FEM変位法を用いた2次元流体連成振動解析

概要

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There are many structural vibration problems which include fluid motion, such as an oil-filled power transformer tank. In fluid vibration analysis, the wave equation is commonly solved using the velocity potential or pressures as unknown variables in FEM, FDM and BEM. On the other hand, for structural vibration analysis, displacements are generally used as unknown variables. However, it is difficult to solve problems involving vibration of fluid and structure simultaneously by taking into account fluid-structure interactions, except by using added masses instead of fluid, or Herrmann's special variational principle. These approaches include special and complex techniques which are unfamiliar to most engineers. In this paper, a new vibration calculation method which can treat fluid and structure simultaneously is proposed, using an FEM displacement method which is familiar to most engineers. When the displacement method is applied to two-or three-dimensional fluid vibration, spurious vibration modes caused by excessive degrees of freedom are observed. These modes are not only bothersome but also hinder analysis accuracy. First, the generation process of the spurious modes was clarified. Then a rejection technique for them was developed. Finally, the new calculation method was applied to solve coupled vibrations of fluid and structure. The method was judged to be applicable to actual vibration analysis.
社団法人日本機械学会の論文
1994-04-25