This is an example of my work over the years. I have examples of my design work, cad drawings, and technical writing.

1. NC A&T STATE UNIVERSITY
College of Engineering
PORTFOLIO
Amber Williams _______________

2. Table of Content
Contents
Preface......................................................................................................................................................................3
Resume.....................................................................................................................................................................4
Biweekly..................................................................................................................................................................6
Calculations............................................................................................................................................................10
DESIGNS...............................................................................................................................................................11
File Sharing Program.............................................................................................................................................28
Picture of my Work................................................................................................................................................29

3. Preface
This portfolio is an organized collection of goal-driven artifacts of my professional
growth and achieved competence over the past five years. I am a senior Mechanical
Engineering student studying at North Carolina A&T State University. During my course of
study, I have learned problem solving techniques, integration of theories into real life
applications, and how to work in a group environment. As my journey ends at North Carolina
A&T State University, I look forward to taking what I have learned into the corporate world to
come up with new and innovative ideas for the global economy.
I am dedicating the portfolio to my youngest sister who passed away on October 19, 2010
after a short battle with Lupus. Through her illness she struggled daily with chronic pain to
complete her first year of college on a full academic scholarship at Chowan University. It was
her determination to succeed that gave me the strength and motivation I needed to complete this
course to the end. Her quiet spirit will never be forgotten, and her smile will always be a
reminder of pushing forward to succeed regardless of circumstances. Feel free to browse and
contact me with any questions.

4. Resume
Amber Michelle Williams
Security Clearance: Top Secret SSBI (Inactive)
31 Woodstream Lane. Apt C Greensboro 27410
Phone number: (757) 609-1148 Email: awilliams109@gmail.com
OBJECTIVE To obtain a challenging and rewarding position in mechanical engineering that best uses
my experiences, education, and research skills, with an opportunity for personal and
professional development.
SPECIAL SKILLS
• Top Secret Security Clearance
• Solid Works
• Matlab
• Technical Writing
• Microsoft Office 2014
• Radiation Con Worker 1
• General Education Radiation Training
• Laser Safety Training
• Oxygen Deficiency Training
• Ladder Safety Training
• General Access RWP training
• Lathe Machining (Intermediate)
• Milling machining (Intermediate)
EDUCATION North Carolina Agricultural and Technical State University
M.S Mechanical Engineering, May 2015
B.S. Mechanical Engineering, May. 2013
Certificate in Waste Management, May 2013
Certificate in Hazmat Training May 2013
EXPERIENCE
NC FIRST Robotics Engineering Project Manager
Greensboro, NC August 2013- Present
• Developed the North Carolina Mobile Machine Shop
• Conducted Solidworks Seminar
• Managed 47 teams across the state of North Carolina
• Attended Several Leadership Conferences for professional development
• Managed For Inspiration and Recognition in Science and Technology (FIRST) in the
state of North Carolina efficiently
• Develop online seminars and curriculum; prepared presentations and data analysis to
expand (FIRST) across the state of North Carolina using Microsoft word, PowerPoint,
and Excel to make North Carolina a competitive state in STEM education
Department Of Energy Engineering Technician
Newport News, VA May 2012- August 2012
• Designed a Pressure Vessel Relief System after glass shattered into one of the
contractor’s eyes.

