UWE Bristol Engineering showcase 2015

James Schofield
Meng Mechanical Engineering
Project Supervisor Rachel Szadziewska
Investigation to improve the cooling rate of bicycle brake pads.
Background information
At the start of the investigation the report carried out an extensive literature review covering topics ranging from the equations governing heat transfer to the
history of brake pads. The research found that a lot of experimentation and reports had been produced aimed at improving the rate of cooling in the rotor of a
brake disc system but few studies had been undertaken in the field of brake pad cooling. Therefore the report decided to investigate several theoretical ways
that a brake pad could increase its cooling rate.
Theoretical model
An explicit mathematical theoretical model was produced for the investigation to aid in the
design of new brake pads. The theoretical model was used to determine the cooling rate of
the original brake pad design and then to help produce two new brake pad designs and then
model their cooling rate. The theoretical model used was a nodal analysis model where the
heat flux passing into each of the nodes was determined over a discrete time step.
Experiments that were carried out
The report carried out several experiments. The first experiment which was carried out was to
determine experimentally the thermal conductivity of the brake pad material as this value is not
released by manufactures . This value could then be used to accurately model the cooling rate of the
brake pads. The report then measured experimentally the cooling rate of the three designs by
heating the brake pads to a known temperature and then filming them cool using a thermal imaging
camera. The results of which can be seen in the figure in the center of the page. The report then
carried out wear testing using an experimental rig.
Discussion of results
The three different brake pad designs had the same cooling rate
experimentally, this was a surprise as theoretically the different designs had a
different cooling rates.
The wear experimentation that was carried out showed that the brake pads
designed by the report failed to handle the shear stress that was present
during the braking procedure and the therefore the designs were not valid.
Figure to the left: Shows a design 1 brake pad cooling in
1 minute intervals, and the representative thermal key.
The maximum temperature in each image is notated with
a red triangle.
Project summary
An investigation has been carried out to
determine the cooling rate of current brake
pad designs and to produce two new
innovative designs which have a n improved
cooling rate
Project Objectives
• To design a new bicycle brake pad with an
improved cooling rate compared to the
current brake pads on the market
• To determine the validity of these designs
• To determine the wear characteristics of
the brake pads
Project Conclusion
The report concluded that the brake pads that were
produced with the new innovative designs. Did not
perform better than the original brake pad design on
which they were based. This was due to a number of
factors, one of these factors was the air flowing over
the brake pads not passing through the ventilation
holes f the brake pad.
The brake pads that were produced also failed to
perform as well in the wear testing that was carried
out when compared to the original brake pads. This
was due to the added stress concentration’s that were
placed through the friction material in the form of
ventilation holes.