• Title/Summary/Keyword: Least square and integration methods

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Modeling of Are Light Intensity and Its Application to Weld Seam Tracking in GMAW (GMA용접의 아크빛 모델 및 용접선 추적에의 응용)

  • 유용상;최상균;유중돈;선우희권
    • Journal of Welding and Joining
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    • v.14 no.5
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    • pp.113-121
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    • 1996
  • The arc sensor has been most widely used for weld seam tracking through welding current or voltage variation. In this work, the relation between the arc light intensity and welding condition is investigated using heat balance in the Plasma for its possible application to seam tracking in the GMAW process. The arc light intensity is derived to be the function of the arc length and welding current Experiments are carried out to verify the proposed heat balance model. Performances of least square and integration methods to process the signals for seam tracking are compared experimentally. Predicted arc light intensity shows reasonably good agreement with experimental results. The weld seam is successfully tracked through the arc light intensity. The least square and integration methods demonstrate almost same performance of seam tracking with $CO_2$gas shielding.

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An Improved Finite Element Method by Adding Arbitrary Nodes in a Domain (임의의 절점 추가에 의한 개선 유한요소법)

  • Kim, Hyun-Gyu
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.12 s.255
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    • pp.1626-1633
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    • 2006
  • In the present paper, in the context of the meshless interpolation of a moving least squares (MLS) type, a novel method which uses primary and secondary nodes in the domain and on the global boundary is introduced, in order to improve the accuracy of solution. The secondary nodes can be placed at any location where one needs to obtain a better resolution. The support domains for the shape functions in the MLS approximation are defined from the primary nodes, and the secondary nodes use the same support domains. The shape functions based on the MLS approximation, in an integration domain, have a single type of a rational function, which reduces the difficulty of numerical integration to evaluate the weak form. The present method is very useful in an adaptive calculation, because the secondary nodes can be easily added and moved without an additional mesh. Several numerical examples are presented to illustrate the effectiveness of the present method.

Electromagnetic Field Analysis Using the Point Collocation Method Based on the FMLSRK Approximation

  • Kim, Hong-Kyu;Chong, Jin-Kyo;Park, Kyong-Yop;Kim, Do-Wan
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.4B no.4
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    • pp.180-183
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    • 2004
  • This paper presents a description of the point collocation method and its application to the electromagnetic field computation. The interpolation scheme is based on the fast moving least square reproducing kernel approximation. In the method, the integration cell is not required and the essential boundary conditions can be enforced directly. Numerical simulations on 1-D and 2-D problems are carried out to validate the method. It is found that computational efficiency is higher than the general mesh-free methods.