• Title/Summary/Keyword: cable dynamics

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Dynamics modeling of a semi-submersible autonomous underwater vehicle with a towfish towed by a cable

  • Park, Jinmo;Kim, Nakwan
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.7 no.2
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    • pp.409-425
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    • 2015
  • In this paper, we employ a dynamics modeling method for investigating a multi-body dynamics system of semi-submersible autonomous underwater vehicles consisting of a towing vehicle operated near the water surface, a tow cable, and a towfish. The towfish, which is towed by a marine cable for the purposes of exploration or mine hunting, is modeled with a Six-Degree-of-Freedom (6-DOF) equation of motion that reflects its hydrodynamics characteristics. The towing cable, which can experience large displacements and deformations, is modeled using an absolute nodal coordinate formulation. To reflect the hydrodynamic characteristics of the cable during motion, the hydrodynamic force due to added mass and the drag force are imposed. To verify the completeness of the modeling, a few simple numerical simulations were conducted, and the results confirm the physical plausibility of the model.

Vibrational Characteristics on the Cables in Cable Stayed Bridge (사장교 케이블의 진동거동 특성)

  • Sung, Ikhyun
    • Journal of the Society of Disaster Information
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    • v.13 no.2
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    • pp.249-257
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    • 2017
  • Recently, a cable disconnection accident occurred due to a lightning strike at the Seohae Bridge located in Dangjin-Pyeongtaek City. This is a natural occurrence, but it is a recall that it is very important to review the safety issues due to the disconnection of cable bridges. In other words, the role of cables in cable bridges has a profound effect on the safety of the structure, and it has become necessary to grasp the effect on the entire structural system. The cable bridge is an economic bridge that builds the main tower and supports the bottom plate by cable. The influence of the cable is the main member, which is a big influence on the safety of the whole bridge system. In the cable-stayed bridge, the cables exhibit nonlinear behavior because of the change in sag, due to the dead weight of the cable, which occurs with changing tension in the cable resulting from the movement of the end points of the cable as the bridge is loaded. Modal analysis is conducted using the deformed dead-load tangent stiffness matrix. A new concept was presented by using divided a cable into several elements in order to study the effect of the cable vibration (both in-plane and swinging) on the overall bridge dynamics. The result of this study demonstrates the importance of cable vibration on the overall bridge dynamics.

Dynamic Response of 3-D Cable-Stayed Bridge Considering the Sway Vibrational Effect of Stays (케이블 횡진동을 고려한 3차원 사장교의 동적거동)

  • 성익현
    • Journal of the Korean Society for Railway
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    • v.2 no.3
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    • pp.36-45
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    • 1999
  • The basic idea of cable-stayed girder bridges is the utilization of high strength cables to provide intermediate supports for the bridge girder so that the girder can span a much longer distance. In the cable-stayed bridge, the cables exhibit nonlinear behavior because of the change in sag, due to the dead weight of the cable, which occurs with changing tension in the cable resulting from the movement of the end points of the cable as the bridge is loaded. Techniques required for the static analysis of cable-stayed bridges has been developed by many researchers. However, little work has been done on the dynamic analysis of such structures. To investigate the characteristics of the dynamic response of long-span cable-stayed bridges due to various dynamic loadings likes moving traffic loads. two different 3-D cable-stayed bridge models are considered in this study. Two models are exactly the same in structural configurations but different in finite element discretization. Modal analysis is conducted using the deformed dead-load tangent stiffness matrix. A new concept was presented by using divided a cable into several elements in order to study the effect of the cable vibration (both in-plane and swinging) on the overall bridge dynamics. The result of this study demonstrates the importance of cable vibration on the overall bridge dynamics.

