Rattle Noise Generated by a Beam Tip Impacting a Baffled Plate

Abstract

The rattle noise radiated by a beam-plate system in contact is modeled using an explicit time formulation. The beam is driven by a constant step force at an initial time that causes the impact of the beam tip with a baffled plate which, in turn, radiates noise. A Finite Element Method is used for the beam modeling and a modal analytical method for the plate modeling. The contact force is computed as a Lagrange multiplier to ensure the pertinent contact condition. The radiating surface of the plate is treated as a pure monopole layer. Results show the rattle noise characteristic features on the contact force, contact point separation and acoustic pressure on a 0.5 s time characteristic simulation. Rattle noise is related to a typical contact force which switches all the time from zero to non-zero values. The influence of the increase plate and beam stiffness on the noise is presented which shows noise when the plate stiffness is decreased with respect to that of the beam.