• Title/Summary/Keyword: equivalent rectangular plate

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Numerical investigation of a plate-type steam generator for a small modular nuclear reactor

  • Kang, Jinhoon;Bak, Jin-Yeong;Lee, Byung Jin;Chung, Chang Kyu;Yun, Byongjo
    • Nuclear Engineering and Technology
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    • v.54 no.8
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    • pp.3140-3153
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    • 2022
  • A numerical feasibility study was conducted to investigate the thermal-hydraulic characteristics of a steam generator with corrugated plates for a small modular reactor. Accordingly, a one-dimensional thermal-hydraulic analysis code was developed based on the existing state-of-the-art thermal-hydraulic models and correlations for corrugated plate heat exchangers. Subsequently, the pressure loss, heat transfer, and instability characteristics of the steam generator with corrugated plates were investigated according to the chevron angle and mass flux. Additionally, the characteristics of rectangular and disk-type corrugated plate steam generators with equivalent heat transfer areas were analyzed. The steam generator with disk-type corrugated plates exhibited better performance in terms of pressure loss and heat transfer rate than the rectangular type. In addition, when the mass flux decreased from the onset of boiling points, reverse gradients of the total pressure change were observed in both types. Thus, it was confirmed that Ledinegg instability could occur in the steam generator with corrugated plates. However, it was dependent on the chevron angle, and the optimal chevron angle to minimize instability was 45° under the conditions of the present analysis.

A Study on the Mobility of Power Tiller in Wetland Rice Field (수도포장(水稻圃場)에서의 동력경운기(動力耕耘機) 주행성(走行性)에 관(関) 연구(硏究))

  • Lee, Kyou Seung;Lee, Yong Kook;Lee, Choong Yong;Park, Seung Je;Kim, Sang Hun
    • Journal of Biosystems Engineering
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    • v.9 no.2
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    • pp.8-18
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    • 1984
  • To investigate the most important factors affecting the mobility of power tiller and to find the method which can be used for predicting the mobility of power tiller in soft paddy field, a series of field experiment was performed with two models of power tiller (8ps and 6ps diesel). From the results obtained throughout field experiment, the following conclusions were derived. 1. The wheel sinkage of power tiller during both traveling and field operations, which mainly influence the mobility, could be predicted from both plate ($50{\times}100mm$) sinkage and soil cone index (30-degree cone with 2 and $6cm^2$ base area). 2. Prediction of wheel sinkage from the rectangular plate sinkage was found to be more suitable compared with the cone index. 3. The upper limit of rectangular plate sinkage was found as 15 centimeter for operation of power tiller in muddy field which is equivalent of $1kg/cm^2$ of $2cm^2$ cone index value.

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Vibration analysis of the plates subject to dynamic concentrated loads by using spectral element method (스펙트럴요소법을 이용한 동적집중하중을 받는 평판의 진동해석)

  • Lee, Joon-Keun;Lee, U-sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.3
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    • pp.635-643
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    • 1998
  • A spectral element method(SEM) is introduced for the vibration analysis of a rectangular plate subject to dynamic concentrated loads. First, the spectral plate element is derived from the relations between the forces and displacements along the two opposite edges of plate element. The global spectral matrix equation is then formulated by assembling two spectral plate elements so that the dynamic concentrated load is located at the connection nodal line between two plate elements. the concentrated load is then spatially Fourier transformed in the direction of the connection nodal line to transform the two-dimensional plate problem into a simplified equivalent one-dimensional beam-like problem. We may benefit from these procedures in that the spectral results from the present SEM is compared with the exact analytical solutions to prove the remarkable accuracy of the present SEM, while this is not true for conventional finite element solutions, especially at high frequency.

A Study on the Crushing Theory of Double Hatted-section Tube (이중 모자형 단면부재의 압괴 연구)

  • Kim, C.W.;Han, B.K.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.3 no.3
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    • pp.29-36
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    • 1995
  • The present paper deals with the crushing characteristics of double hatted-section tube used in body structure of passenger car. Being crushed, a double hatted-section tube shows symmetric or antisymmetric buckling mode according to section aspect ratio and flange size. Zone of buckling mode is shown by numerical methods. It is supposed that crippling behavior of double hatted-section tube corresponds with rectangular tube without flange. Crippling plate coefficient is also calculated when section aspect ratio of tube is higher than one.

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New Radiating Edges-Coupling (REC) Model for the Gap Between Two Rectangular Microstrip Patch Antennas (구형 마이크로스트립 안테나의 간격에 대한 새로운 Radiating Edges-Coupling(REC) 모델)

  • Hong, Jae-Pyo;Cho, Young-Ki;Son, Hyon
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.2
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    • pp.56-65
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    • 1989
  • In this paper, a new model is presented which characterizs the coupling of the radiating edges between two rectangular microstrip patch antennas. This model, namely Radiating Edges-Coupling (REC) model, is derived from the equivalent circuit of the slitted parallel-plate waveguide filled with homogeneous dielectric. Applying the REC model to two coupled rectangular microstrip patch antennas, we obtain numerical S-parameter values of |$S_{11}$| and |$S_{12}$|for the various coupling separations, $S_e$=0.5, 1.0, 1.5, and 2.0mm. Theoretical results are in fairly good agreement with experimental results.

