2017 Baja SAE Competition

MECT 4276 – Fall 2016

Senior Design I – Report I

November 8, 2016

Keith Hernandez

Team Lead

Enrique DeLeon

Mechanical Lead

Manjula Hodekar

Design Lead

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Table of Contents

Introduction 3

Team Objective 3

Deliverables 3

History 4

Event Categories 5

Dynamic Events 5

Static Event 6

Previous Winners 7

Winning Strategy 7

Major Components 8

Chassis 8

Suspension 10

Engine 13

Drivetrain 13

Steering 14

Project Management 16

Budget 16

Timeline 17

Work Breakdown Structure 17

Risk Matrix 18

References 19

Appendix 21

Timeline 22

Gantt Chart 23

Sponsorship Brochure 24

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Introduction

The Baja SAE Competition is one of the design series offered by the Society of Automotive

Engineers (SAE) that University students from around the world can compete in. University

students are required to design and fabricate a high performance off road vehicle. The

competition is a real world scenario that lets students demonstrate their knowledge in the design

and fabrication of a dynamic mechanism. The Baja SAE Competition has a long list of rules and

regulations to ensure the safety of all participants however students are allowed to use creative

and critical thinking to design their vehicle in an innovative fashion. The main focus of the Baja

SAE challenge is to promote teamwork and project management skills between team members.

These qualities become a key to producing a successful project.

Team Objective

The objective is to design and build a vehicle that meets the rules and regulations of the 2017

Baja SAE competition. Team Xtreme will represent the University of Houston and participate in

the competition that will take place in Pittsburg, Kansas on May 25-28, 2017.

Deliverables

Register for the 2017 Baja competition in Pittsburg, Kansas by the November 14, 2016

deadline

Have a Baja vehicle that is mechanically complete with a functioning suspension assembled

by December 2016

Manufacture carbon fiber uprights for the suspension

Achieve a vehicle weight under 400 lbs.

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Pass the Baja SAE inspection for the competition

Achieve a top speed of 30 mph on a flat surface

Design a vehicle that can achieve a flat jump of 7 ft.

Implement instrumentation that is capable of data acquisition

The deliverables were approved by Dr. Raresh Pascali and are intended to be met by May 2017.

One important note is that in order to meet the second deliverable and have a vehicle that is

mechanically complete with a functioning suspension assembled by December 2016, Team

Xtreme will be using some of the components that were designed and fabricated by the Baja

Brigade senior design team.

History

The first Baja SAE Competition was held in 1976 at the University of South Carolina in Jackson,

SC. Ten teams registered for this event with ninety students participating. The competition was

eventually divided into 3 regions: East, Midwest, and West. In 1978, the first Midwest and West

regions competition was held in Milwaukee, WI, Arizona state university, and Phoenix, AZ

respectively. The number of teams that participated continued to grow every year after the first

event. By 2016, 100 teams registered with more than 1000 students participating in all three

regions. Over the years, the Baja SAE Competition has spread to other countries outside of

North America. Brazil’s first Baja SAE event was held in 1995 with 10 registered teams and 90

participating students. Korea’s first event was hosted by Yeungnam University in 1996 with 10

teams and 280 students. South Africa’s first event also started in 1996, hosted by the University

of Pretoria with 4 teams and 12 students.

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Event Categories

The dynamic event and static event are the two main categories in the Baja SAE competition.

The dynamic and static events are divided into separate sections. Some of the dynamic

subcategories vary from event to event based upon the place the competition is held. These

events with sub categories and possible points for each event are listed in Table 1.1 and Table

1.2 below:

Dynamic Event

Acceleration: Tests the vehicle’s ability to pick up speed quickly from a starting point.

Each vehicle may take two attempts in this event and they are tested on a flat surface for

100 ft. or 150 ft. The following equation is used to calculate the acceleration score:

where:

tshortest = fastest time by any vehicle

tyours = time for the vehicle to be scored

longest = the lesser of: a) slowest time by any vehicle; b) 1.5tshortest

Land maneuverability: Vehicle should be able to go on bumps, sand, rocks, logs etc.

Hill climb/Rock climb: Vehicle should reach the destination point without stopping.

Traction event: Tests the vehicle’s ability to climb an incline surface or pull an object on

a flat surface

Table 1.1

Table 1.2

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Endurance: Ability to operate continuously in any weather conditions for a total of 4

hours.

Static Event

Design event: The objective of the design event is to evaluate the engineering effort put

into the design of the team’s vehicle. The vehicle’s design is expected to be safe and

ergonomic. This event is judged based on design specifications, analysis, testing

development, manufacturability and also serviceability. System integration is taken into

consideration. Design reports should contain a brief description of the team’s vehicle,

design objectives, concept details, and details of key design structures. Design and

specification reports need to be submitted on or before the due date listed in Baja SAE

website (www.bajasae.net) prior to the competition. Late submissions are accepted with

a 10-point penalty per day up to 5 days. After 5 days the team’s registration will be

cancelled.

