Assessment of Squeak and Rattle Noise of a Car Seat Using 3D Sound Intensity Measurements

Assessment of squeak and rattle noise of a car seat using 3D sound intensity measurements Squeak and Rattle (S&R) noises are transient sound events occurring when adjacent parts come into contact, either impacting or sliding. All components and sub-systems integrated in a vehicle may produce noise when excited with certain vibro-acoustic load. S&R noise can be linked to the perceived build quality, durability and even discomfort or annoyance. As a result, car manufacturers have strict regulations to prevent noise issues. Current vibro-acoustic validation tests can vary in complexity from full vehicle simulation to component level tests. Additionally, subjective assessments are often required to locate problematic areas and quantify their relevance. In this paper, S&R noise of a car seat is investigated using 3D sound intensity measurements. A multi-axial shaker is used to drive the seat with a short time-stationary excitation extracted from a road profile. Results show that both active and reactive intensity are very effective for assessing S&R problems. Furthermore, a methodology is proposed to localize the elements that produce a significant acoustic excitation and evaluate their relative annoyance.