5. • Managed the contractors of the Electronic Free Laser
• Worked on the Department of Energy Budget
• Over saw government contractors to make sure they were in compliance with the contract
set forth by the Federal Government, which included but not limited to safety, budget,
and efficiency
• Used Microsoft excel and Matlab to Performed routine data analysis, statistical
compilations, and narrative presentations for the Department of Energy
Waste Management Institute Researcher/Office Assistant
Greensboro, NC Fall 2010-December 2011
• Researched, collected data in Microsoft excel, and presented data on water treatment in
Nigeria so they can have better water treatment and irrigation systems
• Facilitated the environmental programs at North Carolina A&T State University which
lead to a Greener Campus.
Lead Rear Suspension Engineer of the 2011 Aggie Racing Team
Greensboro, NC Fall 2010-May 2011
• Designed, analyzed, and created in Solidworks the rear suspension of the 2011 Aggie
Racing Baja Car
• Presented the sales presentation at competition and put together a business portfolio for
the team
• Budgeted the Bill of Materials for the project and had to present the car for the Society of
Automotive SAE Judges
North Carolina A&T Composite Material Research Center
Greensboro, NC November 2009- May 2010
• Prepared the technical documents and tracking project schedules to conduct a one year
research project on the benefits and the procedures of Electrospinning as well as ensured
the proper functionality of the composite structures, when exposed to different situations
and loads.
ACTIVITIES
National Society of Black Engineers
Society of Women Engineers
American Society of Mechanical Engineering
2nd
Vice President of the Virginia Conference Young People Department
North Carolina Technology Association
North Carolina Symposium of Non-Profits
AWARDS
Broad Prize Scholarship
Gear Up/ Access Scholarship
NASA-Center for Aviation Scholarship
REFERENCES Furnished Upon Request

6. Biweekly
Date of Bi-Weekly Report: 2/3/2011
Approximate Value Added Hours per week: 30
Technical Contributions: Made first tab for the chassis, made the cut for the firewall
Administrative Contributions: Design Report, wrote a list of items to go into the BOM,
started the posters
Planned objectives to be completed for next two weeks: Finish posters and try to learn to
weld
Lessons Learned: How to use the plasma cutter, created the poster for the BOM
Baja SAE

7. Date of Bi-Weekly Report: February 17, 2011
Approximate Value Added Hours: 25 per week
Technical Contributions: Brake Calculations and the jig plate
Administrative Contributions: overall design poster
Planned objectives to be completed for next two weeks: Drive train, Suspension,
Ergonomics, and Chassis posters
Lessons Learned: How to do brake calculation, and help in design poster.
Baja SAE

8. Name: Amber Williams
Date of Bi-Weekly Report: 3/3/11
Technical Contributions: Side/Floor Panels
Planned objectives to be completed for next two weeks:
• Finish the Design Paper for the Kansas Event
• Have a good rough draft for poster
Lessons Learned: N/A
Baja SAE

9. Date of Bi-Weekly Report: 3/17/2011
Approximate Value Added Hours: 25-30 hours weekly
(Most of the time is spent at night)
Technical Contributions:
• Pressure Mount Switch
• Floor Panel
• Numbers for Car
Administrative Contributions:
• Posters
• Revised Paper
• Set up file Sharing
Planned objectives to be completed for next two weeks:
I plan to get the decals/posters ordered; paper finalized, and tries to find little parts to contribute
to the car getting done.
Lessons Learned: Created tab to keep pressure mount switch in place.
Baja SAE

10. Calculations

11. DESIGNS
The team this year decided to build a modified four link suspension. A modified four link made the rear
suspension of the car stronger, redesigned the rear arms from previous years and put them into compression and
tension, meaning the arm were less likely to break.
Constraints set by the team
Wheel Base
Track Width
From these constraints, we were able to find the camber curve we wanted. Solidworks was used to analyze these
Using the software like Solidworks, I was able to see how the car would look at full bump, ride height, and
droop.
This year’s camber curves were as followed
• Full bump -5.125°,
• Ride height it is 0°
• Full droop camber +1.0°.
The Pythagorean Theorem
This was used to make sure the triangulation was correct for the rear suspension.

14. Reports
For our senior project, technical writing is just as important as fabrication of the car. For the event the car was
entered in, a design report had to be submitted. The design report explained how the car worked, and why the
team chose the design it did. Below is an example of one of the design report. The technical information and
subcomponents were given to Amber Iciano, Earl McDermott and myself to go through and make the necessary
corrections.

