• Title/Summary/Keyword: Analytical Analysis

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Automated FEA Simulation of Micro Motor (마이크로 모터의 자동화된 FEA 시뮬레이션)

  • Lee Joon-Seong
    • Journal of the Korea Society for Simulation
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    • v.11 no.3
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    • pp.13-22
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    • 2002

  • This paper describes an automated evaluation of electrostatic field for micro motors whose sizes range 10 to 103um. Electric field modeling in micro motors has been generally restricted to in-plane two-dimensional finite element analysis (FEA). In this paper, the actual three-dimensional geometry of the micro motor is considered. An automatic FE mesh generation technique, which is based on the fuzzy knowledge processing and computational geometry techniques, is incorporated in the system, together with one of commercial FE analysis codes and one of commercial solid modelers. The system allows a geometry model of concern to be automatically converted to different FE models, depending on physical phenomena to be analyzed, electrostatic analysis and stress analysis and so on. The FE models are then exported to the FE analysis code, and then analyses are peformed. Then, analytical analysis and FE analysis about the torque generated by electrostatic micro motor are performed. The starting torque is proportional to $V^2$, the calculated starting torque from the two-dimensional analytical solutions are three times larger than those from the three-dimensional FE solutions.

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Analysis of Magnetic Fields Induced by Line Currents using Coupling of FEM and Analytical Solution (선전류에 의해 발생되는 자장의 해석을 위한 유한요소법과 해석해의 결합 기법)

  • Kim, Young-Sun;Cho, Dae-Hoon;Lee, Ki-Sik
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.55 no.3
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    • pp.141-145
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    • 2006

  • The line current problem(2-dimensional space : point source) is not easy to analyze the magnetic field using the standard finite element method(FEM), such as overhead trolley line or transmission line. To supplement such a defect this paper is proposed the coupling scheme of analytical solution and FEM. In analysis of the magnetic field using the standard FEM. If the current region is a relatively small compared to the whole region. Therefore the current region must be finely divided using a large number of elements. And the large number of elements increase the number of unknown variables and the use of computer memories. In this paper, an analytical solution is suggested to supplement this weak points. When source is line current and the part of interest is far from line current, the analytical solution can be coupling with FEM at the boundary. Analytical solution can be described by the multiplication of two functions. One is power function of radius, the other is a trigonometric function of angle in the cylindrical coordinate system. There are integral constants of two types which can be established by fourier series expansion. Also fourier series is represented as the factor to apply the continuity of the magnetic vector potential and magnetic field intensity with tangential component at the boundary. To verify the proposed algorithm, we chose simplified model existing magnetic material in FE region. The results are compared with standard FE solution. And it is good agreed by increasing harmonic order.

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A Comparative Study on the Determination of the Selenium in Biological Samples using 75Se and 77mSe Nuclides (75Se과 77mSe 핵종을 이용한 생물시료 중의 셀렌 분석에 대한 비교 연구)

  • Moon, Jong-Hwa;Kang, Sang-Hoon;Kim, Sun-Ha;Chung, Yong-Sam;Kim, Young-Jin
    • Analytical Science and Technology
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    • v.18 no.1
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    • pp.23-26
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    • 2005

  • Se is well known as an anti-oxidant trace element and many customers are interested in an analysis and contents of Se in the various foodstuff samples. This study was aimed at establishig and comparing an analytical method for the determination of the Se in biological samples by neutron activation analysis using two nuclides, $^{75}Se$ and $^{77m}Se$. Keeping this objective, three NIST biological standard reference materials were chosen and the concentrations of the Se were determined under the prefixed analytical conditions such as the irradiation, decay and measurement time. The measured values by both analytical methods were evaluated with certified values. In addition, the detection limits and measurement uncertainty for the analytical results using $^{75}Se$ and $^{77m}Se$ were compared with each other.

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