Thermoelastic effects in brakes

3D Measurements of Lubricant and Surface Temperatures Within an Elastohydrodynamic Contact

“…The resulting temperature rise can lead to materials melting [1], cracking [2], oxidising [3,4] or deforming [5], especially under dry conditions. Under lubricated conditions, temperature rises caused by friction can affect fluid properties such as film thickness, traction, shear stress, additive reaction and can even cause degradation [6] or film failure [7].…”

An Experimental Investigation of Frictionally-Excited Thermoelastic Instability in Automotive Disk Brakes Under a Drag Brake Application

“…This interaction is unstable if the sliding speed is sufficiently high, in which case perturbations develop in the nominal pressure distribution, leading eventually to localized contact and the development of hot spots. The phenomenon is now generally referred to asfrictionally-excited thermoelastic instability or TEL Experimental observations of TEI have been reported in many practical applications, particularly in railway (Wentenkamp and Kipp, 1976;van Swaaij, 1979;Dow, 1980;Fee and Sehitoglu, 1985) and aircraft brakes (Santini and Kennedy, 1975). However, interest in the phenomenon in the automotive industry is more recent, being prompted by changes in braking materials and other design improvements.…”

Multifunctionality of nonasbestos organic brake materials

“…The performance defining attributes (PDAs) of such heterogeneous materials need to be predicted on the basis of micro-mechanics analyses, while taking into account some of the design variables to a useful level of accuracy [11]. Similarly too little of abrasive inclusion makes the frictional response inadequate whereas too much of the same causes rotor incompatibility and generates severe thermo-elastic instabilities (TEI) [18,19]. For example, too little resin reduces its strength due to inadequate binding leading to excessive wear, whereas too much of the same contributes to friction fade at elevated temperatures [15][16][17].…”