Search Results

This paper discusses the approach and application of controlling material and manufacturing parameters in development of lightweight acoustic interior systems. First addressed is the theoretical premise of noise control mechanisms and their relationship to material property/process sensitivity through poroelastic model simulation. The optimal balance of sound transmission loss and absorption in achieving optimally tuned acoustic performance is then presented along with material sample and in-vehicle experimental results. The ability to acoustically tune the vehicle interior to a desired sound level and frequency content through proper design & control of the elastic porous properties achieved by unique acoustic material/process flexibility & capability is demonstrated.

The disc brake corner assembly is comprised of several subsystems (brake pad, caliper, rotor etc.) which have interfaces between two or more of these structures. The brake pad assembly as the subsystem connecting the rotor to the caliper has specific areas of contact which influence the onset and potential to control brake squeal. The primary excitation interface occurs between the friction pad and rotor surface. The contact is initiated by the piston apply force on the brake pad insulator. Contact interface reaction forces, displacements and deformations are generated and form the natural and geometric boundary conditions of the overall system. Brake squeal characteristics are strongly affected by these conditions. The study focuses on brake system dynamic response to interface contact conditions. The brake insulator and pad assembly interacting with the brake piston as well as caliper are evaluated.

The brake insulator performs a significant function when properly designed in controlling the brake system high frequency dynamic instabilities leading to brake squeal. The second major challenge is thermal management. It provides the direct heat flow, storage and corresponding temperature differential profile between the rotor and piston. Suboptimal thermal control can lead to lower operational bands of damping outside of the peak loss factor range, variation in modal dynamics with temperature, heat aging and degradation of elastomer/visco-elastic polymer physical properties [2, 3]. Design of the insulator is dictated by the unique squeal signature (and associated thermal cycles) specific to the brake corner architecture. Short time frame insulator solutions are typically required in the later development stages with no latitude for design modification flexibility.