• Title/Summary/Keyword: Surface plate

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An Experimental Study on the Flexural Strengthening Effect of Reinforced Concrete Beams Flexural Strengthened by CFRP (CFRP로 보강된 철근콘크리트 보의 휨 보강효과에 관한 실험적 연구)

  • Kim, Jae-Hun;Park, Sung-Moo;Kang, Joo-Won;Shin, Seung-Hyup
    • Journal of Korean Association for Spatial Structures
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    • v.6 no.2 s.20
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    • pp.123-129
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    • 2006
  • Recently, many researches have been conducted about reinforced concrete structures strengthened with FRP plates. In case of structures strengthened with FRP plates, the issue of premature debonding FRP plate has been raised through many previous researches. The purpose of this paper is what structural behavior and flexaural capacity of reinforced concrete beams which are strengthened for flexure is investigated about the using secondary ironware in the method of external bonded CFRP plate, and the method of near surface mounted CFRP-Rod. Also, in order to evaluate flexural capacity, experiments of the reinforced concrete beams with exteranl bonded CFRP plate and near surface mounted CFRP-Rod have been compared and investigated.

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Jet Impingement Heat Transfer on a Cylindrical Pedestal Encountered in Chip Cooling (충돌제트를 이용한 Pedestal 형상의 칩 냉각연구)

  • Lee, Dae-Hee;Lee, Joon-Sik;Chung, Young-Suk;Chung, Seung-Hoon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.1
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    • pp.1-8
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    • 2003
  • The heat transfer and flow measurements on a cylindrical pedestal mounted on a flat surface with a turbulent impinging jet were made. The experiments were made for the jet Reynolds number of Re = 23,000, the dimensionless nozzle-to-surface distance of L/d = 2~10, the dimensionless pedestal height of H/D = 0~1.5. Measurements of the surface temperature and the Nusselt number distributions on the plate surface were made using liquid crystal and shroud-transient technique. Flow measurements involve smoke flow visualization and the wall pressure coefficient. The results show that the wall pressure coefficient sharply decreases along the upper surface of the pedestal. However, the pressure increases when the fluid escapes from the pedestal and then collides on the plate surface. The secondary maxima in the Nusselt numbers occur in the region of 1.0 $\leq$ r/d $\leq$ 1.9. Their values for the case of H/D = 0.5 are maximum 80% higher than those for other cases. The formation of the secondary maxima may be attributed to the reattachment of flow on the plate surface which was separated at the edge of the pedestal.

A Visualization Study on the Characteristics of Droplets Impinging on a Hot Surface (고온 열판에 충돌하는 액적의 거동에 대한 유동가시화 연구)

  • Kim, Dong-Yeon;Yi, Seung-Jae;Kim, Kyung-Chun
    • Journal of the Korean Society of Visualization
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    • v.10 no.1
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    • pp.21-26
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    • 2012
  • Hydrophobic characteristics of high temperature metal surface were investigated by high-speed visualization of water droplet impact. An aluminum plate was used as the sample plate and the initial diameter of a water droplet was 2 mm. Transient behavior of a single droplet impinging on the surface with and without heating was captured by using a high speed camera running at 4,000 frames per second. The Leidenfrost phenomenon was demonstrated for the case of $300^{\circ}C$ surface temperature, however there was no rebounding of droplet on the cold plate due to hydrophilic nature. The experimental results show that the shape evolution of a droplet impinging on the surface varies with the Weber number, i.e. the ratio of impact inertia to capillary force. The overall water-repellent characteristics of the heated surface was very similar to that of the super hydrophobic surfaces.

Neutral surface-based static and free vibration analysis of functionally graded porous plates

  • J.R. Cho
    • Steel and Composite Structures
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    • v.49 no.4
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    • pp.431-440
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    • 2023
  • The functionally graded (FG) porous plates are usually characterized by the non-symmetric elastic modulus distribution through the thickness so that the plate neutral surface does not coincide with the mid-surface. Nevertheless, the conventional analysis models were mostly based on the plate mid-surface so that the accuracy of resulting numerical results is questionable. In this context, this paper presents the neutral surface-based static and free vibration analysis of FG porous plates and investigates the differences between the mid- and neutral surface-based analysis models. The neutral surface-based numerical method is formulated using the (3,3,2) hierarchical model and approximated by the last introduced natural element method (NEM). The volume fractions of metal and ceramic are expressed by the power-law function and the cosine-type porosity distributions are considered. The proposed numerical method is demonstrated through the benchmark experiment, and the differences between two analysis models are parametrically investigated with respect to the thickness-wise material and porosity distributions. It is found from the numerical results that the difference cannot be negligible when the material and porosity distributions are remarkably biased in the thickness direction.

