Date of Award

Fall 2002

Document Type

Thesis

Degree Name

Master of Science in Mechanical Engineering - (M.S.)

Department

Mechanical Engineering

First Advisor

Avraham Harnoy

Second Advisor

Zhiming Ji

Third Advisor

Boris Khusid

Abstract

Disc brake noise continues to be a major concern throughout the automotive industry despite efforts to reduce its occurrence. Many articles are written on this subject, but there still is no agreement on what exactly causes disc brake noise and what part of the braking system is responsible for it.

The goal of current research was to build a simplified but inclusive mathematical model of a disc brake system and investigate it using Matlab software. The twodimensional model including damping, Stribeck effect and stick-slip friction was built.

The model is unique in a way that all the similar models have been built using complicated FEM software. It is also unique because it considers the stick-slip phenomenon that has not been considered as a potential source of noise in most models.

The simulation was run in Simulink and gave some valuable insights into the brake noise problem. During this investigation, by changing systems parameters, such as damping coefficients, wheel rotation velocity and pad pressure, the stable and the unstable regions of the system were found.

Probably the main conclusion made from the simulations is that the unstable tangential oscillations can develop in the brake system due to the Stribeck effect (velocity-dependant friction coefficient). Another remarkable conclusion based on the simulation results is that the pad while experiencing stick-slip transitions suppresses the unstable disk oscillations. This seems to be an unobvious effect related to non-linear stick-slip oscillations of the pad, which deserves an additional study.

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