15. Car Number 068
North Carolina A&T State Univ. Baja SAE Design Report
Prepared by
Amber Williams
Copyright © 2007 SAE International
ABSTRACT
North Carolina A&T State University’s SAE Baja
car for the 2011 season has developed many new
design and technical aspects. Aggie Racing will
compete with teams from around the world in
design, static, and dynamic events with rules set
forth by SAE. The team was given a Briggs and
Stratton 7.46 KW engine as the foundation of the
car and under certain constraints designed a fully
functional vehicle. By increasing success, this
year’s team is looking to compete with the top
universities from around the world and win in the
various events. Aggie Racing strives to lead in the
innovation of new ideas, development, and
manufacturing of off-rode vehicles to become a
premier Baja SAE competitor.
INTRODUCTION
The objective of this competition is to simulate a
real-world engineering design project and its
related challenges to build a prototype of a
durable, single seat, off-road recreational
vehicle. The vehicle should aspire to market-
leading performance in terms of speed, handling,
ride, and ruggedness over rough terrain for the
off-road enthusiast. This product will be
proposed to a fictitious company with intentions
of producing a product line of 4,000 vehicles per
year for the above application.
Aggie Racing’s main design objectives are safety,
durability, and performance. Through Finite
Element Analysis (FEA) and the concepts learned
throughout collegiate course work, the team was
able to surpass expectations. There was an
estimated 15% overall weight reduction from 2010
according to actual evaluation.
All systems included integration of off the shelf
parts with in-house manufactured parts as well.
All parts and designed systems undergo a
concise analysis which includes our design and
purchase proposals. The purpose of these
proposals is to rate each design or purchase
option so that an intelligent and well informed
decision can be made to determine whether the
part complies with our demands. Proposals must
include design matrices and research data as well
as confirmation of SAE rules compliance.
Design decisions were subject to change due to
pending testing results and production time.
CHASSIS DESIGN
Being generally satisfied with the overall shape and size
of 2009 and 2010 chassis, this year’s focus was on
reducing unnecessary weight while improving the
structural integrity and rigidity. This goal was achieved
by triangulation coupled with lighter materials, resulting
in an ideal platform for all subsystems of the vehicle.
Figure 1 shows the different tubing sizes used in the
design of the chassis. Red represents 3.175cm x
0.1651cm (1.25”x.065”), green represents 2.54cm x
0.0889cm (1”x.035”), and yellow represents 2.54cm x
0.1245cm (1”x049”). The changes in tubing dimensions
resulted in an 18% reduction in weight from the previous
season’s chassis. The chassis is designed to
accommodate all of these subsystems while providing a
safe envelope for the driver.

16. Figure 1: Chassis Tubing Members
SAFETY – During the design process, Aggie Racing
made it a point to incorporate safety design features into
the car. Baja SAE holds safety of the chassis to the
upmost importance; therefore, most the rules are related
to the chassis. The critical tubing material must meet a
standard guideline set by SAE. Side Impact Members
(SIM) were created with offset bends that flare away
from the driver to ensure proper clearance incase the car
rolls. In order to keep the driver fully restrained to the
cockpit, a five point harness is required.
Figure 2: Chassis
MATERIALS – In the rules a standard tubing size is
specified for the roll cage. Members must be made of a
material with a bending stiffness and a bending strength
equal to that of 1018 steel, with a size criteria of .254cm
x 0.3048cm (1”x.120”). According to these restraints
and performing calculations, the minimum bending
stiffness of 20.71 MN*m2
(3,002.5 lb*in2
) is needed.
E –the modulus of elasticity
I – the second moment of area for
the cross section
Sy –the yield strength
c - the distance from the neutral axis
to the extreme fiber
Figure 3: Bending Stiffness vs. the wall thickness
Table 1: Tubing Alternative Comparison
Material 1018 Steel 4130 Steel
Outer Diameter (cm) 2.54 3.175
Wall thickness (cm) 0.3048 0.1651
Weight (N/m) 1.53 1.11
Ultimate Strength(MPa) 415.6 1,110
Bending Stiffness (kN*m2
) 2371 3094
Bending Strength(N*m) 4256.7 5844.9
Analysis –Forces are based on a 182.88 cm (72”)
drop on one wheel with a 113.40 kg (250 lb) driver
and a 192.78 kg (425 lb) car. These forces were
applied at the shock locations with a magnitude of
573.79 kg (1264.99 lb), or 1.8 G-force. The results
showed possible bending at the rear shock mount,
which was immediately remedied by placing a
2.54cm x .1254cm (1”x0.049”) chromoly tubing for
mount support. The FEA showed a maximum
stress concentration of 135.41 MPa (19,640 psi) and
the material’s yield strength of 434.37 MPa (63,000
psi). Failure is unlikely to occur given a factor of
safety of 5.7 .
Figure 4: Finite Element Analysis performed on the
chassis
SUSPENSION
The purpose of the suspension is to absorb imperfections in
the road while providing a safe and comfortable ride. Without
a well-designed suspension, the vibrations would be
transferred directly to the car and the driver. A strong
suspension system provides good handling over multiple
terrains and keeps the wheels planted for turning and applying
power to the ground.

