• Title, Summary, Keyword: 빔-스프링 모델

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Three-Dimensional Finite Element Analysis of Tieback Walls in Sand

  • Lim, Yu-Jin;Briaud, Jean-Louis
    • Geotechnical Engineering
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    • v.13 no.3
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    • pp.33-52
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    • 1997
  • A three dimensional nonlinear finite element analysis is used to study the influence of various design decisions for tieback walls. The numerical model simulates the soldier piles and the tendon bonded length of the anchors with beam elements, the unbonded tendon with a spring element, the wood lagging with the shell elements, and the soil with solid 3D nonlinear elements. The soil model used is a modified hyperbolic model with unloading hysteresis. The complete sequence of construction is simulated including the excavation, and the placement and stressing of the anchors. The numerical model is calibrated against a full scale instrumented tieback wall at the National Geotechnical Experimentation Site (NGES) on the Riverside Campus of Texas A&M University. Then a parametric study is conducted. The results give information on the influence of the following factors on the wall behavior : location of the first anchor, length of the tendon unbonded zone, magnitude of the anchor forces, embedment of the soldier piles, stiffness of the wood lagging, and of the piles. The implications in design are discussed.

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The development of a back analysis program for subsea tunnel stability under operation: longitudinal direction (운영 중 해저 터널의 안정성 평가를 위한 역해석 프로그램 개발: 종단방향)

  • An, Joon-Sang;Kim, Byung-Chan;Moon, Hyun-Koo;Song, Ki-Il
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.6
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    • pp.545-556
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    • 2016
  • If a back analysis is used in various measurement information for the estimation of an operating subsea tunnel safety, it is possible to obtain the results within efficient error rate. With such a commercial geotechnical analysis program as FLAC3D, back analysis is performed with a DEA which was validated in previous studies. However, there is a problem that is relatively a time-consuming analysis. For this reason, beam-spring model-based FEM solver which takes shorter relative analysis time, was developed by Python language, and then combined with the built-DEA. In order to consider the assessment of safety of an operation tunnel near real-time, a program for longitudinal direction tunnel was developed due to its relative easy development for analysis solver engine.

Development of a tool to automate finite element analysis of a spindle system of machine tools (공작기계 주축 시스템의 유한요소해석 자동화를 위한 툴 개발)

  • Choi, Jin-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.4
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    • pp.2350-2355
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    • 2015
  • A tool was developed in this research for automation of one-dimensional finite element analysis (1D FEA) for design of a machine tool spindle system composed mainly of a shaft and bearings. As it is based on object-oriented programing, it uses the objects of a CAD system. It requires minimum data to be input to define the spindle system such as shaft cross-sections and bearing stiffness. Then, it automatically generates the geometric model based on the data and then, converts it into the FE model of 1D beams and springs. The graphic user interfaces developed allow a user to interact with the tool. This tool can be applied to identification of a near optimal design of the spindle system in minimum time and efforts by automating the FEA process with numerous design changes.

The development of a back analysis program for subsea tunnel stability under operation: transversal tunnel section (운영 중 해저 터널의 안정성 평가를 위한 역해석 프로그램 개발: 횡단방향)

  • An, Joon-Sang;Kim, Byung-Chan;Lee, Sang-Hyun;Song, Ki-Il
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.2
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    • pp.195-212
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    • 2017
  • When back analysis is used for the assessment of an operating subsea tunnel safety in various measurement information such as stress, water pressure and tunnel lining and ground stiffness degradation, the reliable results within tolerable error rate can be obtained. By utilizing a commercial geotechnical analysis program FLAC3D, back analysis can be performed with a DEA which has already been successfully validated in previous studies. However, relative more time-consumption is the drawback of this approach. For this reason, this study introduced beam-spring model-based on FEM solver which uses less analysis time relatively. Beam-spring program capable of structural analysis of a circular tunnel section was developed by using Python language and combined with the built-DEA. From the measurement datum, expected to estimate the stability of an operation tunnel close to real-time.

Flexible Multibody Dynamic Analysis of the Deployable Composite Reflector Antenna (전개형 복합재 반사판 안테나의 유연 다물체 동역학 해석)

  • Lim, Yoon-Ji;Oh, Young-Eun;Roh, Jin-Ho;Lee, Soo-Yong;Jung, Hwa-Young;Lee, Jae-Eun;Kang, Deok-Soo;Yun, Ji-Hyeon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.10
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    • pp.705-711
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    • 2019
  • Dynamic behaviors of the deployable composite reflector antenna are numerically and experimentally investigated. Equations of the motion are formalized using Kane's equation by considering multibody systems with two degrees of freedom such as folding and twisting angles. To interpret structural deformations of the reflector antenna, the composite reflector is modeled using a beam model with the FSDT(First-order Shear Deformation Theory). To determine design parameters such as a torsional spring stiffness and a damping coefficient depending on deployment duration, an inverted pendulum model is simply applied. Based on the determined parameters, dynamic characteristics of the deployable reflector are investigated. In addition, its results are verified and compared through deployment tests using a gravity compensation device.

Modelling and Analysis of Roll-Type Steel Mats for Rapid Stabilization of Permafrost (I) - Modeling - (영구동토 급속안정화를 위한 롤타입강재매트의 모델링과 해석(I) - 해석모델의 수립 -)

  • Moon, Do Young;Kang, Jae Mo;Lee, Janggeun;Lee, Sang Yoon;Zi, Goangseuo
    • Journal of the Korean Geosynthetics Society
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    • v.13 no.4
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    • pp.97-107
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    • 2014
  • Finite element modelling and analysis were conducted for the roll-type steel mats which were placed on loose sand and subjected to a standard truck wheel load in this study. The roll-type steel mats mean that the steel mats can be folded as a circle shape for the carrying to fields in cold regions where workability is limited and are developed for a rapid rehabilitation method for roadway across soft ground which is caused by thawing during the summer season in cold regions. The model is composed of link elements to simulate nonlinear behavior of connections between steel mats, thick shell elements to have flexural stiffness of the steel mats, and springs to simulate characteristics of foundation soils. The structural behaviors of the shell, link elements, and springs were verified at each modelling step through experiment and analysis. Beam and shell analysis without the link elements were conducted and compared to results obtained from the model presented in this study. Significant vertical displacement is shown in the shell model with hinge connections. Therefore, the results demonstrate that the analysis model for the roll-type steel mats on loose sand needs further detail parametric studies.