Acoustic Radiation Efficiency Models of a Simple Gearbox.

Abstract : Acoustic intensity measurements were conducted on a simple spur gear transmission in a welded steel housing. The radiation efficiency of the housing was computed from the intensity data for the first three harmonics of mesh frequency. Finite element and boundary element methods (FEM/BEM) were used jointly to model acoustics and dynamics of the top plate of the housing. For a simply supported elastic plate, reasonable agreement was achieved between experimental radiation efficiencies and those predicted with FEM/BEM. However, predictions of the housing characteristics were only partially successful. Four simple analytical models were examined to judge their ability to predict the radiation efficiency. These models do not simulate the modal characteristics of a gearbox; therefore their predictions yield only general trends. Discrepancies are believed to be related to inaccurate modeling of the excitation of the structure as well as to interactions between modes of vibration.