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In recent years there has been much interest in problems involving the noise prediction and reduction inside and outside the vehicle. Tire/road exterior noise has been considered to be the major vehicle exterior noise source. However, this paper describes an investigation into the characteristics of the air pumping noise mechanism in terms of source locations and directionality. Some rubber tire/road air pumping noise measurements are presented, whereas some predicted results are computed based on the boundary element method (BEM) to display some parameters which are found to be difficult to be obtained experimentally.

Brake squeal, which is a noise, occurs in the range of frequencies 1 to 16 kHz is an important task for research to develop the vehicle passenger comfort. This phenomena has been studied many years theoretically and experimentally to gain better performance of brake and eliminating the squeal problem. The work presented here is focusing on the effect of the brake pad manufacturing on the generation of brake squeal. A simple proposed three-degree of freedom model has been used in the study to simulate the brake components (pad, caliper, and disc). The brake squeal and frequency response of brake pad has been measured at different working conditions (pressure, sliding speed, and brake pad type). A comparison between the theoretical and experimental work has been made and a good agreement was found between the theoretical prediction of the brake assembly natural frequency and the experimental measurement.