Cost event: Teams must provide supporting documents to verify the cost calculations for

the proposed model and the actual cost of the particular prototype model. Cost reports

must be submitted including copies of price tags, receipts, invoices, catalog pages, online

prices for every item that costs more than $30.

Sales presentation: The objective of the presentation is to convince a hypothetical

company to purchase the team’s Baja SAE vehicle design and put it into production to

manufacture 4000 vehicles per year. One or more members can present the sales

presentation and it is limited to 10 minutes. Five minutes max for the presentation, and 5

minutes for questions and answers. Teams may get bonus points for this event if the

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team’s scores are tied. Judges for this event may include a combination of corporate

executives who may have experience in marketing, production and finance as well as

engineering.

Previous Winners

2016 2015 2014

University Univ. of Michigan Cornell University Cornell University

Team Michigan Baja Racing Big Red Racing Big Red Racing

Dynamic 696.40/700 683.35/700 672.87/700

Static 311.03/300 293.70/300 257.16/300

Overall score 1007.43/1000 977.05/1000 930.03/1000

Winning strategy

Improvement: Most of the top ten teams are using the same vehicles for many

competitions. These teams are making continuous improvements on the vehicle from the

previous competition. They are focusing on the events that they scored low points in the

previous competition.

https://www.facebook.com/CornellBajaRacing/photos

Table 1.3

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Funding: Many of the top 10 teams received a majority of the funds from their respective

university.

Vehicle Weight: Winning teams achieved a vehicle weight of less than 400 lbs. Some of

the top ten teams used ultra-high molecular weight polyethylene materials for the body,

light weight hammock materials for the seats, and light weight composite materials for

the floor. By using these materials, they were able to keep their vehicle weight under

400lbs.

Achieving maximum points in static event: They also used some electronic devices such

as LCD monitors, driver communication system, and speed sensors. Using these devises

effectively they were able to scored bonus points in the static events.

Major Design Components

The major components of the Baja SAE vehicle are the chassis, suspension, engine,

transmission, brakes, and steering. Each component was researched individually to calculate

costs, availability and standards used throughout other vehicles participating in the Baja SAE

competition.

Chassis

The chassis is a series of tubes connected together to form a coherent structure. The chassis

provides a rigid connection between the rear and front suspension and creates and overall

structural support for other necessary systems of the vehicle. The design of the chassis is

important to support the other components in their respective positions. It also serves as the base

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of the entire vehicle. It is extremely important because it provides the necessary protection for

the driver if the vehicle is to receive a substantial amount off impact due to a crash or roll over.

There are also certain restrictions that the Baja SAE

competition regulates such as the dimensions of the

overall frame. The maximum length allowed is 108

inches while the maximum width allowed is 64 inches.

The dimensions are shown in Figure 1.1 to the left. The Baja SAE rules also state that the vehicle

must at least be able to fit a driver that is 75 inches tall and weighs 250 pounds.

There are two standard design structures that could potentially be used in the Baja SAE which

are the spaceframe design and a combination of a monocoque and spaceframe design. The design

of an entirely monocoque chassis would not be a design that is permitted to enter the competition

due to the rule that restricts the use of steel for all of the required frame members. The only

design that would be allowed would be a hybrid version of the spaceframe design in combination

with a monocoque design that would have the body panels double as stress members. Although a

hybrid version of that design would be innovative and advantageous, the spaceframe design is

widely used for the vehicles that participate in the Baja SAE competition because of the ease of

fabrication of the structure and the ability to easily make modifications if needed.

In order to meet the deliverable of having a complete rolling chassis by the end of December

2016, under the approval of the instructor, the frame that was designed and fabricated by the

Baja Brigade senior design team will be completed by Team Xtreme. The team will complete the

welding on the frame and build on the design that was originally considered by the Baja Brigade

team. The team will reconsider the material and design in the second semester and make

modifications if necessary, in order to meet the weight requirement listed in the deliverables. The

Figure 1.1

Figure 1.1

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frame is built with AISI 1018 steel. The frame was only tack welded by the previous team. Team

Xtreme completed the welding on all member of the frame using an arc welding machine with

E6013 welding electrodes. The welds were grinded down to achieve a good finish and the frame

was sanded down to remove the rust and prepared to apply a coat of primer paint and then the

finish color.

Some of the possible materials that the team researched if the frame was to be re-designed or

modified are listed below in Table 1.1. The materials will be looked at more in depth during the

second semester to finalize the decision on whether any modifications are needed to fit the frame

or whether a different material will be used on a new frame design.

