Parametric analyses of thermoelastic instability in disc brakes

Thermoelastic instability (TEI) results in uneven heating of the rotor and the development of hot spots in automotive disk brake systems. The hot spot s cause rotor distortion and thickness variation which can cause torque var iation resulting in brake roughness and low frequency noise. An analytic st udy has been performed using the basic equations developed by Lee and Barbe r(1993) extended to include the pad thickness (Hartsock and Fash, 1999) and partial rotor surface contact with the pad (Lee and Barber, 1995; Ayala et al., 1996). Relevant pad and rotor material properties as well as the pad thickness, rotor thickness and coefficient of friction were varied by a fix ed percentage to determine the effect on the critical speed for TEI, The re lative importance of each parameter was established and the predicted direc tion of change to increase the critical speed was identified.