BAJA SAE 2010 Conceptual Design Review Statement of

BAJA SAE 2010 Conceptual Design Review

Statement of Work �Baja SAE is an international collegiate design competition sponsored by the Society of Automotive Engineers. The program simulates real-world engineering design projects and the related challenges with the goal of developing and building a small off-road vehicle. Teams from around the world compete in static and dynamic events to have their design accepted for manufacture by a fictitious firm.

Team Responsibilities � Sam Moran – Chief Executive Officer; Frame Designer; Welder/Grinder � Michael Guilfoy – Steering Engineer; Chief Financial Officer; Welder/Machinist � Sam Weitkemper – Drivetrain Engineer; Executive Secretary � Ben Mc. Nealy – Braking Engineer; Analyst; Director of Internet Services � Matt Wantland – Analyst; Materials Acquisition Specialist; Fabricator � Dan Pickering – Suspension Engineer; Chief Mechanic � Ahmed Al-Gattan – Chief Safety Officer

Customers � SAE Competition Fictitious Firm � Safe vehicle � Maneuverability, Traction, Suspension, Acceleration � Design/Manufacturability � Cost � Sponsors � Competitive vehicle � Promotion � Faculty Advisors � Competition success � Educational experience

Benchmarking �Vehicle Engineering Specifications � Front Track Width � Rear Track Width � Wheelbase � Weight � Suspension � Drivetrain �Data from 2009 Baja SAE Alabama competition

Benchmarking Number of Teams Using a Specific Wheelbase 8 7 2010 TU car Number of Teams 6 5 4 2009 TU car 3 2 1 0 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 Wheelbase (in. )

Benchmarking Number of Teams Using a Specific Front Track Width 16 14 Number of Teams 12 10 8 6 2010 TU car 4 2009 TU car 2 0 48 49 50 51 52 53 54 55 56 57 58 59 Front Track Width (in. ) 60 61 62 63 64 65

Benchmarking Number of Teams Using a Specific Rear Track Width 16 14 Number of Teams 12 2010 TU car 10 8 6 2009 TU car 4 2 0 49 50 51 52 53 54 55 56 57 58 Rear Track Width (in. ) 59 60 61 62 63 64

Benchmarking � Analysis of top 11 overall performing cars from 2009 Baja SAE Alabama competition Specification Value Wheelbase (in. ) 62. 2 Front Track Width (in. ) 57. 6 Rear Track Width (in. ) 54. 9 Weight (lbs. ) 396. 3

Frame Concept 1 – The Nose Box � Advantages: � simple � few packaging constraints � Disadvantages: � inefficient use of space

Frame Concept 2 – Integrated Cockpit � Advantages: � more legroom � efficient use of space � light � Disadvantages: � Complicated design

Frame Concept 3 – “The Cage” � Advantages: � simple design � requires the least amount of planning � allows for last-stage drivetrain changes � Disadvantages: � heavy � difficult drivetrain maintenance

Frame Concept 4 – Double Loop � Advantages: � lightweight � efficient � easy drivetrain maintenance � Disadvantages: � difficult to design � not conducive to double a -arm suspension � stuck with drivetrain choices

Frame Concept & Design � Front � Length designed for the reach of the team’s smallest driver � Clearance designed for the 95 th percentile male � Integrated cockpit design � Rear � Double loop design inspired by Queen’s University � Frame members do not interfere with removal of drivetrain components � Weight: 73 lbs � Length: 80. 5” � Width: 31. 0” � Height: 52. 9”

Final Frame Design

Frame Material �Given in 1018 PCS � 2 different specifications Strength/Stiffness � Critical Components – Roll Cage � Non-Critical Components – frontal/side impact

Sizing Calculations Roll Cage Requirements mm Inches 1018 Steel Outer Diameter 25 0. 984 Density (g/c 3) 7. 87 Wall Thickness 3 0. 1181 E-Modulus (Gpa) 205 Sultimate (Mpa) 440 Syield (Mpa) 365 I (mm 4) 12777. 64 c (mm) 12. 5 Bending Strength Bending Stiffness M = Syield*I/c Stiffness = E*I Min---> Max Moment (N-m) 373. 11 Min---> Max Moment (lb-ft) 274. 96 Min---> 2619. 42 Stiffness (N-m 2)

Tubing Possibilities Tubing Size (in) Minimum 0. 75 X. 080 1. 00 X 0. 095 1. 25 X 0. 095 1. 28 X 0. 071 1. 00 X 0. 060 �Hi Source X Tenaris Quik. Service Yield (Mpa) Strength (N-m) Stiffness (N-m 2) Weight (lbs/ft) X 375 2620 X 480 225 817 0. 57 620 627 2385 0. 91 550 903 4937 1. 17 365 462. 1 4218. 7 0. 91 365 235 1676 0. 6 Performance – Expensive/Light �Economical – Cheap/Heavy �Compromise – In between

