Abstract:
Rattle noise is directly tied to customers' perceptions of product quality. The accurate and efficient prediction of this noise component remains an important and challenging area. Sound-pressure levels (SPLs) in the acoustic field of a rattling plate were measured experimentally and compared to predictions based on the plate's equations of motion. The aluminum plate was hinged at one end and contacted a point at the other. Rattle was induced by exciting the plate supports using a shaker with a sinusoidal input. SPL measurements were made with a microphone at different points in the acoustic field. For the initial theoretical predictions, the plate was modeled as a rigid body and a closed-form solution was found for the linearized equations of motion to obtain the contact forces. The calculated force was used to generate the predicted plate vibration which, in turn, was used to predict the SPL in the acoustic field surrounding the plate. Later in the study, plate flexibility was added into the contact force model, and the effects of adding an increasing number of vibrational modes were studied. The experimental and theoretical data were compared in the time and frequency domains.