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Dynamics model of the float-type wave energy converter considering tension force of the float cable

  • Hadano, Kesayoshi;Lee, Sung-Bum;Moon, Byung-Young
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.2
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    • pp.217-224
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    • 2014
  • We have developed the novel device that can extract energy from ocean waves utilizing the heaving motion of a floating mass. The major components of the energy converter are: a floater, a counterweight, a cable, a driving pulley, two idler pulleys, a ratchet, and a generator. The device generates power through the tension force in the cable and the weight difference between the floater and the counterweight. When the system is at static free condition, the tension in the cable is equal to the weight of the counterweight which is minimum. Therefore it is desirable to keep the counterweight lighter than the floater. However, experiments show that during the rise of the water level, the torque generated by weight of the counterweight is insufficient to rotate the driving pulley which causes the cable on the floater side to slack. The proposed application of the tension pulley rectifies these problems by preventing the cable from becoming slack when the water level rises. In this paper, the dynamics model is modified to incorporate the dynamics of the tension pulley. This has been achieved by first writing the dynamical equations for the tension pulley and the energy converter separately and combining them later. This paper investigates numerically the effect of the tension pulley on various physical quantities such as the cable tension, the floater displacement, and the floater velocity. Results obtained indicate that this application is successful in suppressing large fluctuations of the cable tension.

The Role of Abp140p in Actin Dynamics of Budding Yeast

  • Lim, Bum-Soon;Lee, Yong-Keun;Pon, Liza A.;Yang, Hyeong-Cheol
    • International Journal of Oral Biology
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    • v.30 no.1
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    • pp.17-22
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    • 2005
  • In the previous studies of Saccharomyces cerevisiae, Abp140p (actin binding protein 140) fused to GFP has been only a protein that can label actin cables of yeast cells so far. However, the role of Abp140p in actin dynamics was remained elusive. In this study, the function of Abp140p was investigated with a deletion mutant and overexpression of GFP fused Abp140p. The deletion mutant was slightly more susceptible to Latrunculin-A (Lat-A), an actin-monomer sequestering agent, than wild type, although no significant deformation of actin structures was caused by ABP 140 deletion. Overexpression of Abp140p-GFP retarded cell growth, and produced thick and robust actin cables. Lat-A was not able to destabilize the thick actin cables, which suggests that actin dynamics was compromised in the cells with surplus of Abp140p. Therefore, Abp140p seems to stabilize actin cables together with other bundling proteins. Recently, actin cable dynamics of budding yeast was found to have a resemblance to that of filopodial tip of cultured mammalian cells. Retrograde movement of actin cables from buds to mother cells indicated local generation of the cable at bud sites. By using Abp140p-GFP, we traced the steps in the generation of a new actin cable after elimination of old cables by sodium azide. Before the appearance of a new actin cable, Abp140p-GFP concentrated in buds and disappeared, as mother cells became abundant in actin cables. Our observations provide a direct evidence of actin cable formation at buds of budding cells.

Prediction of Vortex-induced Vibration of the Cable-Stayed Bridge with Steel Composite Deck (강합성 단면을 가진 사장교의 와류진동 발생 예측)

  • Cho, Jae-Young;Cho, Young-Rae;Lee, Hak-Eun
    • 한국방재학회:학술대회논문집
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    • 2007.02a
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    • pp.449-453
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    • 2007
  • After over a century of effort by researchers and engineers, the problem of bluff body flow, in particular vortex shedding frequency, remains almost entirely in the empirical, descriptive realm of knowledge. Computational methods have been systematically applied for vortex-induced vibrations of the cable-stayed bridge with steel composite deck by unsteady wind loadings due to vortex-shedding. The focus of this paper is to predict the vortex-induced vibration of the cable-stayed bridge with steel composite deck based computational fluid dynamics(CFD).

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A Nonlinear Analysis of Cable Stayed Bridge including Sway Vibrational Effects using Multiple Cable Elements (다수 케이블요소를 사용한 사장교의 횡방향진동을 포함한 비선형 해석)

  • Seong, Ik-Hyun;Yoon, Ki-Yong
    • Journal of Korean Society of Steel Construction
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    • v.12 no.6
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    • pp.661-670
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    • 2000
  • To investigate the characteristics of the dynamic response of long-span cable-stayed bridges due to various dynamic loadings likes moving traffic loads, two different 3-D cable-stayed bridge models are considered in this study. Two models are exactly the same in structural configurations but different in finite element discretization. Modal analysis is conducted using the deformed dead-load tangent stiffness matrix. A new concept was presented by using divided a cable into several elements in order to study the effect of the cable vibration (both in-plane and swinging) on the overall bridge dynamics. Futhermore case of asymmetric traffic loading clustered in one direction are also considered to study the torsional response of the bridge. The result of this study demonstrates the importance of cable vibration on the overall bridge dynamics.

