Mikio Kaji

New Finite Element Field Calculation Technique in Which Continuity of Electric Flux is Satisfied

A new finite element technique to calculate electric field strength accurately has been developed. In this technique, new expressions for potential distribution in an element are derived in order to include electric flux densities as unknowns in basic equations. Trial calculations of coaxial cylinder models were performed by traditional methods and by new methods to examine the accuracy of field strength. The results show that the accuracy of field strength calculated by the new technique is much higher. By the calculation of a spacer which is used in SF6-gas-insulated equipment, the new technique was confirmed to be effective for practical use.

Predicting the Bending Life of Wire Harnesses by CAE Analysis

Through CAE (Computer Aided Engineering) analysis, a method in verifying the reliability of wire harnesses has been developed. The relative displacement of the engine causes the battery cable to bend repeatedly; this may result in cable breakage. By investigating the breakage mechanism of battery cables, we have found a correlation between the strain change and cable breakage. Furthermore, the dynamic profile through CAE analysis has been established, and it is also possible to calculate its strain. Using this method, we can limit the amount of actual tests and predict the bending life of battery cables.

Iteratively generated pseudopotentials in electronic structure calculations

We present an iterative procedure to generate first-principles, norm-conserving pseudopotentials which are of an analytic form and separable by construction with fewer nonlocal projectors than conventional ones. The procedure consists of two steps: First, reference pseudowavefunctions and eigenvalues for an atom are determined by a conventional method. Second, trial pseudowavefunctions and eigenvalues are calculated for the pseudopotentials with adjustable parameters repeatedly until they match the reference ones within some tolerance. The pseudopotentials allow us to evaluate Hamiltonian matrix elements efficiently and less likely to yield spurious solution. Examples for copper and zinc are shown.

NUMERICAL ANALYSIS OF MASS DIFFUSION AND HEAT CONDUCTION PHENOMENA IN METAL/CARBIDE COMPOSITE BY THERMOMIGRATION

If a multi-component composite is heated on one side and cooled on the other, heat conduction occurs, moreover, several components diffuse and are enriched on the hot or cold side of the specimen by the influence of the temperature gradient. This phenomenon is known as thermomigration, and affects the thermal stability of the composite in a high temperature application. In this paper, a numerical analysis was made on the composition and temperature distribution change in the composite by thermomigration. The composite consists of the metal and its carbide. Their compositional distributions are assumed uniform or continuously changed from metal to carbide.