• Title/Summary/Keyword: 강구조물

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An Image Processing Algorithm for a Visual Weld Defects Detection on Weld Joint in Steel Structure (강구조물 용접이음부 외부결함의 자동검출 알고리즘)

  • Seo, Won Chan;Lee, Dong Uk
    • Journal of Korean Society of Steel Construction
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    • v.11 no.1 s.38
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    • pp.1-11
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    • 1999
  • The aim of this study is to construct a machine vision monitoring system for an automatic visual inspection of weld joint in steel structure. An image processing algorithm for a visual weld defects detection on weld bead is developed using the intensity image. An optic system for getting four intensity images was set as a fixed camera position and four different illumination directions. The input images were thresholded and segmented after a suitable preprocessing and the features of each region were defined and calculated. The features were used in the detection and the classification of the visual weld defects. It is confirmed that the developed algorithm can detect weld defects that could not be detected by previously developed techniques. The recognized results were evaluated and compared to expert inspectors' results.

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Influence of the Random Yield Strength Distribution on the Behaviour Factor of Steel Structures (임의항복강도의 분포가 강구조물의 거동계수에 미치는 영향)

  • Kook, Seung Kyu
    • Journal of Korean Society of Steel Construction
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    • v.9 no.2 s.31
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    • pp.229-235
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    • 1997
  • In order to check the influence of the randomness in yield strengths on the energy dissipation capacity of steel structures, behaviour factors applied for the "Response Spectrum Method" and their distributions are determined in this study with 7 steel framed models. Also 4 artificial accelerograms simulated with a given spectrum are applied to check the influence of the randomness in seismic action on the behviour factor. To execute numerous time-step calculations for the investigation a time-step analysis method is developed and applied after the reliability estimation to determine the action effects.

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Unified Section and Shape Discrete Optimum Design of Planar and Spacial Steel Structures Considering Nonlinear Behavior Using Improved Fuzzy-Genetic Algorithms (개선된 퍼지-유전자알고리즘에 의한 비선형거동을 고려한 평면 및 입체 강구조물의 통합 단면, 형상 이산화 최적설계)

  • Park, Choon Wook;Kang, Moon Myung;Yun, Young Mook
    • Journal of Korean Society of Steel Construction
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    • v.17 no.4 s.77
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    • pp.385-394
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    • 2005
  • In this paper, a discrete optimum design program was developed using the refined fuzzy-genetic algorithms based on the genetic algorithms and the fuzzy theory. The optimum design in this study can perform section and shape optimization simultaneously for planar and spatial steel structures. In this paper, the objective function is the weight of steel structures and the constraints are the design limits defined by the design and buckling strengths, displacements, and thicknesses of the member sections. The design variables are the dimensions and coordinates of the steel sections. Design examples are given to show the applicability of the discrete optimum design using the improved fuzzy-genetic algorithms in this study.

Nondestructive Inspection of Steel Structures Using Phased Array Ultrasonic Technique (위상배열 초음파기법을 이용한 강구조물의 비파괴 탐상)

  • Shin, Hyeon-Jae;Song, Sung-Jin;Jang, You-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.20 no.6
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    • pp.538-544
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    • 2000
  • A phased array ultrasonic nondestructive inspection system is being developed to obtain images of the interior of steel structures by modifying a medical ultrasound imaging system. The medical system consists of 64 individual transceiver channels that can drive 128 array elements. Several modifications of the system were required mainly due to the change of sound speed. It was necessary to fabricate array transducers for steel structure and to obtain A-scan signal that is necessary for the nondestructive testing. Boundary diffraction wave model was used for the prediction of radiation beam field from array transducers, which provided guidelines to design array transducers. And a RF data acquisition board was fabricated for the A-scan signal acquisition along a selected un line within an image. For the proper beam forming in the transmission and reception for steel structure, delay time was controlled. To demonstrate the performance of the developed system and fabricated transducers, images of artificial specimens and A-scan signals for selected scan lines were obtained in a real time fashion.

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