Suspension

One of the major challenges of building an SAE vehicle for the competition is to design and

fabricate a suspension that is capable of handling the different terrains that will be present during

the competition. When designing the suspension of any vehicle there are three major angles to

consider that will affect the handling, steering and stability. The camber is the angle of the wheel

relative to the road. In the figure below the angle of the wheel is taken by looking at the car from

the front view (Figure 2.1). Caster is the angular displacement of the steering axis from the

vertical axis of the wheel (Figure 2.2). The toe angle is the symmetric angle that a wheel makes

with the longitudinal axis of the vehicle (Figure 2.3).

Table 1.4

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Although there are different types of suspension linkages that could be designed and used

for a Baja vehicle, the most common suspension linkage used for the front suspension is a

double wishbone also known as double A-arm. The double wishbone suspension consists

of two A-arms, of either equal length, known as equal length A-arm setup or different

lengths, one shorter than the other, known as unequal A-arm setup as shown in the

figures below:

Figure 2.1 Figure 2.2

Figure 2.3

Figure 2.4 Figure 2.5

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In a double wishbone suspension each arm has three pivot points which connect the

suspension to the frame and the steering. One point is connected to the steering knuckle

and the other two points are connected to the frame.

Another common suspension design used for the Baja vehicle that is typically used for

the rear suspension is a trailing arm suspension. The main factors that are considered for

the rear suspension is weight, cost and functionality. The concept of the trailing arm

suspension is simple and its main characteristic is that it connects the frame to the

knuckle with a single arm.

A multilink suspension is another type of suspension linkage that can be used but it’s

more complex than a double wishbone suspension or a trailing arm suspension. It has

better functionality as the suspension is made of two or more links that change the shape

of the arm as the wheel is turned instead of using two solid upper and lower A-arms. The

figure below shows the concept of a multilink suspension linkage:

Figure 2.6

Figure 2.7

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Engine

Every vehicle participating in the 2017 Baja SAE competition is required to use the Briggs and

Stratton Model 19 engine during the event (Model# 19L232-0054-G1). Any modifications to the

engine are strictly prohibited and will result in disqualification of the team. The Model 19 is a 10

HP, four cycle, air cooled engine that is donated by the Briggs and Stratton Corporation to all

participants that register for the competition. The teams are in charge of paying the $250 fee for

shipping and handling of the required engine.

Drivetrain

The drivetrain is a very crucial component of the vehicle. It is the component that delivers the

power from the engine to the wheels. One major factor to consider is that every team in the

competition will be using the same engine without any modifications, so in order to achieve

more efficiency in the power that is delivered to the wheels; the team must closely look at the

design of the drivetrain. Another aspect that is important to the team is meeting the deliverable

which states that the Baja vehicle will be able to achieve a top speed of at least 30 mph on a flat

surface. In order to successfully design a vehicle that not only meets that deliverable but can also

deliver enough power to handle the rough terrains of the competition certain design constraints

must be considered such as the engine limitations that have been specified. The need for a

lightweight and compact transmission that is susceptible to the space allotted in the frame and

that has the ability to adjust from high to low gears depending on the terrain encountered during

the competition. The two possible options for the drivetrain that the team is currently considering

are either a manual transmission or an automatic transmission and the advantages and

disadvantages that each one has.

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Automatic transmissions such as a Continuously Variable Transmission (CVT) are the

most commonly used in the vehicles that participate in the competition. CVT’s are very

effective in the competition due to their ability to automatically adjust to the traction

requirements. A CVT has a greater shifting range than manual transmissions and it is best

suited for acceleration. The challenge with CVT transmissions is that tuning is a very

crucial aspect and in order to tune it expertise and knowledge are required.

In manual transmissions, torque and speed are restricted on gear shifting but they are less

complex than CVT’s and tend to be less costly as well. Manual transmissions also require

less maintenance and give the driver more control on the performance of the vehicle.

Another benefit is that manual transmissions tend to also weigh less than their

counterpart automatic transmissions.

Steering Design

The steering connects to the vehicle’s suspension and allows the driver to gain control of the

vehicle maneuver and guide it through the desired course. The steering system essentially

connects the front wheels, to the steering wheel that is located in front of the driver via the

steering column. Factors such as the turn radius and steering stability are affected depending on

the design of the steering system therefore it is essential that it is design effectively.

The rack and pinion design is the most common design used for steering in the Baja SAE

vehicles. The design is simple and consists of the steering wheel, attached to the steering

column, the rack and pinion, tie rod and kingpin. The figures below show the setup of the

rack and pinion.

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The advantage of the rack and pinion system is that it has relatively fewer parts than other

steering systems therefore it is lighter and easier to repair. Having fewer components also

allows for more responsive turning and control over the vehicle. One disadvantage is that

the system transfers more vibrations to the driver and although it provides great handling

on smooth terrain, it needs a greater force to turn the wheels on uneven or rough terrain

which causes the system to wear out faster.

