1. L UNAR W HEEL MAE 435 Spring 2014 Seth Hughes Robert York James Taylor Alicia Najor Shannon Green Trucmy Nguyen David Palmer

2. Gantt Chart

3. Major Concerns ●Lunar conditions ○Extreme temperatures ○Radiation ○Solar wind ○Large jagged rocks that create point loads ●Regolith ○The moon’s dust (regolith) is electrostatically charged and very abrasive ○Clogs wheel components ●Traction ○Slippage across an incline ○Slippage traveling up an incline

4. Introduction ●Improvements upon last year’s wheel ○Replace welds with aerospace adhesives ○Handle point loads better ○Improve traction

5. Methods: Design ●Lack of exact vehicle constraints ○Main focus of design concept is based on the lunar environment constraints ●Regolith and various sizes of meteor fragments ○Large fragments cause extreme point loads ■Outer surface of the wheel needs to be flexible and durable ■Elastic outer rim layer that will deflect and distribute point load ■Design needs to be as open as possible to allow regolith resistance

6. Methods: Materials ●Solution to clogging and coating of lunar regolith ○NASA and n-gmat, a nano-materials company has produced a coating ■Made from the lotus flower that has self- cleaning properties ●Possible use of adhesive in place of rivets ○Masterbond Supreme 10HT adhesive has a temperature range of -269 to 204 degrees Celsius ■NASA approved for low outgassing

7. Material Selection ●6xxx series alloys ○contain magnesium and silicon and these alloys have a good balance of corrosion resistance and strength ●Examined Aluminum 6061 T6, 6063 T6,and 6066 T6 ○evaluated strength, corrosion resistance, malleability, cost, and operation temperature tolerances ●Aluminum alloy 6061 T6 ○reasonable yield strength, relative low cost, and good corrosion resistance

8. Monarch Wheel Mark III ●Outer Layer ○An offset pattern of kidney shaped springs form a layer meant to absorb large point loads. ●Inner Layer ○A series of five spring loaded hinged spokes for a larger scale deflection, such as that from a large rock, allowing the tread to contact more surface

9. Traction ●Gecko tread ○Independent spring mounted treads ■improve traction and the wheels handling of point loads ■rhombus shape gives lateral and longitudinal grip

10. Methods: Testing ●Impact testing ○Impact testing on scaled models ○“Real-world” testing of prototypes ■Wheels mounted on to a pickup truck and driven over various surfaces simulating those of the moon ●Compression testing ○Point load testing of vehicle components ■placed between two conical steel platforms and compressed until failure occurs ○Spring testing ■tested and evaluated so as to relate the springs linear k value to torsional and bending k values

11. Methods: Testing ●Traction testing ○Lateral and longitudinal slip conditions ○Control and slip tests will be conducted using scaled replicas at 1/5th scale of the designs over three surfaces ■ a regolith simulant, a rocky surface, and a mixture of the two ○The tread pattern will be tested using a remote control vehicle ○A dynamometer will be used to measure torque required for slip

12. Expected Budget ItemAmount Gas$50.00 Mileage (estimated)$50.00 CNC work$0 Hub Material$150.00 Regolith$0.00 Metal Concepts - Rear Wheels$1,200.00 Miscellaneous$350.00 Total$1,800

13. Bibliography [1]D. V. Margiotta, W. C. Peters, S. A. Straka, M. Rodriguez, K. R. McKittrick, and C. B. Jones, "The Lotus coating for space exploration - a dust mitigation tool," in Optical System Contamination: Effects, Measurements, and Control 2010, 2-5 Aug. 2010, USA, 2010, p. 77940I (7 pp.). [2]D. Cao, A. Khajepour, and X. Song, "Modeling generalization and power dissipation of flexible-wheel suspension concept for planetary surface vehicles," Vehicle System Dynamics, vol. 49, pp. 1299- 1320, 2011/08/01 2011. [3]M.Abdel-rahman, A.Ahmed, E.Badawi, “Testing Natural Aging Effect on Properties of 6066 & 6063 Alloys using Vickers Hardness and Positron Annihilation Lifetime Techniques,” Defect and Diffusion Forum, Vol. 303- 304, no., 107-112, Jul 13, 2010.

14. Questions?