抄録
The authors used Mindlin's equation, and calculated the natural mode of a circular plate with a solid shaft under the boundary condition of a fixed inner diameter. As the result, the calculated natural frequency of the low mode of the thick circular plate differed greatly from the one measured by modal analysis. The causes were analyzed on the (1, 0) mode of vibration, which had the biggest error, of 78 percent. It was revealed that the elastic deformation on the boundary between the circular plate and the solld shaft, and the bending deformation of the shaft had a strong influence on the natural frequency. By taking both influences into account, the natural frequency of the (1, 0) mode was corrected to within a 5 percent error.
