• Title/Summary/Keyword: 직사각형판

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Equation for Estimating Natural Frequencies of Initially Stressed Rectangular Plates (초기응력을 받는 직사각형판의 고유진동수 산정식 개발)

  • Park, Sung-Jin
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.1
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    • pp.150-159
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    • 2014
  • A simplified method for the calculation of buckling and vibrational characteristics of initially stressed rectangular plate and antisymmetric angle-ply laminated plates is presented in this paper using the natural frequencies under unloading state. The equation of motion of rectangular plate with two opposite edges simply supported is investigated on the basis of Rayleigh-Ritz method and Mindlin plate theory with effect of the curvature term. The relationships of the non-dimensional natural frequencies with initial stresses the coeffcients of critical buckling and the boundaries of the dynamic principal instability region can be characterized by the non-dimensional natureal frequencies under unloading state. Numerical examples are presented to verify the simplified equations and to illustrate potential applications of the analysis.

Free Vibration Analysis of Rectangular Plate with a Rectangular Cutout (직사각형 구멍을 갖는 직사각형판의 자유진동해석)

  • Kwak, Moon-K.;Han, Sang-Bo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.593-599
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    • 2005
  • This paper is concerned with the vibration analysis of a rectangular plate with a rectangular hole. Even though there have been many methods developed for the addressed problem, they suffer from computational time. In this paper, we developed a new methodology called Independent Coordinate Coupling Method which can couple two independent coordinate systems for the entire plate domain and the hole. By matching the deflection condition imposed on the expressions, the relationship between the global axes and the local axes is derived. This formula is then used for the calculation of the eigenvalue problem. The numerical results show the efficacy of the proposed method.

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Free Vibration Analysis of Rectangular Plate with Multiple Rectangular Cutouts by Independent Coordinate Coupling Method (독립좌표연성법을 이용한 여러 개의 직사각형 구멍을 갖는 직사각형 평판의 자유진동해석)

  • Kwak, Moon-K.;Song, Myung-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.9
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    • pp.881-887
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    • 2007
  • This paper is concerned with the vibration analysis of a rectangular plate with multiple rectangular holes. Even though there have been many methods developed for the addressed problem, they suffer from computational time. In this paper, we applied the Independent Coordinate Coupling Method(ICCM) to the addressed problem, which was developed to compute natural vibration characteristics of the rectangular plate with a rectangular hole and proven to be computationally effective. The ICCM is based on Rayleigh-Ritz method but utilizes independent coordinates for each hole domain. By matching the deflection conditions for each hole imposed on the expressions, we can easily derive the reduced mass and stiffness matrices. The resulting equation is then used for the calculation of the eigenvalue problem. The numerical results show the efficacy of the Independent Coordinate Coupling Method.

A Space-Tapering Approach for a Rectangular Array (직사각형 어레이를 위한 공간체감 방법)

  • Chang, Byong-Kun
    • The Journal of the Acoustical Society of Korea
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    • v.14 no.1
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    • pp.115-122
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    • 1995
  • It is practical to taper the element (e.g., antenna or sensor) spacing with uniform weight rather than to taper the weights with uniform spacing. In a rectangular array, a triangular grid geometry of elements is more economical than a rectangular grid geometry in terms of reducing the number of elements. A space-tapering approach is proposed to improve the performance of a rectangular phased array with a triangular grid geometry of elements above a ground plane. The effects of space tapering on the main beam width and sidelobe level are discussed. It is shown that the proposed approach improves the sidelobe performance while the main beam width becomes a little broader.

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Free Vibration Analysis of Rectangular Plate with a Rectangular Cutout by Independent Coordinate Coupling Method (독립좌표연성법을 이용한 직사각형 구멍을 갖는 직사각형 평판의 자유진동해석)

  • Kwak, Moon K.;Han, Sangbo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.12 s.105
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    • pp.1398-1407
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    • 2005
  • This paper is concerned with the vibration analysis of a rectangular plate with a rectangular hole. Even though there have been many methods developed for the addressed problem, they suffer from computational time. In this paper, we developed a new methodology called Independent Coordinate Coupling Method which can couple two independent coordinate systems for the entire plate domain and the hole. By matching the deflection condition imposed on the expressions, the relationship between the global axes and the local axes is derived. This formula is then used for the calculation of the eigenvalue problem. The numerical results show the efficacy of the proposed method.

Vibration and Buckling of the Rectangular Plate Loaded by Varying In-plane Stress (변분포 평면응력을 받는 직사각형 판의 진동과 좌굴 해석)

  • 신영재;윤종학;황기섭;지영철;로엘
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.05a
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    • pp.651-656
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    • 2004
  • This paper presents the application of Differential Transformation to the bucking load and the vibration problem of the rectangular plate loaded by varying in-plane stress. Numerical calculations are carried out and compared with previously published results to validate the results of the resent method. The results obtained by this method agree well with those reported in the Devious works. The results obtained by the present method are presented for various non-uniform loads.