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3D Nonlinear Fully Coupled Simulation of Cable and Tow-fish System (케이블-수중 예인체 시스템의 3차원 비선형 완전 연성해석)

  • Go, Gwangsoo;Lee, Euntaek;Ahn, Hyung Taek
    • Journal of Ocean Engineering and Technology
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    • v.30 no.6
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    • pp.458-467
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    • 2016
  • In this paper, a strongly coupled method for investigating the interaction between a cable and tow-fish is presented. The nodal position finite element method was utilized to analyze the nonlinear cable dynamics, and 6DOF equations of motion were employed to describe the 3D rigid body motion of the tow-fish. Combining cable and tow-fish systems into a single formulation allowed the two nonlinear systems to be strongly coupled into a unified nonlinear system. This strongly coupled system was numerically integrated in the time domain using a predictor/multi-corrector Newmark algorithm. To demonstrate the validity, efficacy, and applicability of the current approach, two different scenarios (virtual and sea trial) were simulated, and the simulation results were validated using the physical plausibility and the sea trial test.

A Study on the Expression Types of Cable Knitting (케이블 니팅의 표현 유형에 관한 연구)

  • Kim, Seongdal
    • Journal of Fashion Business
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    • v.22 no.5
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    • pp.41-51
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    • 2018
  • Cable knitting, one of the most representative structures of knitwear has been applied to a number of knit items in a variety of expressions every season. The purpose of this study is to analyze the various types of expressions applied with cable knitting techniques to make the necessary data for planning cable knit designs. The types of cable knitting were devide into two categories which are based on the cable knitting pattern and structure. Based on the pattern, firstly, formal type is a reproduction of traditional Aran knit style and is usually applied to a practical and comfortable timeless knit product. Secondly, informal type is irregular applied to patterns and directions to highlight the dynamics of cable patterns. Thirdly, contrasting type emphasizes the cable pattern by contrasting the color of the part of the cable pattern. Fourthly, figurative type is the expression of the conceptual motifs and using the cable knit pattern itself as motif. Based on the structure, firstly, open type is to emphasize patterns and spaces by utilizing open spaces created by the intersection of cabling stitches. Secondly, decorative type is to enhance the ornamental effect of cable knitting by various methods and other subsidiary materials. Thirdly, avant-garde type is applied in various ways with exaggerated volumes or textures using the three-dimensional effects of cable knitting. Through this study, we look forward to the possibility of expressing the unique aesthetic characteristics of each of the various knitting techniques.

Assessment of Grid Sensitivity in the FDS Field Model to Simulate the Flame Propagation of an Electric Cable Fire (케이블 화재의 화염전파 해석을 위한 FDS 모델의 격자민감도 평가)

  • Kim, Sung-Chan;Lee, Seong-Hyuk
    • Journal of the Korean Society of Safety
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    • v.23 no.4
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    • pp.30-35
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    • 2008
  • The present study has been conducted to examine the effect of grid resolution on the predicted results for electric cable fire using pyrolysis model in FDS(Fire Dynamics Simulator, version 5). The grid independent test for different grid resolutions has been performed for a PE coating cable and the grid resolution is defined by the non-dimensional characteristic length of fire and mean grid size. The calculated maximum heat release rate and mean flame spread rate were almost constant for higher grid resolution of 20${\sim}$25 and the computing time for the grid resolution takes approximately 20hours to solve flame propagation with pyrolysis model. The geometrical simplification of a electric cable dose not greatly affect on the maximum heat release rate and flame spread rate and the rectangular approximation of cable shape gives acceptable result comparing with the round cable with stepwise grid.