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Static Bending Strength Analysis of Two Rectangular Plates Spot-welded Using Finite Element Method (유한요소법에 의한 점용접된 두 사각평판의 정적굽힘강도해석)

  • Han, Geun-Jo;Kim, Tae-Hyung;Ahn, Sung-Chan;Shim, Jae-Joon;Han, Dong-Seop
    • Proceedings of the KSME Conference
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    • 2001.06a
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    • pp.842-847
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    • 2001
  • In order to reinforce the plate in bending spot-welding method is usually used. To analyze the effect of the reinforcement of the plates spot-welded, finite element method was employed to take advantage of the deflection obtained with respect to the change of the aspect ratio and area ratio. The reinforcement effect represented by the equivalent thickness. Was maximum when the aspect ratio was around $1.2{\sim}1.6$ and the area ratio was 0.05.

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A Study on the Characteristics of a Piezoelectric Ceramic Transformer with divided Electrodes (전극분할형 압전변압기의 특성에 관한 연구)

  • 허두오;강태구;조철환;이해민;안형근;한득영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.11a
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    • pp.270-273
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    • 1996
  • This paper describes a type of piezoelectric transformer with improved design principles. It consists of a thin rectangular piezoelectric ceramic plate having two input electrodes and one output electrode. The length of each input and output electrode is nearly one third of that of piezoelectric transformer itself. In the driving section, the ceramic plate is poled in the thickness direction reversely with each other, and has electrodes on both main faces. The electric input near its fundamental resonance frequency is applied to the driving section in parallel and the output voltage from the generating section is connected to the resistor load. Its equivalent circuit is derived from the Mason\`s model. The frequency characteristics near the resonance frequency under no load have been investigated. Moreover, using this piezoelectric transformer we measured the LCD backlight characteristics.

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Cost-effectiveness dynamics and vibration of soft magnetoelastic plate near rectangular current-carrying conductors

  • AliAsghar Moslemi Beirami;Vadim V. Ponkratov;Amir Ebrahim Akbari Baghal;Barno Abdullaeva;Mohammadali Nasrabadi
    • Structural Engineering and Mechanics
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    • v.88 no.2
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    • pp.159-168
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    • 2023
  • Cost-effective high precision hybrid elements are presented in a hierarchical form for dynamic analysis of plates. The costs associated with controlling the vibrations of ferromagnetic plates can be minimized by adequate determination of the amount of electric current and magnetic field. In the present study, the effect of magnetic field and electric current on nonlinear vibrations of ferromagnetic plates is investigated. The general form of Lorentz forces and Maxwell's equations have been considered for the first time to present new relationships for electromagnetic interaction forces with ferromagnetic plates. In order to derive the governing nonlinear differential equations, the theory of third-order shear deformations of three-dimensional plates has been applied along with the von Kármán large deformation strain-displacement relations. Afterward, the nonlinear equations are discretized using the Galerkin method, and the effect of various parameters is investigated. According to the results, electric current and magnetic field have different effects on the equivalent stiffness of ferromagnetic plates. As the electric current increases and the magnetic field decreases, the equivalent stiffness of the plate decreases. This is a phenomenon reported here for the first time. Furthermore, the magnetic field has a more significant effect on the steady-state deflection of the plate compared to the electric current. Increasing the magnetic field and electric current by 10-times results in a reduction of about 350% and an increase of 3.8% in the maximum steady-state deflection, respectively. Furthermore, the nonlinear frequency decreases as time passes, and these changes become more intense as the magnetic field increases.

Application of the Laplace transformation for the analysis of viscoelastic composite laminates based on equivalent single-layer theories

  • Sy, Ngoc Nguyen;Lee, Jaehun;Cho, Maenghyo
    • International Journal of Aeronautical and Space Sciences
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    • v.13 no.4
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    • pp.458-467
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    • 2012
  • In this study, the linear viscoelastic response of a rectangular laminated plate is investigated. The viscoelastic properties, expressed by two basic spring-dashpot models, that is Kelvin and Maxwell models, is assumed in the range to investigate the influence of viscoelastic coefficients to mechanical behavior. In the present study, viscoelastic responses are performed for two popular equivalent single-layered theories, such as the first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT). Compliance and relaxation modulus of time-dependent viscoelastic behavior are approximately determined by Prony series. The constitutive equation for linear viscoelastic material as the Boltzmann superposition integral equation is simplified by the convolution theorem of Laplace transformation to avoid direct time integration as well as to improve both accuracy and computational efficiency. The viscoelastic responses of composite laminates in the real time domain are obtained by applying the inverse Laplace transformation. The numerical results of viscoelastic phenomena such as creep, cyclic creep and recovery creep are presented.

Calculation of Phase Center of Large Geomorphological Object on the Surface

  • Kim Jun-su;Park Sang-Eun;Kim Duk-jin;Moon Wooil M.
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.741-744
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    • 2005
  • A numerical scattering model for artificial metal structure based on physical optics approximation is developed to identify the height of phase center, and the result is compared with interferometric SAR DEM. The interferometric SAR data were gathered by AIRSAR during PACRIM- II campaign on Jeju Island. Power transmission towers on piedmont pasture along the slopes of Mt. Halla look like elliptic risings in TOPSAR DEM. The heights of risings are quantitatively analyzed using a scattering model in the way of achieving the height of phase centers of power transmission towers. A numerical algorithm is developed on the basis of physical optics approximation. The structure of power transmission tower was decomposed into hundreds of rectangular metal plates, of which the scattering matrix is known in analytic form, and the calculated scattering fields were summed coherently. The effect of direct backscattering component, ground-scatterer component and scatterer-ground component are decomposed and computed individually for each rectangular metal plate. The $\Deltak-radar$ equivalent was used to calculate height of phase center of the scatterer. The heights of a selected power transmission tower and scattering algorithm results give existence and location of the transmission towers but not actual tower heights.

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