17. The 2011 car uses a traditional dual arm based front
suspension. The weight, cost, and ride quality have
improved while keeping reliability and safety as a
priority. A-arm and upright shape and materials, tire and
wheel selections, and smaller brake components have
significantly lightened the suspension’s un-sprung mass
by approximately 4.082 kg (9 lb) per corner in the front.
The vehicle performance was significantly improved by
paying closer attention to suspension geometry and the
outside forces that affect performance. The camber
curves from last year’s car were satisfactory and only
needed slight adjustment. Rake was introduced into the
chassis last year and was kept in this year’s design.
Rake creates more front end ground clearance and
automatically generates caster for improved dynamic
stability.
FRONT SUSPENSION – The front suspension uses
an unequal length, non-parallel dual a-arm based
system.
Table 2: Critical Front Suspension
Camber Gain 7.69 ͦ
Caster 12.5 ͦ
King Pin 1.03 ͦ
Rake Angle 12.5 ͦ
Static Camber 1.69 ͦ
Camber– By balancing the upper and lower pick up
points on the chassis and uprights, Camber gain is
incorporated to provide maximum tire contact with the
ground at all times. This ensures the highest
performance from the car. The distance between the roll
center and the center of gravity were kept at a minimum
to prevent rollover during cornering. In order to achieve
optimum camber changes, the upper and lower control
arms are 36.58cm (14.4”) and 42.44cm (16.71”),
respectively. With the incorporation of hiems lining up
with the upright, the A-arms are designed with no bends
for ease of manufacturing. The length of the control arms
allow for a total travel of 25.4cm (10”) with 17.78cm (7”)
of jounce and 7.62cm (3”) in rebound. A camber gain of
-7.69° in bump was designed to assist in tire contact
under aggressive cornering. The camber recovery is
76.9 % and the static camber remains near 1.69° , while
moving to +0.2° in jounce from jounce from static.
Figure 5: Front Suspension Assembly
Uprights – After the camber angle was calculated, the
control arms and steering radius were determined
allowing for the pickup points for the upright to be found.
The front upright is 13.334cm (5.25”) tall and the king pin
is 2.62cm (1.03”). The total weight is 0.5216 kg (1.15 lb)
compared to the 0.9208 kg (2.03 lb) upright in the 2010
vehicle. The material chosen for the front uprights was
Aluminum 6061-T6 due to its light weight, affordability,
and attainability.
Analysis – A Finite Element Analysis was performed on
the front suspension components in order to ensure
safety, while minimizing failure. FEA also provided a
graphical image of the best places for design
improvement and weight reduction. With a factor of
safety of 1.63 and using a force of 1131.98 kg (2,500 lb)
on the steering arm, the upright would be adequate
under extreme loading.
Figure 6: FEA of front upright
Wheel Hubs & Spindles – The hub was designed to be
compact and lightweight, weighing in at .39 kg (0.86 lb),
this is a 47.5% reduction in weight over last year’s
design. The material chosen for this component was
Aluminum 6061-T6.
Figure 7: 2010 Designed Hub & Spindle
In order to connect the hub to the upright, a spindle was
designed which is connected by a slip fit on the two
bearings and a press fit in the upright. One castle nut is
used to clamp the spindle to the upright and one also
holds the hub on the spindle. The bearings were chosen
based on extensive calculations for deep groove ball
bearings, with the understanding that they will be
changed after 50 hours of operation. The bearings
selected were capable of running at 48.28 km/hr (30
mi/hr). These bearings are double shielded to keep
larger debris out. The spindle used in 2011 is 1.27 cm

