Evaluation of Acoustic Performance of Automotive Seats by Experimental and Simulation Techniques

Automotive seats play a vital role for improving the overall sound absorption inside the vehicle. To understand the acoustic performance of automotive seats in the passenger compartment of a vehicle, various types of seat assemblies were tested by the reverberation chamber method as per ASTM C423. The methodology has been developed to test the seats based on seats position in the chamber and minimum requirement of seats to evaluate the accurate sound absorption and Reverberation Time (RT). The effect of various seat cover materials like leather and cloth fabrics on the seat sound absorption and RT has been determined experimentally. Study of various cover materials (leather/vinyl and cloth fabrics) with PU foam for sound absorption characteristics has been carried out using simulation technique. The intrinsic parameters used as inputs in above steps are evaluated using specialized test rigs. The complex sound speed, propagation constant and surface impedance characteristics are predicted for a typical multilayer seat configuration. Further Sound absorption is predicted and compared with impedance tube results to validate the predicted parameters. Finally effect of various seat configurations on operator ear Sound Pressure Levels (SPL) at driver/passenger ear location inside a typical car cabin studied using Boundary Element Method (BEM) simulation.