Prof. Dr. Peter Blaschke, TH-Wildau, GERMANY

Mr. Daniel Alarcon, TH-Wildau, GERMANY

Key parameters with regard to the NVH behavior of brake discs are their natural frequency and damping behavior.

In particular, the dynamic modulus of elasticity usually is assumed as a constant value in the FE-calculation for cast iron. However, the raw material and the entire production process play an important role to set the young’s modulus and the damping. Due to the cooling effect, the parameters (stiffness and damping) can differ on the circumference of the disc. These parameters can be identified using different experimental methods after the test.

In this paper a physical background, theory and test methods will be discussed to understand the different methods to characterize brake discs.

Mayor topics:

An (almost) non-mathematical introduction to the spatial, modal and response models.

The Frequency Response Function as a problem-solving tool.

Measurements using Microphones / accelerometers / Scanning Laser Doppler Vibrometers.

Automatic impact excitation: challenges and opportunities. Excitation and identification of in-plane modes of brake discs and pads.

Linearity Check.

Identification of non-proportional damping.

Practical aspects of brake disc testing.