18. (.5”) shorter, creating a shorter moment arm and
reducing the chances of failure seen in 2009.
Figure 8: Failed 2009 spindle
REAR SUSPENSION
The main purpose of rear suspension is to work in
conjunction with front suspension, keep the car
stable and keep the tires in contact with the ground
for good power delivery. The 2011 team decide to
change from using A-arms to a modified four link
suspension. One of the advantages of this design is
the members used in the structure are taken out of
bending and put more into tension and compression.
The distribution load will relocate to a more
centralized location in the chassis. This design
offers a form of roll steer which helps with weight
placement. The proposed design has approximately
0.635 cm (.25”) of toe out in droop and 1.905 cm
(.75”) toe out in bump. The designed rear
suspension is shown in Figure 8.
Figure 9: Rear Suspension Setup
Camber –The camber curve ranges for 2010 were
inspected in conjunction with pictures from testing
and changes were made accordingly. Optimum
camber gain is half of body roll, from pictures it
was determined that the body rolls ~10°. A 51.25
% camber recovery was used to design for the
amount of camber needed. This keeps the wheel
and tire vertical at all times to prevent rollover.
Based off of this information the optimum camber
curve was determined. At bump the wheel is at
-
5.125°, at static ride the wheel is flat and in droop
the wheel is +1.0°. The CAD model is shown in
Figure 10.
Figure 10: Rear Camber
Analysis – Spreadsheets were created to determine the
optimum placement of the shock on the trailing arm to
minimize deformation or bending of the arm. After hand
calculations were completed and the system was
modeled, Finite Element Analysis was performed on the
rear arm to double check the calculations. For the FEA
study, the entire load is used. Using the same
situational loading as the max test load, the stress, strain
and displacement plots gave an approximation of the
magnitude and location of the high stress/strain in the
design. All arms used AISI 4130 chromoly steel tubing,
which posted factor of safety of 1.90. Again, these
results are more than favorable and demonstrate the
safety and reliability of the design.
The stress, strain, and displacement plots shown in
Figure 11 provide an approximation of the magnitude
and locations of the high stress/strain in the design. This
is important in the design process since it gives an idea
of where weight can be reduced by removing excess
material. It can also show areas where structural
reinforcements may be required to better protect the
design. The original design of the arm had only two
tubes with no side walls between them. When FEA was
completed on the first iteration of the design the arms
went into plastic deformation. The results from this
study approximated a maximum stress of 193.7 Mpa
(28.1ksi). Comparing this to the yield strength of 4130
Chromoly 434.4 Mpa (63.1ksi) gives a factor of safety of
2.36. These results are more than favorable and
demonstrate the safety and reliability of the design.

