UWE Bristol Engineering showcase 2015

Introduction
Rafael Alberto de Araujo Silva
BEng Mechanical Engineering
DEVELOPMENT OF A REDUCING WEAR SYSTEM TO STORED MILITARY AIRCRAFT TIRES
The life of a tire depends directly on its
storage conditions. Even if manufacturer’s
recommendations are strictly followed, the
lifetime is going to be compromised
depending on how long tires will be stationary
in storage. The stress produced by its own
weight can cause severe damage. A well-built,
automatic-manual, cheap and durable storage
rack will be developed to maximize tires
lifetime.
The above figure shows the final built rack cell. It was designed to carry
up to 3 cells (one above another) and a total of 12 aircraft wheels, each
wheel weights up to 200kg. The wheels will be spinning approximately
3333 00 by rollers located below each tire. The rollers are connected to a
transmission system which can be powered manually or automatically
by a portable drill. A reduction was calculated and simplified in a two
pulley and belt transmission, if there is no available power, it can be
turned manually by its operator. The structure was dimensioned to be
constructed by 30x40x2mm (lower bars) and 30x30x2mm (upper bars)
quadratic profiles of AISI 1020 Steel, which is fairly cheap but enough
to carry everything safely.
To reduce side friction, a spring system was added to adapt the wheel
to a quarter cell space.
An structural analysis was simulated and the results seemed to be fair.
σσ
yy = 33 . 555555 xx ee 77 NN 22 /mm
Factor of Safety: 9.8
Maximum Displacement: 0.382mm
Project Supervision:
Dr. Tushar Dhavale
Project Summary
A research on how to reduce wear of
aircraft wheels when stored in racks has
been accomplished. A storage aircraft
wheel rack was intensely developed with
computer modelling and computer-trials.
The tests showed that the rack will work
at a very low cost and with a versatile
power source.
It was also developed a traceability
program which is capable of multiple
functions being able to store multiple
data from wheels and its characteristics
such as model, location storage dates.
A few restrictions have to be made due
to a not complete prototype which will
be build in the future.
Aim of the Study
A reduced lifetime in aircraft
tires has been detected over
the past decades, a versatile
solution to reduce stress over
the body of a tire when it is not
in activity (storage conditions)
must be created. The aim of
this study is to develop and
produce a simple, low-cost
system which can provide a
longer lifetime to military tires.
In addition to it, a fast and
simple traceability system
should also be developed;
creating a practical
environment which the
operator is allowed to store
the necessary data of each
different wheel.
Common problems caused by improper storage conditions.
Groove Cracking and Rib Undercutting can be seen in the
figure respectively.
Rack Construction
A traceability program was also created. The program itself has a database
capable to store data of each wheel (localization, manufacturer, date and
storage time, wheel number, storage status). It was developed in Python which
is a simple language and the device chosen was a raspberry pi due to its low
cost and efficiency to this operation.
Conclusion
After different assumptions trying to find a numerical solution to the storage
problem, it was observed in the calculations that the storage racks are safe
enough to carry any sized tire of the military aircraft industry. The
transmission system created is very simple and efficient to the operation,
being both manual and automatic, the operator will have no difficult to spin
heavy wheels. The traceability program itself represented a very successful
part of this report. It was well-built and tested, the software responds as it
was ideally predicted.