• Title/Summary/Keyword: Flexible Shape

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Study on Convergence Technique through Flow Analysis at the Flexible Joint of the Pipe Laying (배관의 신축이음에서의 유동해석을 통한 융합기술연구)

  • Lee, Jung-Ho;Cho, Jae-Ung
    • Journal of the Korea Convergence Society
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    • v.6 no.3
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    • pp.13-18
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    • 2015
  • This paper is the study on the safe design of joint controling the pressure and temperature by connecting between pipes laying with the flexible joint. This study aims at decreasing the excessive pressure applied in the pipe and preventing the accident occurrence in order to solve the pipe damage by extraction and contraction due to the pressure of open air and transport gas. The flow properties of each model are investigated through the simulation analysis by applying three kinds of the flexible joints. When transport gas passes the flexible joint, the flow characteristics of heat, pressure and velocity at pipe laying are analyzed. It is thought to be contributed to the safe design due to the shape of the flexible joint by using the result of this study. And it is possible to be grafted onto the convergence technique at design and show the esthetic sense.

Appropriate Boundary Conditions for Three Dimensional Finite Element Implicit Dynamic Analysis of Flexible Pavement (연성포장의 3차원 유한요소해석을 위한 최적 경계조건 분석)

  • Yoo, Pyeong-Jun;Al-Qadi, Imad L.;Kim, Yeon-Bok
    • International Journal of Highway Engineering
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    • v.10 no.4
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    • pp.213-224
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    • 2008
  • Flexible pavement responses to vehicular loading, such as critical stresses and strains, in each pavement layer, could be predicted by the multilayered elastic analysis. However, multilayered elastic theory suffers from major drawbacks including spatial dimension of a numerical model, material properties considered in the analysis, boundary conditions, and ill-presentation of tire-pavement contact shape and stresses. To overcome these shortcomings, three-dimensional finite element (3D FE) models are developed and numerical analyses are conducted to calculate pavement responses to moving load in this study. This paper introduces a methodology for an effective 3D FE to simulate flexible pavement structure. It also discusses the mesh development and boundary condition analysis. Sensitivity analyses of flexible pavement response to loading are conducted. The infinite boundary conditions and time-dependent history of calculated pavement responses are considered in the analysis. This study found that the outcome of 3D FE implicit dynamic analysis of flexible pavement that utilizes appropriate boundary conditions, continuous moving load, viscoelastic hot-mix asphalt model is comparable to field measurements.

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Fabrication of Biofuel Cell Roll Using Flexible CNT Nanosheet Substrate (유연한 CNT Nanosheet 기판을 이용한 생체연료전지 Roll 제작)

  • Sung, Jungwoo;Lim, Geunbae
    • Journal of Sensor Science and Technology
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    • v.23 no.6
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    • pp.388-391
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    • 2014
  • The most promising application of the biofuel cells is implantable devices, so the biofuel cells should have an appropriate shape for the vascular vessel. We demonstrated the biofuel cell roll for using in tubes. MWNTs were aggregated by vacuum filtration on a nitrocellulose membrane filter, which was biocompatible and flexible. The MWNT aggregated nitrocellulose membrane used the electrodes of the biofuel cells because it was conductive as well as nanostuructured. Then, the membrane was rolled into the roll shape. The maximum power density of the biofuel cell roll was $7.9{\mu}W/cm^2$ at 153mV and 50 mM glucose. Also, the power density is expected to increase in its practical application if there is flow in the tube, which makes the transportation of fuel easy. The biofuel cell roll contacts with the wall of the tube, so flow in the tube does not disturb. Also, the biofuel cell roll has multi-layers offering more electroactive area.

A Study of Printing Mark Shape for the Flexible Display (유연 디스플레이 인쇄를 위한 인쇄 마크 형상 연구)

  • Hong, Sun-Ki;Lee, Duck-Hyoung;Jung, Hoon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.2
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    • pp.51-57
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    • 2010
  • The shape of the register mark for the image processing becomes very important, because the printing quality is determined by the error correction between the register marks for the image processing. In this paper, printing marks are developed using the image process for the gravure printing method which is commonly being used in roll to roll, high resolution printing. The marks which can be cited to the flexible display print are developed The developed register marks which satisfies 10[${\mu}m$] error tolerance are tested under 70[mpm] printing conditions and confirmed through the experiments.