19. Figure 21: FEA performed on the trailing arm
Camber Arms – The camber arms keep the wheels at
the proper track width and provide the path necessary
for the camber curve desired. The only load felt by these
arms are the lateral forces felt while turning. Since the
configuration of these arms has them in tension and
compression, they were not considered critical load
carrying members.
Shocks
Aggie Racing decided to go back to running coil over
shocks versus air shocks that have been used in the
past. A dual spring Works coil over offers the
performance needed while retaining a low cost. The coil
overs are height adjustable via the spring perches that
are threaded onto the shock body. Although the air
shocks are lighter and cheaper, they do not offer any
rebound. This was the main concern when choosing
shocks for this year’s car. With the adjustability of the
system, this year’s car can be elevated above the ride
height so that when the driver sits in the car, it sinks to
ride height.
Tires and Wheels
TIRES - For the 2011 Baja car, 55.9cm x 17.8cm x
25.4cm (22”x7”x10”) size ITP Hole Shot XCR tires are
being utilized on the front, while ITP Mud Lite SP tires
are being used for the rear. The ITP Hole Shot is a
directional tire which has angled shoulder knobs for a
better bite during cornering on the track. The ITP Mud
Lite SP is also a directional tire but specializes in the
treads ability to be self-cleaning. This characteristic is
ideal for rear tires, allowing a consistent transfer of
power from the drivetrain to the ground throughout the
duration of the race.
WHEELS – The ITP T-9 Pro-Series wheels chosen for
this year’s Baja car are approximately 2.268kg (5 lb) per
wheel lighter than the wheels used in 2010. This is a
drastic reduction in the unsprung weight of the vehicle,
allowing for a better performing suspension. The wheels
are double-rolled for an increase in strength and are also
less resistant to bending during an impact.
STEERING
The steering design focused on two main areas: weight
reduction of the entire assembly and improvement the
steering response. The Aggie Racing team decided to
most manufacture the steering components to get the
exact specifications needed.
Figure 32: Rack & Pinion
ACKERMANN GEOMETRY – To design for a sharper
turning angle and better maneuverability, Ackermann
geometry was used due to the low acceleration and
speeds of the Baja vehicle. Aggie Racing is
incorporating an Ackermann angle of 40° with a
resulting 304.8cm (120”) turning radius to allow the
vehicle to easily maneuver around sharp corners.
Figure 43: Ackermann geometry
BUMPSTEER – Solidworks was solely used to analyze
bump steer for the 2011 Baja car. The location of the tie
rod pick up point was determined to be 10.92 cm (4.3”)
to the rear of the center of wheel and 33.02 cm (13”)
from the bottom of the 55.88 cm (22”) tire. The best
location for the steering rack was found to be 10.16 cm
(4”) behind the wheel center.
TOE – In order to enhance the steering performance and
increase the ability of the vehicle to go into a turn, toe in
was set to 1.17° out on the front tires, minimizing the
prospect of an undesired steering projection.
RACK & PINION – The use of a 16 tooth pinion with a
25.4cm (1”) diametral pitch was chosen to provide
quicker steering by allowing more movement along the
rack per revolution, resulting in a steering ratio of
approximately 12:1. The steering rack is made of 1045
steel, which allows for the rack to endure bending loads
without plastic deformation. The lock to lock length

20. permits the pinion to travel 3.81 cm (1.5”) from the
center position to the end. Coupled with the Ackermann
geometry, the inside wheel is allowed to turn slightly
more than 41° at its maximum.
Analysis – Finite Element Analysis (FEA) was performed
to support the selection of 1045 steel. The study
subjected the steering rack to bending loads from the tie
rod and transmission loads from the pinion. By applying
a force of 226.80 kg (500 lb), a factor of safety of 2.5
was determined. This shows an adequate selection of
material, which is unlikely to fail.
Figure 54: FEA performed on the rack
DRIVETRAIN
The drivetrain for the 2011 car is similar to what A&T has
run in the past. It is comprised of a CVT driving a chain
reduction box that uses 1.27 cm (.5”) aluminum side
plates and a polymer center section for spacing and
safety guarding. Inside the housing is a double
reduction chain drive system. The aluminum and
polymer lowers the weight and adds to the aesthetics of
the rear of the car. This type of system was chosen for
its reliability, efficiency, and reduced cost. This type of
system has proven these factors in 2009 and 2010. The
internals and partial externals can be seen in the Figure
15.
Continuously Variable Transmission (CVT)
A properly tuned CVT allows the engine to stay at
optimum torque and power rpm range for quicker
acceleration. This is done by the pulleys on the CVT
being able to automatically change diameters; therefore,
changing the ratios between the pulleys. A Gaged
Engineering GX-9 was chosen this year for its
performance and reliability. The larger range of ratios of
this CVT allows us to run a lower reduction ratio in the
box while keeping our top speed the same. This gives
us more low-end torque than 2010.
Sprocket Box
The sprocket box has been designed to be lighter and
stronger than previous years. The polymer center
section and light sprockets keep the weight low. A
stronger #428 chain increases the strength of the overall
design. This chain is the same size as the #40 used last
year, but it is 35% stronger. A 10.028:1 reduction ratio
gives us ample output torque while retaining a
reasonable top speed. Below are some of the equations
used to determine the ratios and the torque in each
shaft:
The ratio per sprocket set had to be calculated first using
the following equation:
Then the overall sprocket ratio was computed with the
following equation:
Table 3: Sprocket Box Calculation
Sprocket # of teeth
S1: 12
S2: 38
S3: 12
S4: 38
Sprocket
Ratio
10.028
Set Ratio 3.167
Shaft Torques (Newton-Meter)
Shaft 1: 78.64
Shaft 2: 249.06
Shaft 3: 788.54
Using F=2T/D
Force
(Newton)
F1=F2: 3205.17
F3=F4: 10149.73
Table 2 contains the proposed sprockets used for the
reduction box for 2011. After the desired sprocket is
established, the sprocket ratio as well as the torque is
found. Forces on the shaft can then be determined. This
information helps us to determine how strong the shafts
need to be for FEA testing.

