Evolution of hot spots in a disk brake
The figure shows experimental observations of the evolution of
hot spots in an automotive brake disk during drag braking (constant
speed) conditions. The measurements were made by a set of
point infrared sensors arranged along a radius. The complete
test lasted 4 minutes, but is here shown faster than real time.
The actual time, the instantaneous maximum temperature on the disk and the
difference between the instantaneous maximum and minimum
temperatures are tracked below the image. This phenomenon
results from an unstable interaction between frictional
heat generation and thermoelastic distortion known as
Frictionally-excited
Thermoelastic Instability
(TEI).