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Brake squeal is a problem that has been faced by several methods in the last decade. Among then, finite element analysis is proving to be a useful tool to predict the noise occurrence of a particular brake system during the design stage. The Finite Element Method (FEM) has been employed to detect unstable frequencies using a complex eigenvalue analysis. These unstable frequencies are related, in most cases, with high sound pressure levels generated during the brake system operation and its detection is an important step in order to produce quiet brake systems. Although the method is fast and provides guidance for solving engineering problems, it is very sensitive to input parameters like material properties and boundary conditions. For brake system modeling, the determination of the contact stiffness between rotor and pads is a crucial point, since one of the major contributing mechanisms to generate squealing frequencies is the modal coupling between these two components.

During the last years, the automotive industry dedicated great efforts to understand and solve the noise problem from disc brake systems. There are several types of brake noise problems, each one related with a frequency range of occurrence. In most cases, the customer perceives the noise as a vehicle problem and demand having it fix by their dealer. As a consequence, disc brake noise is one of the major contributors to the automotive manufactures warranty costs, leading the automotive industry to look for ways to control it. A large class of disc brake noise problems is associated with the resonant behavior of an operating brake system. However, the detection of these brake system modes during the operating condition can be very expensive, demanding the use of inertial dynamometers and laser vibrometer measurements.