Recirculating-ball steering is another type of steering design which the steering column

turns a large screw which meshes with a nut by recirculating balls. The nut moves a

sector of a gear causing it to rotate about its axis as the screw is turned. The pitman arm

which is connected to the steering linkage is moved by the arm that is attached to the axis

sector. Figure 5.3 below shows the recirculating-ball steering design.

One advantage of this design is the ability to have more or less steering travel than a rack

and pinion system and it is also less expensive. One drawback is that is less efficient than

Figure 5.1

Figure 5.3

Figure 5.2

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a rack and pinion system and it has so many components that it makes it heavier. Due to

friction it is more prone to wear.

Project Management

In order for Team Xtreme to successfully complete the project on time and meet the other

proposed deadlines and goals certain constraints were laid out as the foundation of the project.

The scope, time and budget are the primary constraints of the project. In the initiation process, all

through the planning, execution, and closing of the project, the potential risks were identified, the

work break down structure was created and the timeline was generated to increase productivity

and to allow the team to successfully manage the project from start to finish.

Budget

The highest costs for the entire project includes the

suspension, registration fees and the travel expenses for

the 2017 Baja SAE competition in Kansas. The mitigation

for those high costs include the use of available donated

parts for the suspension, make fundraising a weekly focus

throughout the semester to raise enough funds for the

registration fees and use a members’ vehicle and borrow a

trailer to reduce the cost of travel and also check routinely

for deals on lodging.

Table 1.5

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Timeline

Listed in the Appendix (Figure A1) at the end of the report is the timeline for the entire project

which is designed to help the team stay on track. One of the keys to having a successful project

build is time management coupled with strong team work. The timeline has been developed to

keep everyone on track and aware of our current position as well as how much work still needs

to be done. So far we have left the research of the major components open considering we will

tackle most of those tasks in the second semester. Currently we are on the design phase 1 section

of the timeline. In addition to designing the suspension we have also started finishing fabrication

on the existing frame.

Work Breakdown Structure (WBS)

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Risk Matrix

Risk:

1) Funding

2) Manufacturing with composite materials

3) Fabrication

4) Time management

5) Meeting SAE requirements

Mitigations:

Continue talking to potential sponsors and use donated parts

Recruit industry help

Recruit experienced welder

Hold weekly meetings and track time sheets

Consult with previous teams and review rulebook

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References

"BAJA Automotive Enthusiasts." Baja Tutor Knowledge Base for BAJA Automotive Enthusiasts.

Web. 15 Oct. 2016. <http://bajatutor.org/>.

"Baja SAE Kansas." - Baja SAE. Web. 1 Sept. 2016. <http://students.sae.org/cds/bajasae/east/>.

CADmantra Technologies Follow. "Chassis Design for Baja Sae." Chassis Design for Baja SAE.

26 Sept. 2015. Web. 26 Sept. 2016. <http://www.slideshare.net/bholapatel/chassis-

design-for-baja-sae>.

"Intrax Racing." Intrax Racing. Web. 20 Oct. 2016. <http://en.intraxracing.nl/techniek/camber,-

caster,-toe-intoe-out/>.

Isaac-Lowry, By Jacob. "Suspension Design: Types of Suspensions - Automotive Articles .com

Magazine." Suspension Design: Types of Suspensions - Automotive Articles .com

Magazine. Web. 6 Sept. 2016.

<http://www.automotivearticles.com/Suspension_Design_Types_of_Suspensions.shtml>.

Michael, John. "The Advantages of Rack & Pinion Steering." EHow. Demand Media. Web. 01

Nov. 2016. <http://www.ehow.com/list_6102863_advantages-rack-pinion-

steering.html>.

"Rack and Pinion Steering System | Advantages | Application." Mechanical Engineering World.

Web. 1 Nov. 2016. <http://www.mechengg.net/2015/03/rack-and-pinion-steering-

system.html>.

"Recirculating Ball." Wikipedia. Wikimedia Foundation. Web. 07 Nov. 2016.

<https://en.wikipedia.org/wiki/Recirculating_ball>.

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"SAE Baja Car." MiniBuggyNet The Ultimate OffRoad Buggy Community RSS. Web. 20 Oct.

2016. <http://www.minibuggy.net/forum/show-off-your-toys-here/6776-sae-baja-car-

7.html>.

Singh, Avinash. Off-Road Suspension Design. 2016. Amazon Inc.

"Trailing Arm or Semi Trailing Arm." Official Baja SAE Forums. Web. 22 Sept. 2016.

<http://forums.bajasae.net/forum/trailing-arm-or-semi-trailing-arm_topic1834.html>.

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APPENDIX

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Figure A1 - Timeline

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Figure A2 – Gantt Chart

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Sponsorship Brochure