Force density ratios of flexible borders to membrane in tension fabric structures

  • Asadi, H.;Hariri-Ardebili, M.A.;Mirtaheri, M.;Zandi, A.P.
    • Structural Engineering and Mechanics
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    • v.67 no.6
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    • pp.555-563
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    • 2018
  • Architectural fabrics membranes have not only the structural performance but also act as an efficient cladding to cover large areas. Because of the direct relationship between form and force distribution in tension membrane structures, form-finding procedure is an important issue. Ideally, once the optimal form is found, a uniform pre-stressing is applied to the fabric which takes the form of a minimal surface. The force density method is one of the most efficient computational form-finding techniques to solve the initial equilibrium equations. In this method, the force density ratios of the borders to the membrane is the main parameter for shape-finding. In fact, the shape is evolved and improved with the help of the stress state that is combined with the desired boundary conditions. This paper is evaluated the optimum amount of this ratio considering the curvature of the flexible boarders for structural configurations, i.e., hypar and conic membranes. Results of this study can be used (in the absence of the guidelines) for the fast and optimal design of fabric structures.

Biomechanical Efficacy of a Combined Flexible Cage with Pedicle Screws with Spring rods: A Finite Element Analysis (Spring rod를 사용한 척추경 나사못과 동반 시술된 Flexible cage의 생체역학적 효과)

  • Kim, Y.H.;Park, E.Y.;Kim, W.H.;Hwang, S.P.;Park, K.W.;Lee, Sung-Jae
    • Journal of Biomedical Engineering Research
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    • v.38 no.1
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    • pp.9-15
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    • 2017
  • Recently, flexible cages have been introduced in an attempt to absorb and reduce the abnormal load transfer along the anterior parts of the spine. They are designed to be used with the pedicle screw systems to allow some mobility at the index level while containing ROM at the adjacent level. In this study, a finite element (FE) study was performed to assess biomechanical efficacies of the flexible cage when combined with pedicle screws with flexible rods. The post-operated models were constructed by modifying the L4-5 of a previously-validated 3-D FE model of the intact lumbar spine (L2-S1): (1) Type 1, flexible cage only; (2) Type 2, pedicle screws with flexible rods; (3) Type 3, interbody fusion cage plus pedicle screws with rigid rods; (4) Type 4, interbody fusion cage plus Type 2; (5) Type 5, Type 1 plus Type 2. Flexion/extension of 10 Nm with a compressive follower load of 400N was applied. As compared to the Type 3 (62~65%) and Type 4 (59~62%), Type 5 (53~55%) was able to limit the motion at the operated level effectively, despite moderate reduction at the adjacent level. It was also able to shift the load back to the anterior portions of the spine thus relieving excessively high posterior load transfer and to reduce stress on the endplate by absorbing the load with its flexible shape design features. The likelihood of component failure of flexble cage remained less than 30% regardless of loading conditions when combined with pedicle screws with flexible rods. Our study demonstrated that flexible cages when combined with posterior dynamic system may help reduce subsidence of cage and degeneration process at the adjacent levels while effectively providing stability at the operated level.

Optimal placement of piezoelectric curve beams in structural shape control

  • Wang, Jian;Zhao, Guozhong;Zhang, Hongwu
    • Smart Structures and Systems
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    • v.5 no.3
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    • pp.241-260
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    • 2009
  • Shape control of flexible structures using piezoelectric materials has attracted much attention due to its wide applications in controllable systems such as space and aeronautical engineering. The major work in the field is to find a best control voltage or an optimal placement of the piezoelectric actuators in order to actuate the structure shape as close as possible to the desired one. The current research focus on the investigation of static shape control of intelligent shells using spatially distributed piezoelectric curve beam actuators. The finite element formulation of the piezoelectric model is briefly described. The piezoelectric curve beam element is then integrated into a collocated host shell element by using nodal displacement constraint equations. The linear least square method (LLSM) is employed to get the optimum voltage distributions in the control system so that the desired structure shape can be well matched. Furthermore, to find the optimal placement of the piezoelectric curve beam actuators, a genetic algorithm (GA) is introduced in the computation model as well as the consideration of the different objective functions. Numerical results are given to demonstrate the validity of the theoretical model and numerical algorithm developed.

A Comparative Study for NHPP Software Reliability Model based on the Shape Parameter of Flexible Weibull Extension Distribution (유연한 와이블 확장분포의 형상모수를 이용한 NHPP 소프트웨어 신뢰성 모형에 관한 비교연구)

  • Kim, Hee-Cheul;Shin, Hyun-Cheul
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.9 no.2
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    • pp.141-147
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    • 2016
  • NHPP software reliability models for failure analysis can have, in the literature, exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, infinite failures NHPP models that repairing software failure point in time reflects the situation, was presented for comparing property. Commonly used in the field of software reliability based on Flexible Weibull extension distribution software reliability of infinite failures was presented for comparison problem. The result is that a relatively small shaping parameter was effectively. The parameters estimation using maximum likelihood estimation was conducted and model selection was performed using the mean square error and the coefficient of determination.. In this research, software developers to identify software failure property follows shape parameter, some extent be able to help is considered.