A Comprehensive Model for Vibration and Noise Generation of an Impacted Plate

Understanding the mechanism of noise and vibration generation caused by an impacted plate is critical for the development of effective impact noise control technologies. According to the literature, the noise of impacted plates is constituted of an initial transient noise (caused by the plate’s rapid deformation) and ringing noise (caused by the plate’s free vibration). Plate free vibration is caused by reflected bending waves on the plate edge. However, there is no clear distinction between what is considered rapid deformation and what is termed plate’s free vibration. This is because bending waves are generated immediately upon impact. Instead of dividing the emitted acoustic field into initial transient noise and ringing noise, this work investigates the contributions to acoustic radiation from natural low- and high-frequency modes (relative to the plate’s critical frequency). The results, at different times and observation points, are displayed separately for the noise and vibration caused by both supercritical and subcritical plate modes. The results show that both subcritical and supercritical components contribute to the generation of circular and oblique wavefronts. Their destructive interference is responsible for the silent time period for points located on the impact axis as well as the constant main lobe of the plate deformation.