1985 年 41 巻 5 号 p. 285-290
Rigid body radiation by half sine transient acceleration of a sphere was studied. The results were applied to the estimation of radiated energy due to collision of two spheres. Radiation efficiency and Fourier transform of motion velocity were used for the energy spectrum formulation. Total acoustic energy was evaluated from the spectrum as a function of non-dimensional parameter β=k_da, where k_d is the wave number for transient motion and a is the sphere radius. For impact between two identical spheres, estimates of total radiated energy and peak frequency in the sound pressure spectrum agree well with experimental values. Experimental data were obtained for steel and polymer balls. Value ranges for β, radiated energy and the peak frequency in sound pressure spectrum for a practical situation are shown.