EFFECT OF HEAT TREATMENT ON CRACK PROPAGATION AND PERFORMANCE OF DISK BRAKE WITH CROSS DRILLED HOLES |
Yunhwa Hong, Taeksu Jung, Chongdu Cho |
Inha University |
|
|
|
|
ABSTRACT |
A vehicle disk brake, which has cross drilled hole patterns on a frictional surface for improving cooling and
braking performance, has propensity to cause crack problem under the harsh braking condition. In this study, the finite element
analysis by using ABAQUS was adopted to investigate a cause of crack occurrence by the thermo-mechanical phenomenon
around drilled hole patterns. As a remedy of the crack generation, the disk brake rotor with stress relieving and ferritic
nitrocarburizing was prepared and tested on brake dynamometer in harsh condition. The test result was examined in terms of
pad wear, the braking torque variation, the braking temperature changes, the crack initiation timing, and the crack propagation
speed. As a test result, the disk after heat treatment showed 3.61 % higher average braking temperature than the disk without
heat treatments, to suggest decreased heat dissipation performance, however, it also showed 14 % lower pad wear amount, and
0.1 % smaller braking torque variance than the disk without heat treatments, to stand for improved contact characteristics.
Also, the heat treated brake rotor showed 51.3 % lower crack propagation rate which is considered as proper countermeasure
of the fracture phenomenon at the edge of cross drilled hole. |
Key Words:
Disk brake, Heat treatment, Stress relieving, Ferritic nitrocarburizing, Thermal crack, Crack propagation |
|
|
|