NC A&T STATE UNIVERSITY

College of Engineering

PORTFOLIO

Amber Williams _______________

Table of Content

ContentsPreface.....................................................................................................................................................................3Resume....................................................................................................................................................................4Biweekly..................................................................................................................................................................6Calculations...........................................................................................................................................................10DESIGNS..............................................................................................................................................................11File Sharing Program.............................................................................................................................................29Picture of my Work...............................................................................................................................................30

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.

ResumeAmber 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 2015B.S. Mechanical Engineering, May. 2013 Certificate in Waste Management, May 2013Certificate in Hazmat Training May 2013

EXPERIENCENC FIRST Robotics Engineering Project ManagerGreensboro, 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 ex-

pand (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 TechnicianNewport News, VA May 2012- August 2012

Designed a Pressure Vessel Relief System after glass shattered into one of the contrac-tor’s eyes.

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 compila-tions, 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 TeamGreensboro, 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 CenterGreensboro, 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.

ACTIVITIESNational Society of Black EngineersSociety of Women EngineersAmerican Society of Mechanical Engineering2nd Vice President of the Virginia Conference Young People DepartmentNorth Carolina Technology AssociationNorth Carolina Symposium of Non-Profits

AWARDSBroad Prize ScholarshipGear Up/ Access ScholarshipNASA-Center for Aviation Scholarship

REFERENCES Furnished Upon Request

Biweekly

Date of Bi-Weekly Report: 2/3/2011Approximate 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

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

Name: Amber WilliamsDate of Bi-Weekly Report: 3/3/11Technical 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

Date of Bi-Weekly Report: 3/17/2011Approximate 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

Calculations

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 BaseTrack 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 TheoremThis was used to make sure the triangulation was correct for the rear suspension.

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.

Car Number 068

North Carolina A&T State Univ. Baja SAE Design Report

Prepared by

Amber Williams

Copyright © 2007 SAE International

ABSTRACTNorth 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.

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 elasticityI – 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 SteelOuter Diameter (cm) 2.54 3.175Wall thickness (cm) 0.3048 0.1651Weight (N/m) 1.53 1.11Ultimate Strength(MPa) 415.6 1,110Bending Stiffness (kN*m2) 2371 3094Bending 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.

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 MCaster 12.5 M

King Pin 1.03 MRake Angle 12.5 M

Static Camber 1.69 M

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 (.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.

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 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 teethS1: 12S2: 38S3: 12S4: 38

Sprocket Ratio 10.028Set Ratio 3.167

Shaft Torques (Newton-Meter)Shaft 1: 78.64Shaft 2: 249.06Shaft 3: 788.54

Using F=2T/D Force (Newton)F1=F2: 3205.17F3=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.

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 MpaDimensions 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:

14.48

2.223

0.1699

2.53

3.71

1.915 1.699

1.676

2.535

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 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 BrakingIn 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 AssemblyThe 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 ofAutomotive Engineers Inc.

3. http://mathworld.wolfram.com/AreaMomentofIner

tia.html4. 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.

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.

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 Bookstore1601 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) 609-1213awilliams109@gmail.com

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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Picture of my WorkI 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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I used the drill to drill holes in the chassis and I used the electrical Shears.

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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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I used the plasma cutter to cut through .275 ins of steel to make the tabshttp://forums.bajasae.net/forum/free-sla-suspension-kinematics-program_topic688.html

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