Despite the efforts in research and development of brake systems there still is

a lack of procedures to evaluate the robustness of brake systems with respect to brake noise

during the development process. Hence, there is a steadily growing need for the identification

of a brake’s modal properties using experimental methods. Experience shows that these

modal properties can change rapidly due to variations in operating conditions or due to

manufacturing tolerances.

Based on a previously presented comparison of excitation concepts [18], the most promising

concept is chosen and continuously improved. Subsequently, two approaches to evaluate the

robustness of brake systems are introduced. On one hand the modal analysis to identify

system’s resonance-frequencies and modal damping values and on the other hand the work of

the friction force that is characteristical for the self-extitation mechanism [15].The presented

work includes a more detailed view of the actuation system, the experimental modal analysis

in particular for a full brake system under braking conditions as well as the measurement of

the friction force. Moreover, it shows experimentally the dependence of the systems resonance

frequencies and modal damping on operating conditions and the differences in the results of

introduced approaches. Consequently, a new method is developed, in order to allow the

modal analysis of a complete brake system with the goal to approximate the systems inherent

robustness.

The results of this investigation, consisting of the identified modal properties of a full brake

system, depending of different operating conditions, as well as the calculated work of the

friction force are shown and discussed with respect to the systems robustness. Hence, this

work provides an outlook to future methods in fast robustness detection of brake systems.

Philippe Stegmann, Sebastian Kruse - Audi AG Ingolstadt, Development Foundation Brake; Klaus Augsburg - Ilmenau University of Technology