Numerical Thermo-Fluid Analysis to the Water Cooling Plate (IGBT 스택용 10kW급 수냉각판 열유동 수치해석)

  • Ryoo, Seong-Ryoul;Mock, Chin-Sung;Cho, Tae-Sik;Kim, Chul-Ju
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1298-1302
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    • 2011
  • The present study deals with the results of a thermo-fluid analysis applied to the cooling plate of the water cooling system developed for IGBT stacks, which was designed to keep the power semi-conductors from over heating problems. The cooling plate is to absorb a maximum quantity of 10kW from 4 IGBTs which are to be placed on both sides of the cooling plate, 2 IGBTs of them on each surface. For the analysis, Adina of CFD Program was used and an analysis was conducted to obtain the knowledges on heat and mass flow at both the plate and fluid flow inside. For the simulation, the operational conditions of a temperature difference of $15^{\circ}C$ for the working fluid and a uniform heat flux of about 92000 $W/m^2$ on the surface in contact with an IGBTs.

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Stress intensity factor in cracked plate reinforced with a plate under mixed mode loading (혼합형 하중항에 있는 판재로 보강된 균열판의 응력세기계수)

  • Lee, Kang-Yong;Kim, Ok-Whan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.3
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    • pp.569-578
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    • 1998
  • The mode I and II stress intensity factors have been calculated theoretically for the cracked plate reinforced with a plate by symmetric spot welding under remote mixed mode loading. This is the extension of authors' previous work for the reinforced cracked plate under remote normal stress. Regardless of loading types, the reinforcement effect gets better as one joining spot is closer to the crack tip and the others are closer to the crack surface, and optimum number of the joining spots can be existed. For the present model, the remote loading parallel to crack surface produces the mode I stress intensity factor.

A Study on the Heat Transfer Characteristics of the Large Dimension Heater Plate for a Semiconductor Process (반도체 표면처리공정용 대면적 히터 플레이트의 열전달 특성에 관한 연구)

  • Lee, Yun-Yong;Kang, Hwan-Kook;Moon, Seok-Hwan
    • Journal of the Korean institute of surface engineering
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    • v.43 no.6
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    • pp.309-314
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    • 2010
  • The numerical study for the effect of various factors that affect the temperature distribution of the process glass installed above the large rectangular heater plate was carried out. For the calculation, heat flux, distance between heat source and process glass plate, effect of vacuum condition and convection in a chamber were considered as important factors. The results showed that the temperature gradient on the glass was increased at the natural convection because of the buoyancy force increases due to the heated air. Also, the more heat flux and distance between the heater plate and glass increases, the more increasing the temperature gradient was. In the case of isothermal heating wall, the temperature variation was smaller than the uniform heat flux condition.

NUMERICAL ANALYSIS OF INTERACTION BETWEEN SUPERSONIC JET AND PERPENDICULAR PLATE

  • Yasunobu T;Matsuoka T;Kashimura H;Setoguchi T
    • Journal of computational fluids engineering
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    • v.10 no.1
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    • pp.39-44
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    • 2005
  • The numerical investigation of the interaction between the underexpanded supersonic jet and the perpendicular plate is carried out using the TVD numerical method. The wave structure in the flowfield and the pressure and temperature distributions on the plate surface are obtained by the numerical analysis. Especially, the influence of self-induced flow oscillation caused by the impinging jet and the characteristic of impinging jet are shown. From the result of the numerical analysis, it is concluded that the pressure and the temperature fluctuations on the plate surface strongly depends on the pressure ratio in the flowfield and the position of plate.

Optimal Design of Micro Actuator Plate Spring Considering Vibration Characteristic (진동 특성을 고려한 마이크로 엑추에이터 판 스프링의 최적설계)

  • 이종진;이호철;유정훈
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.220-225
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    • 2003
  • Recent issue of optical actuator is applying to mobile device. It leads actuator to become smaller than conventional type. This paper proposes the design of micro actuator plate spring and analysis of its vibration characteristic. Considering natural frequency of spindle motor, 1st and 2nd eigenfrequency of micro actuator must avoid its natural frequency. First, magnetic circuit is designed by using fine pattern coil and magnetic force is acquired by simulation program. Then, concept design is achieved by topology optimization. From concept design, micro actuator plate spring is embodied through DOE(design of experiment). Finally, considering vibration characteristic simultaneously, optimal plate spring design is determined by RSM(response surface method).

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A Numerical Study of Turbulent Flow and Heat Transfer due to Slot-jet impinging on a Moving flat plate (이동평판에 작용하는 슬롯 충돌제트의 유동 및 열전달에 관한 수치적 연구)

  • Lee, Jong-Seok;Kim, Dong-Keon;Kim, Moon-Kyung;Yoon, Soon-Hyun;Kim, Bong-Hwan
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.2798-2803
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    • 2008
  • The confined slot air jet impinging normally on a moving flat surface has been investigated numerically by using commercial CFD code Ansys CFX-V11. Turbulent flows are modeled using k-w turbulence model. Two-dimensional turbulent flow is considered. Calculations were conducted for a nozzle-to-plate spacing of eight slot nozzle width, at three Reynolds number(Re=4500, 6700 and 10,000) and four surface-to-velocity ratios i.e. 0, 0.25, 0.5 and 1. Results are compared against corresponding cases for heat transfer from a stationary plate. Local Nusselt number is calculated under constant wall temperature condition. The analysis reveals that the average Nusselt number increases considerably with the jet exit Reynolds number, but decrease with the plate velocity.

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