Thermal Stress Analysis of Disc Brake Rotor By Finite Element Method
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Date
2013-12
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Abstract
Disc brakes are exposed to large temperature resulting large thermal stress during routine
braking. These large temperature extrusions have two possible outcomes: fade that generates
reduction in stopping power; and large amount of plastic deformation that generates low fatigue
life in the brake rotor. The aim of the present work is to investigate the temperature and thermal
stress response of gray cast iron disc brake during first braking phase using analytical, as well as
finite element (FE) method and comparing the result. The area of study is concentrated on
temperature variation as a function of thickness only. Only the areas exposed to high temperature
is selected for analysis, specifically the rotor, by excluding hub and vanes because they are for
from disc-pad contact. One particular existing brake disc design for a SUV car of model
DD6470C is chosen for the investigation. The dimensions, material property and maximum
allowable speed of this car are used as an input both for analytical and finite element method.
Analytically the distribution of temperature caused by applied heat flux as a function of disc
thickness is solved by the method of partial solutions. The finite element simulation for the
coupled transient thermal field and stress field is carried out by separate data base thermalstructural
coupled method based on ANSYS 14.0 to evaluate the stress fields and temperature.
Due to circumferential and axial symmetry of the disc, only half thickness of the disc is used
axially, and 15.65° is used circumferentially in finite element analysis by ANSYS. The results
show maximum temperature and compressive stress components at the surface and these affects
tribological properties such as damage and failure at the surface of the disc. In addition, it was
found that high thermal load leads to brake fade and low fatigue life time of cast iron due to
surface rupture of the rotor. Good agreement was obtained between FEM and analytical analysis
braking cycles to failure.
Key words: Analytical analysis, Heat flux, Finite element method, Stress components,
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Keywords
Analytical analysis; Heat flux; Finite element method; Stress components