21. Figure 15: Chain Reduction Box
Shaft Material Analysis
All three shafts will be 4140 Pre-heat Treated Chromoly
Steel. This material is slightly higher in cost than mild
steel. However, its strength more than makes up for the
cost increase over the mild steel. Below are sample
calculations for shaft 1 utilizing the ASME Elliptic design
equations for power transmission shafts.
Using 4140 Pre-heat Treated Steel,
Sut=655 Mpa Sy=413.7 Mpa
Dimensions of Shaft (centimeters)
( Drawing is not to scale)
The specimen endurance limit was calculated for
steel:
Then the modifying factors were applied to obtain
the true endurance limit for the shaft:
Mpa
Then the appropriate diameter for the critical
section is estimated using a factor of safety of 1.5
(n=1.5):
Using the ASME Elliptic Code:
From the above values, q and qshear are found using
the notch radius:
From the above values, Kt, Kf, and Kfs are found:
The diameter is then found using the ASME Code:
The above calculations determine the diameter of
the shaft by the fatigue safety factor.
BRAKING SYSTEM
When focusing on braking, several factors were
considered: weight, efficiency, reliability and cost.
The braking setup of 2010 worked, however with
the smaller wheel that was chosen for this year a
new setup was required. This year’s car
incorporated the same braking scheme with
emphasis on lightening the components where
possible and using less expensive equipment.
To approximate the braking torque required, a
simple work-energy balance calculation was
performed. For a 192.78kg (425 lb) car with a
113.40kg (250 lb) driver, the required braking
14.48
2.223
0.1699
2.53
3.71
1.915 1.699
1.676
2.535

22. torque needed was approximately 413.13 N-m
(3,656.5 lb-in) in the front and 275.42 N-m
(2,437.64 lb-in). Using an Excel spread sheet, the
hand calculations were verified. The desired setup
produced a very respectable 266.31 N-m (2,357.06
lb-in) of braking torque in the front at each wheel
and 349.58 N-m (3,094 lb-in) in the rear. This
yielded a factor of safety of 1.289 in the front and
1.269 in the rear. Using the setup’s specifications,
components were selected and manufactured based
on cost, availability, and manufacturability.
Front Braking
In order to achieve the proper ratio the front braking
is shared through both wheels using an 18.16cm
(7.125”) rotor with single piston MCP Kart caliper.
These have a 2.54cm (1”) bore. This setup is shown
in Figure 16.
Rear Braking
The rear uses a single in-board rotor of 20.32cm
(8”) diameter with a dual piston caliper of 2.54cm
(1”) bore also connected to the same brake pedal
assembly. Incorporated into the rear system is a
single rotor just outside the sprocket reduction box
shown below in Figure 15. Incorporating the rotor
in with the sprocket reduction box assists in
reducing un-sprung mass. This integration also
allows for easy access and assembly. Knowing that
the single rear rotor was factored into the brake
system design, the added cost of additional purchase
and/or manufacture was avoided.
Figure 66: Gear Box with Rear Brake Assembly and Front
Caliper Assembly
Pedal Assembly
The pedal assembly chosen this year is a reverse
swing mount dual reservoir setup. This allows us to
cater the needed pressures for the front and rear
brakes separately. This pedal assembly has the
option of using a bias bar that allows further
adjustment for fine tuning the braking setup.
CONCLUSION
The goals of 2011 Aggie Racing team were to
design a safe, affordable, lightweight vehicle to
appeal to the off-road enthusiasts. The team
designed for the worst case scenario, without over
designing the car. In order to achieve these goals,
the team designed all major system and components
based previous team experiences, on testing
performance, and engineering calculations. The
2011 Baja successfully improved Aggie Racing
program by stepping out its comfort zone and
making major modifications to the 2011 Baja car.
With innovative ideas for the 2011 car, Aggie
racing is a premier Baja SAE competitor.
REFERENCES
1. Nisbett, R.G. (2008). Shigley’s Engineering
Design.
New York, NY, USA: McGraw-Hill Inc.
2. Gillespie, T. D. (1992). Fundamentals of
Vehicle Dynamics. Warrendale, PA, USA:
Society of
Automotive Engineers Inc.
3.
http://mathworld.wolfram.com/AreaMomentofI
ner
tia.html
4. Milliken, W. F. (1995). Race Car Vehicle
Dynamics. Warrendale, PA, USA: Society
of
Automotive Engineers Inc.
6. Smith, C. (1984). Engineer to Win. St. Paul,
MN,
USA: Motorbooks.
7. Smith, C. (1975). Prepare To Win. Berkeley,
CA,
USA: Aero Publishers Inc.