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A Study on the Ultimate Strength According to the Boundary Condition of a Ship Plate under Thrust (압축하중을 받는 선체판의 경계조건에 따른 최종강도에 관한 연구)

  • 고재용;박주신;이돈출
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2002.11a
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    • pp.89-93
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    • 2002
  • One of the primary factors like plate structure in ship is redundancy structure that is comparable with ocean structure and frame structure. The more component material becomes buckling collapsed locally the less structure stiffness becomes accordingly. As a result, by increasing the load distribution of my other subsidiary structure continually component member collapses, therefore the structure could be in danger of collapse. So, in order to interpret this phenomenon precisely, the study on boundary condition of the ship's plate and post-buckling analysis must be considered In this study, the rectangular plate is compressed by the in-plane load Buckling & Ultimate strength characteristics are applied o be the elasto-plasticity large deformation by ansys code with F.E.M method On this basis, elasto-plasticity of the plain plate are investigated. This study proved elasto-plasticity behaviour of the ship's plate in accordance with boundary condition based on the series analysis in case of the compressive load operation

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A Study For Vehicle License Plate Extraction Using DCT (DCT를 이용한 자동차번호판 추출에 관한 연구)

  • 경보현;손태주;전호상;이학찬;남성기;남궁재찬
    • Proceedings of the Korean Information Science Society Conference
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    • 1999.10b
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    • pp.318-320
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    • 1999
  • 본 논문에서는 디지털 카메라를 통해 얻어진 자동차 영상으로부터 이산코사인변환(Discrete Cosin Transform : DCT)를 이용한 자동차번호판 추출방법을 제안한다. 번호판은 문자와 배경으로 이루어져 있으며 번호판 내에는 문자들이 조밀하게 모여 있다는 특징과 번호판 영역이 직사각형으로 되어 있다는 것을 이용하여 DCT에 의해서 자동차영상에서 수직, 수평, 대각선 성분만을 추출한후 이 추출된 에지영상에서 코릴레이션(Correlation)을 이용하여 번호판영역을 검출하고 이 검출된 번호판영역을 투영 히스토그램(Histogram)에 의해서 날씨가 흐리거나 아주 밝거나 밤에 찍은 영상들에 대해서는 번호판 추출이 힘들었다. 그러나 제안된 본 논문은 날씨와 납과 밤에 상관없이 일관된 번호판 영상을 추출할 수 있었다.

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Investigating the Spatial Focusing of Time Reversal Lamb Waves Using a Virtual Sensor Model on a Rectangular Plate (직사각형 판에서 가상탐지자 모델을 이용한 시간반전램파의 공간모임 규명)

  • Park, Hyun-Woo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.24 no.5
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    • pp.553-567
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    • 2011
  • During the last three years, the possibility of the time reversal Lamb waves has been paid attention to for structural health monitoring of a plate. This study proposes a numerical scheme which can simulate the spatial focusing of time reversal Lamb waves on a rectangular plate. In this scheme, a time reversal process is formulated in the frequency domain using active virtual sensors being equivalent to the mirror effects of an actual sensor due to wave reflection on the plate boundary. Forward and backward Lamb wave propagations are represented by scalar functions for simulating the spatial focusing of time reversal Lamb waves. The validity of the proposed scheme is demonstrated through the comparison to the results of finite element analysis in which the spatial focusing of time reversal Lamb waves is realized by wafer-type piezoelectric(PZT) transducers collocated on a rectangular plate.

Free Vibration Analysis of Rectangular Plate with Multiple Circular Cutouts by Independent Coordinate Coupling Method (독립좌표연성법을 이용한 여러 개의 원형 구멍을 갖는 직사각형 평판의 자유진동해석)

  • Kwak, Moon K.;Song, Myung-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.11
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    • pp.1086-1092
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    • 2007
  • This paper is concerned with the vibration analysis of a rectangular plate with multiple circular holes. On the contrary to the case of rectangular plate with multiple rectangular holes, it is very difficult to perform qualitative analysis on natural vibration characteristics because of geometrical inconsistency. In this paper, we applied the Independent Coordinate Coupling Method(ICCM) to the addressed problem, which was developed to compute natural vibration characteristics of the rectangular plate with a circular hole and proven to be computationally effective. The ICCM is based on Rayleigh-Ritz method but utilizes independent coordinates for each hole domain. By matching the deflection conditions for each hole imposed on the expressions, we can easily derive the reduced mass and stiffness matrices. The resulting equation is then used for the calculation of the eigenvalue problem. The numerical results show the efficacy of the Independent Coordinate Coupling Method.