UWE Bristol Engineering showcase 2015

Rodrigo Bulhões Ribeiro de Sá Dias
BEng Mechanical Engineering
Design and project of a rack for aircraft tyres storage
Introduction
During many years, the desire of fly was just a dream for
humanity. One of the most important invention ever is the
aircraft. Today, thousands of flights are conducted around
the world and it became the easiest way to go from one
place to another. Maybe the most critical item in an
aircraft in terms of security are the tyres .Tyres are critical
items for safety because, in addition to supporting the
weight of the aircraft on the ground, should absorb much
of the shock of the aircraft on the runway, in landing,
acceleration, sudden decelerations and large temperature
variations. At high altitudes, temperatures support can
reach 55 degrees below zero, at high altitude, while
withstand temperatures more than 80 degrees above zero
during landing or over 100 degrees in a rejected take-off
(RTO - Reject Take-off). Therefore, tyres need to be very
well inspected and stored.
Tyres damage and storage
The storage of tyres is the focus of this work. The
organization and the logistic handling with tyres is as
important as the design of the rack and the others
related equipment. The more well maintained the
storage site and the surrounding are, the more easily is
to guarantee a good condition of tyres. New or
retreated tyres and tubes should be stored in dry place,
cool and without direct sunlight. Temperatures should
be between 32°F (0°C) and 85°F (30°C). Fluorescent
lights, electric motors, electric welding equipment,
battery chargers, electric generators and similar should
be taken away from tyre because these equipment
create ozone and it has a bad effect on rubber. Another
deteriorating effect on rubber is the contact with oil,
gasoline, jet fuel, hydraulic fluids or similar
hydrocarbons. A special attention should be taken for
not lay tyres on floor in which these contaminants can
be in contact
For storage aircrafts, it is important to protect the tyres
with metallic covers and move the plane often, to avoid
the "flattening" of the tread.
The project
It was designed two types of racks, each one for a
range of tyres. The idea was to create a concept that
could store 4 tyres, but two more structures can be
stacked, totalizing 12 wheels.
To the structural analysis, just the largest rack was
considered. This was the critical situation
because in this case the structure is subject to
higher pressures and it supports more weight.
Once the structure was dimensioned with profiles
of 30x40x2mm in the most critical area and with
profiles of 30x30x2mm in the trusses, the
boundary conditions for the analysis can be
determined. The figure below shows the stress
distribution considering stacked racks and
diagonal trusses.
The same analysis was done with the same
type of rack but using vertical trusses
instead of diagonal trusses to investigate
which design is more reliable.
Maximum stress in this new structure was
3.567 × 10 7 N/m², which results in a security
factor of approximately 9.8, and it allows to
reduce the thickness of the profiles.
Furthermore, taking in account the
deformations, the maximum displacement
was 0.382 mm, about 10 times lower than
using diagonal trusses. Therefore, the results
were very satisfactory.
Traceability
To help in documentation and tyre traceability,
it was developed a computer program to be
utilized by the employers responsible to
maintenance and transport of the tyres. . The
program was developed in Python and it
allows to follow operations such as removal,
storage and database of the tires just typing
the tyre serial number.
Project Supervisor
Tushar Dhavale
Project summary
An investigation has been accomplished to develop a
new alternative of a rack to store aircrafts wheels.
This new design is necessary because there are some
problems related to lay tyres on floor during too
many time causing distortion and damage. Therefore,
what is propose in this work is a rack where the tyre
lay on rolls that are rotated by a drill or a crank.
Traceability is another important point and it is
purposed to use a Python programming and a
raspberry pi device. This allows the mechanic or
another responsible, to know where the tyre is as
well in which rack it is and all the details about
inspection.
Project Objectives
The main aim of this project is to develop a new
design of rack to store aircraft tyres. It will be
achieved through the realization of several subaims.
Some of them are itemised below.
1. Study all available literature concerning to
tyres characteristics, since manufacturing until
storage and maintenance.
2. Build a 3D model of the rack and calculate the
specifications of the design components.
3. Simulate different designs to choose the most
reliable and analyse stress and deformation.
4. Programing the traceability system.
Project Conclusion
A new design of a rack to store tyres was developed.
Each one of the aims were achieved to project the
system. The rack structure was analysed using the
SolidWorks tool and it is secure for the loads applied.
The first structure, with the diagonal truss, has
greater value of deformation when compared with
the second structure. Therefore, this project was
successfully in terms of the designs, and the selection
of the components. The reduction system is what
makes possible to turn the tyres using a drill or a
crank. It is not necessary to do this using human force
and this represents comfort to the operator and more
security, reducing accidents. The traceability
development is another achievement of this project.
It is a simple, low cost and efficient system that
allows organization and a better management.