Frame Specifications Lengths of Different Tubing Large Req. Tubing (ft) 25 Small Req. Tubing (ft) 68 Non Required (ft) Option 1 - Economical 2 - Hi-Performance 3 - Compromise 0 Cost $0. 00 $650. 00* $40. 00 Final Tubing Sizes Lrg OD (in) 1. 28 Lrg t (in) 0. 071 Sm OD (in) 1 Sm t (in) 0. 06 *http: //www. airpartsinc. com/products/4130 -steel-tubing. htm Frame Wt. (lbs) 92 44. 2 63. 8

Drivetrain Benchmarking Team Oregon State South Florida Sherbrooke Cornell Maryland SUNY Buffalo Rochester Tech SUNY Stony Brook Transmission CVT w/ transaxle 6 -speed gearbox CVT w/ chain drive Differential driver-lockable open solid rear axle limited slip CVT not specified CVT w/ transaxle auto-locking not specified auto-locking CVT w/ transaxle limited slip

Drivetrain Concept #1 �CVT with chain drive �Pros: lightweight, simple, cheap �Cons: no reverse gear, requires tensioning system

Drivetrain Concept #2 �Motorcycle gearbox with chain drive �Pros: easy to find, includes reverse gear �Cons: more difficult for the driver

Drivetrain Concept Chosen �CVTech CVT with Dana H-12 transaxle �Pros: Simple, proven reliability, F/N/R, autolocking differential �Cons: Heavy

Drivetrain Layout

2010 Axle Design

Drivetrain Specifications Max Ratio Min Ratio Top Speed Max Gradient Max Engine Power Max Engine Torque Idle Max RPM Weight Tire Diameter 39. 75 (35. 60) 5. 70 (6. 98) 34 mph (35 mph) 52 % (70%) 9. 1 HP 13. 8 ft-lbs 1750 3800 120 lbs 22”

Front Suspension � Double A-arm configuration � The front suspension system for a majority of the cars at last year’s competition � Benefits � The length and orientation of the arms can be designed for the vehicle’s application. � Computers can be used to design the suspension geometry

Front Suspension � The vehicle was designed around the suspension mounting points � To prevent conflicts between the suspension and other vehicle components � Mechanism synthesis was performed in Solid. Works with the help of Dr. Daily

Front Suspension � Mounting points � Geometric constraint analysis was performed to determine the suspension mounting points for a given tie rod length and designed for no bump steer � Constraints: 5 degrees of camber and 10 inches of vertical travel for a 52 inch front track width � Top arm length: 16. 375” � Bottom arm length: 16. 50”

Front Suspension � Roll center � The front roll center was determined using Solid. Works � For the desired mounting points, the roll center was found to be about 3. 05 inches above the ground

Rear Suspension � Solid Rear Axle/ Swing Arm � Top finishers such as Queen’s University and Michigan University used a swing arm with a solid rear axle. � Double �A A-arm majority of the cars at last year’s Mini Baja used a double wishbone configuration. � More appropriate for cars without a solid rear axle � Simple � After discussing options with the team, a double wishbone configuration was chosen

Rear Suspension � Mounting points � Geometric constraint analysis was again performed to determine the suspension mounting points � Constraints: no camber change and 8 inches of vertical travel for a 50 inch rear track width � Top arm length: 16. 50” � Bottom arm length: 16. 50”

Rear Suspension � Roll center � The rear roll center was determined using Solid. Works given parallel equal length arms � For the desired mounting points, the roll center was found to be at the ground

Shocks and Springs � The shock mounting points were set by the frame design and restrained by the control arm movement. � The ideal shock travel for the given wheel travel was determined from mechanism synthesis.

Steering Concepts � Power Steering � Additional � Requires components power � Complicated integration inside steering box � Four-Wheel Steering � Challenging � Untested integration in competition conditions

Steering Concepts � Rack and Pinion Steering � Simplified system � Light � Ease of integration with suspension � Used by nearly every Baja SAE team

Ackerman Geometry 51” 62. 5”

Modeling Steering Angles 27. 73° Outside Wheel Lock Position 45. 49° Inside Wheel Lock Position

Turning Radius Results Turning Radius Composition 12 Turning Radius (ft) 10 8 6 4 2 0 Track Width Wheelbase Track Width (in) 52. 00 Wheelbase (in) 60. 00 Steering Angle (deg) 36. 61 Turning Radius (ft) 10. 55

Steering Specifications � Chosen � 14 Concept: Rack and Pinion inch length; 4. 5 inches of travel � 1. 5 turns lock-to-lock � Turning radius of approximately 10. 5 feet � Ackerman Geometry � Tie Rod Connection � Rack mounting to minimize lateral loads � Rack mounting considered in frame design � Front Suspension design clearance issues addressed

Braking Concepts � Rules require two independent hydraulic systems � Disc brakes � Light � Compact � Used � Drum by nearly all Baja teams brakes � Heavy � Bulky

Braking Concepts � Single cylinder, dammed reservoir � Pros: simple, packaging flexibility � Cons: longer than dual cylinders � Dual cylinders, overhead mount � Pros: shortest overall length � Cons: aesthetics � Dual cylinders, floor mount � Pros: elegant packaging � Cons: longer, may conflict with steering components

