Design of C/SiC Composite Brake Disc for AALRT Finite Element Method
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Date
2016-06
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Addis Ababa University
Abstract
Gray cast iron is commonly used brake disc material with high density that increase fuel
consumption. It also generates heat easily during braking due to its lower specific heat capacity
which affects its mechanical properties. The ever increasing demand for high speed trains from
passengers and reduction of maintenance costs by operators means a compelling need to develop
new disc brake materials with higher friction performance and longer service life. An interesting
alternative are C/SiC composite materials characterized by lower wear rate and higher resistance
to thermal shock. During braking kinetic energy transforms in to thermal energy resulting to
intense heat and high temperature in the brake disc-pad interface. Thus, induced thermal loads
determine thermo-elastic behavior of the railway disc brake structure.
This paper is mainly concerned with design analysis of C/SiC composite material to study and
evaluate the performance under severe braking conditions and there by assist in brake disc design
and analysis. Geometric dimensions of AA LRT train disc are taken on to CATIA where the 3D
model is imported to ANSYS for determining the temperature distribution, variation of stresses
and deformation produced in the disc brake after applying the boundary conditions. The main
boundary and initial condition are the heat flux on the braking surface of the disc and the force of
the brake clamps. Two different disc designs are used, one solid and other the ventilated existing
one to demonstrate the material response for each variant. The aim is to investigate the structural
deformation of the brake disc due to combined effect of thermal expansion when subjected to
temperature change during the braking cycle and thereby assist the railway industry in developing
optimum and effective disc brake material. The results were found to be satisfactory.
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Keywords
Brake disc, stress, heat flux, C/SiC composite, reinforcement fibers, transient response, friction coefficient, contact pressure