Kyengsik;Kim, Kyonghoe
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.1181-1182
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    • 2015
  • 본 논문에서는 초고압 가스절연개폐장치(GIS, Gas Insulated Switchgear) 내 고체 절연물인 스페이서에서 삼중점의 전계를 완화하기 위한 쉴드링 설계 방법과 그에 따른 효과를 분석하였다. 이를 위해 420kV GIS 스페이서를 축대칭 모델로 단순화하여 전계해석을 수행하였으며, 쉴드링 직경에 따른 삼중점 전계세기 변화를 확인하였다. 또한 쉴드링과 스페이서 계면 사이의 최소 이격거리를 계산하여 쉴드링의 최적 직경을 구하였다. 추가적으로, 새로운 설계 기법인 Double 쉴드링 기법을 소개하고 기존의 쉴드링이 하나인 경우와 비교 분석하여 그 효과를 확인하였다.

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Petrologic Evolution of the Songaksan Monogenetic Volcano, Jeju Island, Korea (제주도 송악산 단성화산의 암석학적 진화)

  • 황상구;원종관;이문원;윤성효;이인우;김성규
    • The Journal of the Petrological Society of Korea
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    • v.10 no.1
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    • pp.13-26
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    • 2001
  • Songaksan volcano, which occurs as a monogenetic volcano on the southwestern promontory of Hallasan shield volcano, is composed of tuff ring, cinder cone, lava pond and cinder conelet complex on wide basalt plateau. Except for an influx of external quartz xenocrysts in the tuff ring. Totally the volcano ranges from trachyandesite to trachybasalt in petrography and chemical compositions, which confirm the continuum between the evolved and primitive compositions widely occurring in the Jeju volcanic system. Chemical data for the volcano show quantitative compositional variation from the lower to the upper part of the volcanic sequences. The continuous compositional variations generally define a compositionally zoned magma storage. The chemical data suggest that the compositiona1 donations might have resulted from the fractional crystallization of a parental alkali magma. As result, the Songaksan volcano initially tapped the lop of the zoned magma storage and subsequently erupted successively more primitive magma.

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Development of a Energy-saving LED module Using K-band Microwave Motion Detecting Sensor (K대역 마이크로파 움직임 감지 센서를 이용한 에너지 절감형 LED 모듈 개발)

  • Kim, Howoon;Woo, Dong Sik
    • Journal of IKEEE
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    • v.24 no.2
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    • pp.446-452
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    • 2020
  • In this paper, we propose a energy-saving LED module using K-band microwave motion detecting sensor. To oscillate K-band microwave signal, An oscillator using a hairpin-type microstrip resonator was designed to increase stability and make fabrication easier. To radiate the microwave signal, a two-channel(TX/RX) patch antenna arrays was developed. Wilkinson power divider and ring hybrid mixer were developed and applied to obtain Doppler shift from the received signal. Shield cans were installed to protect the stability of the signals and unwanted external noise. The proposed motion detection sensor was mounted on a demonstration LED module and the energy saving performance through pre-test was verified.

Three-Dimensional Insulation Design Algorithm Using NURB Surface and Its Application (NURB곡면을 이용한 3차원 절연설계 알고리즘과 그 응용)

  • Lee, B.Y.;Myung, S.H.;Han, I.S.;Park, J.K.;Kim, E.S.;Min, S.W.;Shin, Y.J.
    • Proceedings of the KIEE Conference
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    • 1997.07e
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    • pp.1684-1687
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    • 1997
  • In this paper, a three-dimensional algorithm for the insulation design of the high-voltage equipment is presented. In general, the insulation design consists of two steps. They are electric field calculation and correction of the shape to be designed. In the proposed algorithm, the combination method of charge simulation and surface charge simulation is used to calculate the three-dimensional electric fields. As for the correction of the shape, indirect control provided by rational B-spline is more useful than direct control. The use of rational B-spline reduces in the number of design variables and garrantees the smooth curvature of the designed shape. The proposed algorithm is applied to the design of the shape of the shield ring which has been designed by the method of trial and error.

