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Solar Opposers Moon Buggy 2

Solar Opposers Moon Buggy 2 Presenters: Donna Durkee Jeremy Apt Charlie Tullis Craig Scholes Piyush Goyal Ryan Carr Final Presentation Advisory Committee April 27, 2007 Table of Contents Budget Schedule Design Considerations Design Changes PSU Hub Manufacturing Stress Test

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Solar Opposers Moon Buggy 2

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  1. Solar OpposersMoon Buggy 2 Presenters: Donna Durkee Jeremy Apt Charlie Tullis Craig Scholes Piyush Goyal Ryan Carr Final Presentation Advisory Committee April 27, 2007

  2. Table of Contents • Budget • Schedule • Design Considerations • Design Changes • PSU Hub • Manufacturing • Stress Test • Testing • Performance • The Race

  3. Budget Craig

  4. Schedule Craig

  5. Schedule (cont) Craig

  6. Design Considerations • Projected drivers weight: 350lbs • Target vehicle weight: 100lbs • 3 gears • Max top speed: 30mph • F.S. • 2 on Frame and seats • 4 on suspension and hubs Donna & Ryan

  7. Design Considerations • Targeted turning radius: 10ft • Steering • Turning radius • We are shooting for approximately 10ft • Bent tie rods - • Solution • Moved bell crank forward • Longer bell crank arms Ryan & Donna

  8. Design-Changes • Seats-Mesh bucket • Shortened Frame • Plastic Fenders • Chains gears • 35 roller chain • 1:1 Gear Ratio • 3 speed Shimano internal gear shifter • Minor Changes to frame Donna

  9. Design-Criteria • Shortened Frame • Turning radius 10ft or less • Total length 7 ft 3 in • Plastic Fenders • 17.83 mph • Ending weight 195 lbs • 4x4x4 box • Steering • 2 useable gears Donna

  10. PSU Hub Design • Envelope • Design Conditions • Forces • Materials • Casting • Casting Failure Donna

  11. Envelope • Hub is attached to control arms at 3 point • Top-1 point, Bottom- 2 points • Control arms are 0.75 inch square tubing Donna

  12. 3D View of Envelope Donna

  13. Top View of Envelope Donna

  14. Front View of Envelope Donna

  15. Right View of Envelope Donna

  16. Design conditions • Weight= 1.0 lbs per hub • Drawing measurements in inches • Final Design • Weight = ¾ lb Donna

  17. Forces • Forces • 200 pound upward force (positive z direction), on wheel from weight, • Wheel center is 2 inches from edge of the hub • 50 pound in the negative y direction for impact • Safety factor of 4 Donna

  18. Hub Material • Al 356 T6 Aluminum Cast Alloy • Pour Temperature 1485°F • Titanium Boron Grain Refined • T6 Heat Treatment • 8 hr at 915°F • Instant Quench • 4 hr at 310°F Charlie

  19. Hub Material Al 256 T6 Aluminum Cast Alloy

  20. Casting • Green Sand Mold • Sodium Silicate bonded sand for core • Flask size: 20” x 14” x 4/8 • Follow board to establish parting line • Provided by Jeremy and Red Ball Pattern Shop • 3” diameter x 4” ￪ riser in gating • Draft angle Charlie

  21. Casting Failure • Impact Load • No defect in casting or metallurgy • Repair • 100% penetration Tig welded fracture • Reinforcing web added • Al 6061 T6 forged alloy • ¼” Plate • Cost of repair • $210 Charlie

  22. Manufacturing • Kept Original Plan • Frame • Cut parts • Fit and weld parts • Steering • Drive train & chains • Hubs • Shocks & tires • Minor Changes to Plan • The steering moved below the drive train and hubs Donna

  23. Manufacturing • Complications & Changes during Manufacturing • The chains • 45 roller to 35 roller • Hime Joints • For travel Issues • Angles • Seat supports • Compound miter • Drive shaft • 3/8” out of square • Steering Handle • Pinned for 4x4x4 criteria Donna

  24. Manufacturing • Processes used • Mill • Angles on tubing • Lathe • Turn down drive shaft • Machine hub • Water Jet • Shock mounts • Differential Mounts • Seat base • Hem Saw • Frame Tubing Donna

  25. Manufacturing Donna

  26. Manufacturing Donna

  27. Manufacturing Donna

  28. Stress Test • A force of 6000lb was applied at a 10 degree angle • Which broken into components is a 5900lb force directed along the frame (-y) direction • a force of 1000lb in the (+z) up direction • The 6000lb force was if it hit a curb at an angle with one of the front tire absorbing the force and deforming ¾” in the x direction Craig

  29. Stress Test • There was considerable deformation but no high stress areas (red) appearing • Which to us implies that it would not break • There may have been an error in the constraint rotation • We figured it would have shown more rotation Craig

  30. Stress Test Craig

  31. Stress Test • A force of 300lb was placed on each peddle • This may have been high because we took the highest amount leg pressed by the drivers • This is with both legs and not just one • The peddles were fixed and only allowed to rotate about the x axis Craig

  32. Stress Test Craig

  33. Test Plans • STRUCTURAL TESTS Collision, Vibration, Sound Test. Crack Testing. • PERFORMANCE TESTS Functioning of Brakes, Suspension, Turning Radius Test. Piyush

  34. Structural Tests • COLLISION TEST Crashed the buggy into a metal hopper with a speed of 5 miles per hour. RESULTS A bent front left tire. We had to replace the tire with a new one. Piyush

  35. Structural Tests • VIBRATION AND SOUND TEST This test wasperformed during the test drive of the buggy. RESULTS We found out that some of the nuts and bolts were not tightened. And we also had to adjust the tension on the chains that connects the internal hubs to the drive shaft. Piyush

  36. Structural Tests • CRACK TESTING We planned on doing crack testing on the rear hubs using the Ultra Sonic Tester. RESULTS Due to lack of time we were not able to do the tests. Piyush

  37. Performance Tests • We had a test track which helped us determine some of the problems that we faced on the day of final race. • We had a brake test on the buggy and found out that the stoppage time at a speed of 10 miles per hour was 2 feet. • During the test drive, the buggy fell off the mogul which resulted in breakage of the rear right hub and a crack on the left hub. • We repaired the hubs and also built replacement hubs out of steel just in case the hubs failed again. Piyush

  38. Performance • Steering Issues • Drive Hub Issues • Suspension • Seats Jeremy

  39. Pros: Simple to make Sturdy design Cons: Slowed Assembly time due to pin Multiple re-designs 4x4x4 Steering Issues Jeremy

  40. Drive Hub Issues • Reused part • Slight alignment problem with chains • Slack in the internal gears • Which caused some slippage during the race. Jeremy

  41. Shocks and Seats • Good design on the shock mounts • Good positioning of shock mounts allowed for better performance • If softer never would have gotten airborne over obstacle 3, and no bottoming out over obstacles • Seats • Most expensive part on buggy • Comfortable and soundly designed Jeremy

  42. The Race Jeremy

  43. Penalties • Off course - • due to the steering being loose • Lower gear - • Easier to remove one’s buggy from obstacles Jeremy

  44. On-Board Electronics • Digital Camera • On board view of the race from the front of the buggy. • Speedometer • Recorded actual race data • Top speeds thru out the course Jeremy

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