Impact of textile soiling in wheel arch's acoustic properties

Abstract

The aim of this project is to evaluate the influence of textile soiling in the acoustic absorption of a wheel arch. In order to evaluate the influence of soiling it is carried out both a soil study characterization and an acoustic absorption measurement on real wheel arch samples. First, soil study starts with a short literature overview where the mechanisms of soil retention are analyzed. The field wheel arch study concerns visual observation of wheel arch’s special features followed by particle size measurement and soil visual and elemental analysis. These analysis were performed with a Laser Difraction equipment and a Scanning Electronic Microscope. Results conclude a range of particle size for soil collected and the identification of soil elemental composition, among other soiling features concerning textile porosity. The second part involves acoustic measurements for determining the airflow resistance value and the acoustic absorption coefficient of the same soiled textile analyzed before. Same measurements are repeated after removing soil from samples to see how much of the acoustic absorption can be restored. The determination of the acoustic absorption coefficient is performed with an impedance tube. Results show not only a null acoustic absorption in the soiled samples but also an insuficient improvement in the absorption after cleaning. Airflow resistance results prove that porosity is completely clogged even after cleaning. The paper concludes with short proposal for preserving textile from soiling and therefore maintain the original acoustic absorption