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Forward probing utilizing electrical resistivity and induced polarization for predicting soil and core-stoned ground ahead of TBM tunnel face (전기비저항과 유도분극을 활용한 TBM 터널 굴착면 전방 토사지반 및 핵석지반 예측 기법)

  • Kang, Daehun;Lee, In-Mo;Jung, Jee-Hee;Kim, Dohyung
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.3
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    • pp.323-345
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    • 2019
  • It is essential to predict ground conditions ahead of a tunnel face in order to successfully excavate tunnels using a shield TBM. This study proposes a forward prediction method for a mixed soil ground and/or a ground containing core stones by using electrical resistivity and induced polarization exploration. Soil conditioning in EPB shield TBM is dependent upon the composition of mixed soils; a special care need to be taken when excavating the core-stoned soil ground using TBM. The resistivity and chargeability are assumed to be measured with four electrodes at the tunnel face, whenever the excavation is stopped to assemble one ring of a segment lining. Firstly, the mixed ground consisting of weathered granite soil, sand, and clay was modeled in laboratory-scale experiments. Experimental results show that the measured electrical resistivity considerably coincides with the analytical solution. On the other hand, the induced polarization has either same or opposite trend with the measured resistivity depending on the mixed ground conditions. Based on these experimental results, a method to predict the mixed soil ground that can be used during TBM tunnel driving is suggested. Secondly, tunnel excavation from a homogeneous ground to a ground containing core stones was modeled in laboratory scale; the irregularity of the core stones contained in the soil layer was modeled through random number generation scheme. Experimental results show that as the TBM approaches the ground that contains core stones, the electrical resistivity increases and the induced polarization fluctuates.

Deformation of segment lining and behavior characteristics of inner steel lining under external loads (외부 하중에 따른 세그먼트 라이닝 변형과 보강용 내부 강재 라이닝의 거동 특성)

  • Gyeong-Ju Yi;Ki-Il Song
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.26 no.3
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    • pp.255-280
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    • 2024
  • If there are concerns about the stability of segment lining due to section deficiency or large deformation in shield TBM tunnel, reinforcement can be done through ground grouting outside the tunnel or by using steel plate reinforcement, ring beam reinforcement, or inner double layer lining inside the tunnel. Traditional analyses of shield TBM tunnels have been conducted using a continuum method that does not consider the segmented nature of segment lining. This study investigates the reinforcement mechanism for double layer reinforced sections with internal steel linings. By improving the modeling of segment lining, this study applies Break-joint mode (BJM), which considers the segmented characteristics of segment lining, to analyze the deformation characteristics of double layer reinforced sections. The results indicate that the existing concrete segment lining functioned similarly to ground reinforcement around the tunnel, rather than distribution the load. In general, both the BJM model considering the segmentation of segment lining and the continuum rigid method were similar deformation shapes and stress distributions of the lining under load. However, in terms of deformation, when the load strength exceeded the threshold, the deformation patterns of the two models differed.

A Study on the Costume of the Gods in the Ancient Roman Myths (고대 로마 신화에 등장한 신들의 복식 연구)

  • 임상임;추미경
    • Journal of the Korean Society of Clothing and Textiles
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    • v.25 no.5
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    • pp.945-956
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    • 2001
  • The costume for gods in the Ancient Roman myth was studied by examining in the embossed-carving, sculptures, mural-painting and various documents of the period. The clothes item, hairstyle, symbol & ornaments and shoes of the gods in the Roman myths were analyzed to understand the formative process in the religious costumes, and results are as follows. First, the costumes for male gods are the same as those for ordinary men lived in ages, including toga, paludamentum, tebenna, tunica. The costumes for female gods are also the same as those for ordinary women lived in ages, including stola, palla, tunica. Second, the hairstyle of male gods is short curled-hair, twisty roll-up hair and braid long-hair due to the influence of Etrurian in the early days. Another hairstyle is appeared in form of the laurelled-crown. The hairstyle of female gods is curled long-hair, chignon style and braid roll-up hair decorated with hairband. Third, the symbol & ornaments which represent the responsible possession of male gods, are appeared in beard, a stick of the message, arrow-case, offering-dish, antlered-glass, shield, spear-handle, as the superhuman forms, such as the lightning shape. For female gods they are is appeared plastron, a stick of the message, flower. some female gods wear necklace, foot-ring, bracelet. Fourth, male gods wear shoes in forms of sandal, buskin, boots, but all female gods are in barefoot. It could be explained by the fact that a man-centered society in the ancient roman is reflected in the world of gods. As mentioned, Gods costume in Roman myths was very similar to or nothing different from the ordinary peoples in Rome. However, they used corps, sacrifices or sepcific symbols depending on the fields that they were responsible for in order to be distinguished from the ordinary people. This is the result from the peoples expression that they should keep a close relationship with Gods hoping to be protected, and rely on them under whatever circumstances.

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