Transient Thermo Elastic Analysis of Disk Brake

Abstract

Thermo elastic instability is caused by frictional heating and thermal deformation of the surfaces when two bodies slide against each other, and alters the original contact configuration. Even if the surfaces are perfectly flat at the outset, instability will lead to a departure from flatness. Above a certain critical speed, a nominally uniform pressure distribution is unstable, giving way to localization of load, excessive heat generation and hence to hot spots at the sliding interface (Barber, 1969), (Kennedy and Ling, 1974), (Floquet and Dubourg, 1994), (Bryant, et al, 1995), (Kao et al., 2000). The problem is particularly prevalent in energy dissipation systems such as brakes and clutches. Hot spots can cause material damage (i.e. wear) and undesirable frictional vibrations, known as ``hot roughness'' or ``hot judder'' (Kreitlow, et al, 1985), (Inoue, 1986), (Zagrodzki, 1990), (Anderson, 1990), (Lee, 1998).The present paper describes the use of ANSYS simulation software to perform a transient analysis of the thermo elastic contact problem for disk brakes. The numerical simulation for the thermo elastic behavior of disk brake is obtained in the repeated brake testing carried out on a dynamometer. The computational results are presented for the distribution of heat flux and temperature on each friction surface between the contacting bodies.. In addition, comparisons of the thermal behavior of the different brake pad materials with respect to disk materials have been discussed.