Order domain analysis of speed-dependent friction-induced torque in a brake experiment

• Published in: Journal of sound and vibration Vol. 331; no. 23; pp. 5040 - 5053
• Main Authors: Sen, Osman Taha, Dreyer, Jason T., Singh, Rajendra
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 05.11.2012; Elsevier
• Subjects: Amplitudes; Applied sciences; Brakes; Clearances; Drives; Exact sciences and technology; Excitation; Fundamental areas of phenomenology (including applications); Mathematical analysis; Mathematical models; Mechanical contact (friction...); Mechanical engineering. Machine design; Physics; Rotors; Shafts, couplings, clutches, brakes; Solid mechanics; Structural and continuum mechanics; Torque; Vibration, mechanical wave, dynamic stability (aeroelasticity, vibration control...); Juddering; Pressure fluctuation; Geometrical shape; Tracking; Mechanical torque; Forced vibration; Motor torque; Mechanical contact; Mechanical clearance; Experimental study; Modeling; Surface metrology; Friction; Vehicle direction; Tracking(movable target); Brake; Profilometry
• ISSN: 0022-460X; 1095-8568
• DOI: 10.1016/j.jsv.2012.06.011

A friction-induced forced vibration problem, as excited by the geometric distortions of the brake rotor, is studied in this article. The focus is on the order domain analysis, as the speed-dependent behavior of friction torque is not well understood. First, a new laboratory experiment is constructed to simulate vehicle brake judder in a scientific and yet controlled manner. The variations in pressure and torque are measured as the rotor slows down, and the order domain tracking is used to construct shaft torque vs. speed diagrams. A quasi-linear model of the laboratory experiment is then developed to obtain an analytical solution and to estimate the torque envelope function. A nonlinear model of the laboratory experiment (with a clearance) is also investigated to examine the resonant amplitude growth. Finally, predictions are successfully compared with measurements. Several contributions emerge over the prior literature. In particular, the experimental data clearly show that multiple-orders of the rotor surface distortion profile excite the friction-induced torque, and a clearance in the torsional system controls the resonant amplitude regime. New analytical and numerical solutions provide much insight into the speed-dependent resonant amplitude growth process. ► Design of a laboratory experiment for brake judder studies. ► Quasi-linear and nonlinear models of the test setup. ► Significance of the rotor surface distortion profile on brake torque response. ► Experimental validation of models.