25. These are the posters created for the design competition. I chose the layout, information as well
as the pertinent pictures on the posters. Earl McDermott and Amber Iciano helped with grammar
as well giving input to make the posters standout.

27. Sponsors are a big reason why Aggie Racing is a big success. Below is an example more of
Technical Writing skills.
March 31, 2011
NCAT Bookstore
1601 E. Market St.
Dear Cynthia Beasley,
I am writing you on behalf of the North Carolina A&T State University’s Aggie Racing Team.
Aggie Racing is an organization started to compete in the Society of Automotive Engineering
competitions. Our mission is to strive to lead in the innovation of new ideas, development, and
manufacturing of off-rode vehicles to become a premier Baja SAE competitor.
On April 14, 2011, Aggie racing will be attending their first SAE event for the year in
Birmingham, AL. Your donation of A&T stickers and logos will help promote A&T’s name
throughout the various competitions we attend. We would greatly appreciate a donation of two of
your A&T Bulldog stickers, 2 NCAT stickers, and 4 small A&T stickers. In return for your
generosity, we will send you pictures of the finished product.
Thank you for considering our request. If you have any questions or need further information,
please feel free to contact me. I will follow up with a phone call in the next couple of days.
Sincerely,
Amber Williams
(757) 609-1213
awilliams109@gmail.com

28. File Sharing Program
I was one of the main creators in our file sharing program for the 2011 BAJA SAE team. The
information is stored online so anyone on the team can access it from any computer. This allows
the team to communicate without being face to face. Below are a few screen shots of the
program at work
• Dropbox for Teams combines the synchronization, sharing, and security features of
traditional Dropbox with new administrative and group capabilities that make it perfect
for businesses, organizations, and groups.
• Storage quotas are shared by the team rather than bound to individual accounts. Now the
team can share one large pool of storage instead of having to manage the storage
limitations of individual accounts. Shared folders only take up the team's storage quota
rather than space in each individual account.
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29. Picture of my Work
I had the privilege to learn to use the Tig welder, the mill, the lathe, the plasma cutter, and the
electrical shears. Below are examples of the work I did with each of the machines listed above.
I used the electrical Shear to cut out the numbers for this years car.
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30. I used the drill to drill holes in the chassis and I used the electrical Shears.
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31. The Transponder Mount was mad from 1/8’’ Steel and I used the plasma cutter to cut out the square.
In order to do safety wiring, I had to drill a small whole in the side of the bolts using the lathe.
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32. I used the plasma cutter to cut through .275 ins of steel to make the tabs
http://forums.bajasae.net/forum/free-sla-suspension-kinematics-program_topic688.html
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