• Title/Summary/Keyword: computational investigation

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Micro-Tribological Investigation for Temperature Rise in Multi-layered Thin Films (다층 박막의 온도상승에 대한 마이크로 트라이볼로지적 조사)

  • Kim, Joon-Hyun;Shin, Kyung-Ho
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.760-765
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    • 2000
  • The study deals with the development of a computational procedure for evaluating the temperature rise in dry and lubricated multi-layered contacts of head/disk interface. A transient computational model with a transformed rectangular computational domain is utilized. A model and a computational method for micro-contact with sub-lubricated zone, including friction heat generation, have been presented. The model was applied, taking full account of the changes in contact area and contact load due to frictional heating. The computational distribution of temperature is obtained with the analytical findings for various composition and contact conditions. Especially, a rapid rise ($220^{\circ}C$ or above) in read head temperature lese to a saturation in the influence of a thermal spike on signal performance. This general class of problems can be treated provided that heat generation distribution and layer properties are known.

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Effect of Car-Crash at Edge Beam of U-Channel Bridge based on Korean Highway Bridge Specifications and AASHTO LRFD Bridge Design Specifications (도로교 설계기준 및 AASHTO LRFD 설계기준에 근거한 U-채널 교량측보의 차량충돌의 영향)

  • Choi, Dong-Ho;Na, Ho-Sung;Lee, Kwang-Won
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2008.04a
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    • pp.490-494
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    • 2008
  • U-Channel Bridge is effective bridge type, because its edge beam performs role of barrier and enables to reduce additional dead loads. Although it is effective to reduce additional dead loads, there is possibility of bridge collapse under impact load due to car crash. Also, edge beam must have ability to induce safe driving and prevent falling accidents. Therefore, it requires behavior analysis and property investigation through the vehicle impact crashing edge beam. This study presents method of structural analysis of U-channel bridge and investigates design specifications for the effect of the edge beam under the vehicle impact. Also, it carries out stability investigation of behavior of edge beam and slab, based on Korean Highway Bridge Design Specifications and AASHTO LRFD Bridge Design Specification.

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Numerical investigation of The characteristics of Biaxial Flexure Specimens (수치해석을 이용한 이방향 휨인장 시험체의 특성분석)

  • Kim, Ji-Hwan;Zi, Goang-Seup;Kang, Jin-Gu;Oh, Hong-Seob
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2008.04a
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    • pp.614-617
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    • 2008
  • This paper presents the numerical investigation of the characteristics of biaxial flexure specimens for the Biaxial Flexure Test(BFT) which was recently developed to measure the biaxial tensile strength of concrete. Using FEM, the effect of size and eccentricity on the specimens was evaluated. The parameters such as radious of the support and the loadings, thickness and free length were studied. The results of the FE analysis were entirely consistent with the predictive solution, when b/agt;0.4, h/alt;0.6 and the thickness of the specimens were increased. On the other hands, when b/agt;0.4, those with lesser free length showed good results. To limit the difference between the stresses at the end points of 2b as the specimen was sustained and the stress at the center point of the specimen are not over 10%, lateral eccentricity was analyzed to be in the limits of 3%.

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Design of R.C.Members with General Shape Subjected to Biaxial Bending (2축휨과 축하중을 받는 임의 단면 형태의 철근 콘크리트 부재의 설계)

  • 문선미;이종권;이병해
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1993.10a
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    • pp.139-148
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    • 1993
  • A computerized numerical method is presented for the design and/or the investigation of RC members with general shape and material properties subjected to axial load and biaxial bending moment. Slenderness effects can also be considered with the use of the moment magnification factor. The method is based on the summation of stress result- ants on a small area of the cross section which enables the determination of strength interaction diagrams, load contours and moment-curvature relationships for the general section. Thus the presented program HYCOL can be used as a direct tool for design and/or investigation of RC members with general shape subjected to biaxial bending. The accuracy of program HYCOL is established by comparison with experimental results.

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Numerical investigation of tip clearance effects on the performance of ducted propeller

  • Ding, Yongle;Song, Baowei;Wang, Peng
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.7 no.5
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    • pp.795-804
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    • 2015
  • Tip clearance loss is a limitation of the improvement of turbomachine performance. Previous studies show the Tip clearance loss is generated by the leakage flow through the tip clearance, and is roughly linearly proportional to the gap size. This study investigates the tip clearance effects on the performance of ducted propeller. The investigation was carried out by solving the Navier-Stokes equations with the commercial Computational Fluid Dynamic (CFD) code CFX14.5. These simulations were carried out to determine the underlying mechanisms of the tip clearance effects. The calculations were performed at three different chosen advance ratios. Simulation results showed that the tip loss slope was not linearly at high advance due to the reversed pressure at the leading edge. Three type of vortical structures were observed in the tip clearance at different clearance size.

Analytical Investigation on the Behavior of Simple Span Integral Abutment Bridge (단경간 일체식교대 교량의 거동에 대한 해석적 연구)

  • 홍정희;정재호;박종면;유성근;윤순종
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.04a
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    • pp.99-106
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    • 2002
  • This paper presents an analytical investigation on the behavior of simple span integral abutment bridge. An integral abutment bridge is a simple span or multiple span continuous deck type bridge having the deck integral with the abutment wall. Although the temperature variation and earth pressure are the major attributor to the total stress in integral abutment bridge, the superstructure has been designed by modeling it as a simple or continuous beam In order to investigate the effect of temperature change and earth pressure on the superstructure of integral bridge, the simple span integral bridge is modeled as a plane frame element. Performing frame analysis, the variations of bending moment and axial force of superstructure due to the various loading combination are investigated with respect to the flexural rigidity of piles, and the bending moment and axial force obtained by frame analysis are compared with the maximum bending moment obtained by conventional design method and initial prestressing force respectively.

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An Estimation of the Consequence Analysis for Asphyxiation Accident in Confined Space using C.F.D. (CFD를 활용한 밀폐공간 가스질식사고의 피해 영향 평가)

  • Cho, Wan Su;Kim, Eui Soo
    • Journal of the Korean Society of Safety
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    • v.33 no.5
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    • pp.28-34
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    • 2018
  • Recently, various engineering approaches have been widely used in the accident investigation field to identify the cause of the accident and to predict damage by accident. Computational analysis is the most commonly used method of accident investigation technique. This technique is mainly used to identify the mechanism of the accident generation and to determine the cause when it is difficult to reproduce the situation at the time of the accident or when it is impossible to perform a reproduction experiment. In this study, The computational fluid dynamics analysis for nitrogen asphyxiation accident generated by defect of building structural between diffusion outlet and cooling tower was performed to determine the inflow path of the suffocation gas, death possibility by concentration of suffocation gas and predicted the time of death due to the accident using 3D modeling and FLACS program. We can quantify diffusion concentration of asphyxiation gas and predict mechanism of death occurrence by accident and evaluate the consequence Analysis through this study. In the future, This method can be widely used in the field of gas safety by improving the reliability and validity of the analysis.