Abstract
Whereas the natural frequencies of the bending vibration for plate are derived analytically, the natural frequencies of the torsional vibration can be calculated only approximately. In the previous researches, the natural frequencies for the specified shape of plate are studied, but the relationship between the natural frequencies and the aspect ratio of plate seems not to be investigated. In this paper, the natural frequencies of the plate are calculated by Rayleigh and Ritz method and the relationship between the natural frequencies and the aspect ratio of plate are illustrated. The results shows that the natural frequencies of torsional vibration arise between the natural frequencies of lower order bending vibration for the wide range of the aspect ratio.