Article: Significance of squeal in disc brake design Journal: International Journal of Vehicle Design (IJVD) 1998 Vol.19 No.1 pp.124 - 133 Abstract: Squeal is usually not considered as one of the design parameters of disc brakes. The object of this work is to highlight the importance of introducing squeal as a design parameter and to correlate between the disc|s natural frequencies and the frequencies at which squeal occurs. An identification of the modal properties of the disc of a Fiat 128 braking unit is carried out by measuring transfer function data to obtain the disc natural frequencies and their modes of vibration. Using a test-rig that simulates a quarter of the car|s inertia and equipped by the appropriate braking unit, squeal was repeatedly generated, recorded and analysed. A parametric study was then conducted and this showed that the squeal frequencies are always a multiple of one of the previously measured disc natural frequencies. The area of the friction pad, considered as an excitation element, affects remarkably the squeal level and its frequencies. An increase in the pad area in the circumferential direction increases the energy input to the system and consequently increases the squeal level and decreases its frequency. The system damping, assumed to increase with the pad area, causes the disappearance of squeal at a larger contact area. Inderscience Publishers - linking academia, business and industry through research

Title: Significance of squeal in disc brake design

Authors: T.A. Nosseir, M.A.R. Said, N.S. El Nahas, G. Abu El Fetouh

Addresses: Professor, Department of Automotive Engineering, Faculty of Engineering, Ain Shams University, Cairo, Egypt. ' Assistant Professor, Department of Automotive Engineering, Faculty of Engineering, Ain Shams University, Cairo, Egypt. ' Assistant Professor, Department of Automotive Engineering, Faculty of Engineering, Ain Shams University, Cairo, Egypt. ' Graduate Student, Aircraft Factory, AOI, Cairo, Egypt

Abstract: Squeal is usually not considered as one of the design parameters of disc brakes. The object of this work is to highlight the importance of introducing squeal as a design parameter and to correlate between the disc|s natural frequencies and the frequencies at which squeal occurs. An identification of the modal properties of the disc of a Fiat 128 braking unit is carried out by measuring transfer function data to obtain the disc natural frequencies and their modes of vibration. Using a test-rig that simulates a quarter of the car|s inertia and equipped by the appropriate braking unit, squeal was repeatedly generated, recorded and analysed. A parametric study was then conducted and this showed that the squeal frequencies are always a multiple of one of the previously measured disc natural frequencies. The area of the friction pad, considered as an excitation element, affects remarkably the squeal level and its frequencies. An increase in the pad area in the circumferential direction increases the energy input to the system and consequently increases the squeal level and decreases its frequency. The system damping, assumed to increase with the pad area, causes the disappearance of squeal at a larger contact area.

Keywords: brake design; brake noise; brake vibration; disc brakes; squeal; vehicle noise; vehicle vibration; vehicle design.

DOI: 10.1504/IJVD.1998.062098

International Journal of Vehicle Design, 1998 Vol.19 No.1, pp.124 - 133

Published online: 29 May 2014 *

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Title: Significance of squeal in disc brake design

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