• Title/Summary/Keyword: anchoring mechanism

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Study on stress transition mechanism by tensile and fracture characteristics of membrane material at bolting part in clamping part of membrane Structures (막구조 정착부의 볼트접합부 막재료의 신장 및 파단상태를 통한 응력전달체계에 관한 연구)

  • Kim, Hee-Kyun;Shim, Chun-Bo;Kim, Jae-Yeol
    • Journal of Korean Association for Spatial Structures
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    • v.23 no.4
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    • pp.97-105
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    • 2023
  • The membrane structure should maintain the membrane materials in tension for structural stability guaranty. The anchoring part in the membrane structure is an important part. It has the function to introduce tension into membrane materials and function to transmit stress which membrane materials receives to boundary structure such as steel frames. In this paper, it grasps anchoring system of the anchoring part in the membrane structure concerning the fracturing characteristic condition of membrane structure, and the influence which is caused to yield it designates the stress state when breaking the membrane structure which includes the anchoring part and that stress transition mechanism is elucidated as purpose. This paper follows to previous paper, does 1 axial tensile test concerning the bolting part specimen, grasp of fracturing progress of the bolting part and the edge rope and hardness of the rubber, does the appraisal in addition with the difference of bolt tightening torque. As a result, the influence which the bolt anchoring exerts on the fracturing characteristics of the membrane material in the membrane structure anchoring part is examined.

Two-dimensional Model Testing System for Analysis of PVD Installation and Soil Disturbance (PVD 설치 및 지반교란의 분석을 위한 2차원 모형실험 시스템)

  • Kim, Jae Hyun;Choo, Yun Wook;Park, Hyun-Il;Kim, Dong-Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.4C
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    • pp.149-157
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    • 2012
  • In order to investigate the soil disturbance induced by anchor-shoe for PVD installation and the anchoring mechanism, a new two dimensional testing system was developed. By using the developed testing system, 1g and centrifuge model tests were performed, simulating the driving-retrieval process of both conventional symmetric anchor shoe and new asymmetric anchor shoe. Various size anchor-shoes were simulated and the results were compared. The images recorded during the installation were analyzed by image processing technique. The results of the image analysis presented the clay disturbance depending on the size and type of anchor shoe. In addition, from the retrieval process, the anchoring mechanism was revealed and the holding capacity was measured. As results, the size of anchor shoe influences the soil disturbance and holding capacity. The new asymmetric anchor shoe reduces the soil disturbance and improves anchoring performance.

Investigating the supporting effect of rock bolts in varying anchoring methods in a tunnel

  • Wang, Hongtao;Li, Shucai;Wang, Qi;Wang, Dechao;Li, Weiteng;Liu, Ping;Li, Xiaojing;Chen, Yunjuan
    • Geomechanics and Engineering
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    • v.19 no.6
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    • pp.485-498
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    • 2019
  • Pre-tensioned rock bolts can be classified into fully anchored, lengthening anchored and point anchored bolts based on the bond length of the resin or cement mortar inside the borehole. Bolts in varying anchoring methods may significantly affect the supporting effect of surrounding rock around a tunnel. However, thus far, the theoretical basis of selecting a proper anchoring method has not been thoroughly investigated. Based on this problem, 16 schemes were designed while incorporating the effects of anchoring length, pretension, bolt length, and spacing, and a systematic numerical experiment was performed in this paper. The distribution characteristics of the stress field in the surrounding rock, which corresponded to various anchoring scenarios, were obtained. Furthermore, an analytical approach for computing the active and passive strengthening index of the anchored surrounding rock is presented. A new fully anchoring method with pretension and matching technology are also provided. Then, an isolated loading model of the anchored surrounding rock was constructed. The physical simulation test for the bearing capacity of the model was performed with three schemes. Finally, the strengthening mechanism of varying anchoring methods was validated. The research findings in this paper may provide theoretical guidelines for the design and construction of bolting support in tunnels.

Temperature profile in the laminar lifted flame (부상화염 내부의 온도분포)

  • An, Hee Sung;Lee, Byeong Jun;Park, Chul-Woung;Park, Seung-Nam
    • 한국연소학회:학술대회논문집
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    • 2014.11a
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    • pp.357-358
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    • 2014
  • Coherent anti-Stokes Raman spectroscopy is one of the best tools to measure temperature distributions in the flame. Since it does not disturb the flow field, it could be used to study anchoring mechanism especially in the lifted flame. However, the length of probe volume is, normally, much greater than flame thickness. This weak point was overcome with lens combination in this study. It was found out that no peculiar temperature changes was happened near tribrachial point and heat transfer to the upstream was minimal near the flame anchoring position.

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Mechanism Development and Position Control of Smart Buoy Robot

  • Park, Hwi-Geun;Kim, Hyun-Sik
    • Journal of Ocean Engineering and Technology
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    • v.35 no.4
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    • pp.305-312
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    • 2021
  • There is a gradual increase in the need for energy charging in marine environments because of energy limitations experienced by electric ships and marine robots. Buoys are considered potential energy charging systems, but there are several challenges, which include the need to maintain a fixed position and avoid hazards, dock with ships and robots in order to charge them, be robust to actions by birds, ships, and robots. To solve these problems, this study proposes a smart buoy robot that has multiple thrusters, multiple docking and charging parts, a bird spike, a radar reflector, a light, a camera, and an anchor, and its mechanism is developed. To verify the performance of the smart buoy robot, the position control under disturbance due to wave currents and functional tests such as docking, charging, lighting, and anchoring are performed. Experimental results show that the smart buoy robot can operate under disturbances and is functionally effective. Therefore, the smart buoy robot is suitable as an energy charging system and has potential in realistic applications.

