Acoustic radiation due to the inelastic impact of a sphere on a rectangular plate

Impact between two structures is an important source of noise in industry. However, it is not a well-known phenomenon from a theoretical point of view. The models available in the literature for impact noise often address only part of the phenomenon. In this paper, a more comprehensive model is developed. The acoustic radiation due to the inelastic impact of a sphere with a rectangular simply supported thin plate is formulated and validated experimentally. The impact force is calculated from Hertz's law, which has been extended to the case of plastic deformations, and the acoustic radiation in the time domain is obtained using Rayleigh's integral, the plate being discretized in rectangular elements. The model is used to show that the sound-radiation mechanism includes two separate sources: the initial deformation of the plate and the propagation of the bending waves. The model is also used to determine the contribution to impact noise of parameters that characterize the two impacting structures or the impact configuration such as plasticity, damping, materials, and impact velocity.