Title: A Finite Element Method for Effective Reduction of Speaker-Borne Squeak and Rattle Noise in Automotive Doors
text: Increasing sound quality with advanced audio technology has raised the bar for perceived quality targets for minimal interior noise and maximal speaker sound quality in a passenger vehicle. Speaker-borne structural vibrations and the associated squeak and rattle have been among the most frequent concerns in the perceived audio quality degradation in a vehicle. Digital detection of squeak and rattle issues due to the speaker-borne structural vibrations during the digital vehicle development phase has been a challenge due to the physical complexity involved. Recently, an effective finite element method has been developed to address structure-borne noise [1] and has been applied for detecting the issues of squeak and rattle in passenger vehicles due to vehicle-borne vibrations at vehicle, component and subcomponent levels [2, 3, 4, 5, 6, 7, 8]. In this paper, the speaker-borne structural vibrations are simulated accurately by adapting the critical audio loads in terms of equivalent structural excitations. The squeak and rattle analysis method is extended to predict the potential squeak and rattle issues in a door system on which the speaker is mounted. Using the method, the root causes for the issues are identified and counter-measures are developed to improve the audio quality in the system effectively. Audio tests are conducted to confirm the improvement in the audio quality with the counter-measures adapted. The finite element predictions show very close correlation with the tests regarding the squeak and rattle issues with the baseline design as well as the audio quality enhancement with the counter-measure.