| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1999: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
At first, a program of finite element method for three-dimensional transient eddy current analysis has been developed and computational accuracy and reduction of computation time have been investigated. And transient analysis of eddy current problems and electromagnetic field problems was evaluated to estimate computational accuracy of integration with respect to time. A guideline to choose a method for the transient analysis of electromagnetic field with high accuracy has been established after making systematic summary of the results. It became clear that both the time-stepping method and the Fourier transform method are suitable for the transient analysis in the case of using finite element method. On the other hand, a fundamental study of adaptive mesh generation has been done for high-accuracy finite element analysis.
Next, in order to develop an analysis method for the evaluation of pulsed eddy current testing probes, using two and three dimensional finite element methods for the approximation of geometry of computation model, the time-stepping method and the Fourier transform method for the approximation of time integration are investigated by the comparison between calculated results and measured data. At the results, when fine meshes are used, almost same results can be obtained by the time-stepping method and the Fourier transform method. When computational error of harmonic components arises because of the use of coarse meshes, nonphysical oscillation appears in the solution of the Fourier transform method, and computational error of the magnitude appears in the solution of time-stepping method. Finally, it became clear that the Fourier transform method is suitable for the evaluation of exciting wave form because recalculations of field analysis are not necessary for different excitations, and the time-stepping method is suitable for the various types of analysis because there is no serious restriction.
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