Braking Concepts � Rigid lines � Pros: Rigid, look good � Cons: Difficult to install � Braided � Pros: flex lines Flexible, easier to install � Cons: Heavier

Braking Concept Selected � Polaris discs and calipers � Dual US Brake master cylinders � Wilwood reverse mount pedal � Braided steel flex line

Safety �Braking � Two independent hydraulic braking systems � Capable of locking the wheels � No plastic brake lines �Drivetrain � CVT cover – made of polymer � Gas catch – made of polymer �Kill Switches � Two kill switches required � One in cockpit, one in rear

Safety �Frame pads � The minimum required thickness is ½”. � The cost is $17. 95 per 3 feet. � Need 6 feet. �Safety � Motor helmet cross style, Snell M 2005 specification

Safety �Fire extinguisher � Two 5 B-C extinguishers. � One must be mounted next to the driver and the other in the pit area. � Head restraint

Goals and Deadlines � January 25 – complete design � stress analysis � CAD models � February 28 – drivable vehicle � rolls under its own power � basic safety gear � March 28 – competition-ready vehicle � meets all rules � fully functional, painted, polished, done. � April 8 -11 – 2010 Baja SAE Carolina competition

Schedule

Budget Retail Cost Customer Cost Vehicle System Costs Frame Tubing - Purchased System Total Transaxle Engine CVT Rear Drive Axles Miscellaneous System Total Suspension Shocks A-Arms Wheel Uprights System Total $ 750. 00 $ 350. 00 $ 1, 100. 00 $ 1, 320. 00 $ 450. 00 $ 130. 00 $ 1, 000. 00 $ 885. 00 $ 3, 785. 00 $ 1, 160. 00 $ 250. 00 $ 768. 29 $ 2, 178. 29 $ - $ 100. 00 $ - $ 450. 00 $ 130. 00 $ 1, 000. 00 Travel to South Carolina Hotel $ 1, 000. 00 Transportation and More $ 1, 000. 00 $ 2, 000. 00 $ 1, 000. 00 $ 3, 000. 00 $ 2, 000. 00 $ 800. 00 $ 300. 00 $ 100. 00 $ 250. 00 $ 400. 00 $ 300. 00 $ 100. 00 $ 250. 00 $ 1, 450. 00 $ 1, 050. 00 TOTAL Entry Fee TOTAL COMPETITION EXPENSES Driving/Safety Gear $ 680. 00 $ 2, 260. 00 Team Uniforms Office Supplies $ 1, 160. 00 $ 250. 00 $ 374. 00 $ 1, 784. 00 Rack and Pinion Accessories System Total Braking Tires and Maintenance $ 98. 00 $ 247. 00 $ 345. 00 $ 1, 124. 09 $ 396. 00 $ $ - Team Operation Expenses Fabrication Tools TOTAL OPERATION EXPENSES Team Labor Expenses Total Engineering Steering Customer Cost Competition Expenses Tubing - Donated Drivetrain Retail Cost $ 98. 00 $ 247. 00 $ 345. 00 TOTAL LABOR EXPENSES $ 433. 00 $ 160. 00 Total Anticipated Costs Total Fabrication Total Testing Retail Cost $ $ 97, 500. 00 $ $ 43, 350. 00 $ $ 10, 500. 00 $ $ Customer 151, 350. 00 $ 165, 228. 38 $ - Cost 8, 632. 00 -

Budget Retail Cost Competition Expenses Customer Cost $ 3, 000. 00 $ 2, 000. 00 Frame $ 1, 100. 00 $ 100. 00 Drivetrain $ 3, 785. 00 $ 2, 260. 00 Suspension $ 2, 178. 29 $ 1, 784. 00 Steering $ 345. 00 Braking $ 1, 124. 09 $ 433. 00 Tires and Maintenance $ 396. 00 $ 160. 00 Miscellaneous $ 500. 00 $ 9, 428. 38 $ 5, 582. 00 Team Operation Expenses $ 1, 450. 00 $ 1, 050. 00 Team Labor Expenses $ 151, 350. 00 $ - Total Anticipated Costs $ 165, 228. 38 Vehicle System Costs TOTAL VEHICLE EXPENSES $ 8, 632. 00

Budget Hourly Rate Extended Cost Item Description Engineering Design & Analysis $75. 00 $0. 00 1300 $97, 500. 00 $0. 00 Fabrication Machining Time $50. 00 $0. 00 30 $1, 500. 00 $0. 00 Welding Fixtures $45. 00 $0. 00 12 $540. 00 $0. 00 Tube Bending $45. 00 $0. 00 6 $270. 00 $0. 00 Welding $45. 00 $0. 00 72 $3, 240. 00 $0. 00 Assembly $45. 00 $0. 00 840 $37, 800. 00 $0. 00 Testing & Analysis $75. 00 $0. 00 140 $10, 500. 00 $0. 00 2400 $151, 350. 00 $0. 00 Testing Total Labor Costs Retail Rate Customer Rate Quantity Retail Cost Customer Cost