Characteristics of Anchor Behavior Resisting Buoyancy Forces in the Weathered Rock (풍화암에 시공된 부력저항 앵커의 거동특성)

  • Yoo, Nam-Jae;Lee, Gun-Chag;Jeong, Gil-Soo;Park, Byung-Soo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.10a
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    • pp.698-705
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    • 2005
  • This study contains actual scaled site experiments on mediation factors affecting ultimate pulling force of the buoyancy resisting anchor which is installed underground water level suffering buoyancy force and breaking mechanism. Site buoyancy test selected the buoyancy acting site where acting buoyancy to the station structure since the stream and reservoir is neighboured to the vicinity ground and executed site experiments leading to variation of anchoring length, drilling diameter and tendon diameter at the weathered rock ground. The test result showed that pulling force getting increased more and more proportionate to increase of anchoring length, drilling diameter and tendon diameter, and as a result of analysis for correlations between anchoring length-ultimate limited load and drilling diameter-ultimate load (on the basis of 254mm settlement), modulus of correlation showed very high relation 0.9 and 0.99 respectively and correlation formular showed the limited load is increasing proportionate to cubic meters of anchoring length as well as the ultimate load proportionate to alignment of drilling diameter. It is also showed that limited load increased about 42.5% from 392kN to 559kN as a result of change the tendon diameter to 36mm and 50mm.

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Electro-Optical and Switching Behavior of In-plane Switching Twisted Nematic Liquid Crystal Display

  • Kimura, Munehiro
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.1092-1095
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    • 2003
  • A driving mechanism and excellent features for an in-plane switching twisted nematic liquid crystal mode (IT mode) that could possibly improve the viewing-angle and color shift characteristics and the cell gap error tolerance is proposed. .It is important that the surface azimuthal anchoring strength of the liquid crystal cell differs at the upper and lower substrates. Furthermore. as a rubbing-free LCD. amorphously aligned in-plane switching twisted nematic mode (a-IT mode) is also demonstrated.

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Liquid Crystal Alignment on Solid Substrates

  • Kim, Jae-Hoon;Shi, Yushan;Kumar, Satyendra
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.755-758
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    • 2005
  • The mechanism responsible for liquid crystal (LC) alignment on solid substrates treated with mechanical rubbing or polarized UV is not understood. The results of x-ray reflectivity study of LC alignment on a large number of different alignment layers show that the anisotropy in the surface roughness of the substrate completely determines the LC alignment. The anchoring energy depends on the degree of roughness anisotropy and chemical interactions between the substrate and LC molecules.

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Research on reinforcement mechanism of soft coal pillar anchor cable

  • Li, Ang;Ji, Bingnan;Zhou, Haifeng;Wang, Feng;Liu, Yingjie;Mu, Pengfei;Yang, Jian;Xu, Ganggang;Zhao, Chunhu
    • Geomechanics and Engineering
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    • v.29 no.6
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    • pp.697-706
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    • 2022
  • In order to explore the stable anchoring conditions of coal side under the mining disturbance of soft section coal pillar in Wangcun Coal Mine of Chenghe Mining Area, the distribution model of the anchoring support pressure at the coal pillar side was established, using the strain-softening characteristics of the coal to study the distribution law of anchoring coal side support pressure. The analytical solution for the reinforcement anchorage stress in the coal pillar side was derived with the inelastic state mechanical model. The results show that the deformation angle of the roadway side and roof increases with the roof subsidence due to the mining influence at the adjacent working face, the plastic deformation zone extends to the depth of the coal side, and the increase of anchorage stress can effectively control the roof subsidence and further deterioration of plastic zone. The roadway height and the peak support pressure have a certain influence on the anchorage stress, the required anchorage stress of the coal side rises with the roadway height and the peak support pressure. The required anchorage stress of the coal pillar side decreases as the cohesion between the coal seam and the roof and floor and the anchor length increases. Then, applied the research result to Wangcun coal mine in Chenghe mining area, the design of anchor cable reinforcement support was proposed for the section of coal pillars side that has been anchored and deformed, which achieved great results and effectively controlled the convergence and deformation of the side, providing a safety guarantee for the roadway excavation and mining.

Anchorage mechanism of inflatable steel pipe rockbolt depending on rock stiffness (팽창형 강관 록볼트의 암반 강성에 따른 정착 거동 특성)

  • Kim, Kyeong-Cheol;Kim, Ho-Jong;Jung, Young-Hoon;Shin, Jong-Ho
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.2
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    • pp.249-263
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    • 2017
  • The expansion behavior of inflatable steel pipe rockbolt shows geometric nonlinearity due to its ${\Omega}-shaped$ section. Previous studies on the anchoring behavior of inflatable steel pipe rockbolt were mainly performed using theoretical method. However, those studies oversimplified the actual behavior by assuming isotropic expansion of inflatable steel pipe rockbolt. In this study, the anchoring behavior of the inflatable steel pipe rockbolt were investigated by the numerical method considering the irregularity of pipe expansion and other influencing factors. The expansion of inflatable steel pipe rockbolt, the contact stress distribution and the change of the average contact stress and the contact area during installation were analyzed. The contact stresses were developed differently depending on the constitutive behavior of rocks. Small contact stresses occurred in steel pipes installed in elasto-plastic rock compared to steel pipes installed in elastic rock. Also, the anchoring behaviors of the inflatable steel pipe rockbolt were different according to the stiffness of the rock. The steel pipe was completely unfolded in the case of the stiffness smaller than 0.5 GPa, but it was not fully unfolded in the case of the stiffness larger than 0.5 GPa for the given analysis condition. When the steel pipe is completely unfolded, the contact stress increases as the rock stiffness increases. However, the contact stress decreases as the rock stiffness increases when the steel pipe is not fully expanded.