Study on Characteristics of Headliner SR Noise According to Its Material and Temperature Condition for Vehicle

摘要

As the interior noise of automobiles is reduced compared to the past, controlling unexpected SR noise of vehicles has become an important factor of customer satisfaction. Accordingly, SR-related research has mainly been done on hard trim components such as seat, door trim, and cockpit modules and many improvements have been made. However, this does not mean that soft trim components are exceptionally free of SR noise. Among soft trim parts, headliner is directly coupled with parts such as lamp, plastic case, and wiring. For this reason, field claims of headliners are on an increasing trend. In this study, to confirm the SR noise according to headliner base, the headliners were made of PPGF (Poly-Propylene Glass Fiber) and PU (Poly-Urethane) base. Also, the headliner noises were measured at low, room and high temperature in order to confirm SR noise change under extreme conditions. For the test environment reproducing the vehicle driving, the headliners were excited with a magnetic shaker. As a result, it was confirmed that the headliner noises were greatly affected by plastic peripheral components. And SR noise of the headliner has been emphasized especially at the low temperature condition, which is expected due to the increase of the gap and the rigidity caused by the thermal reduction of the peripheral parts, but a close analysis is needed in the future. The headliner with PU was found to be more advantageous in SR than the PPGF in the same configuration. It was confirmed that the PU substrate having relatively low flexural strength generates small noises even in the case of large self-trembling.