Lunar Wheel

1. MAE 435Spring 2014 Seth Hughes Robert York James Taylor Alicia Najor Shannon Green Trucmy Nguyen David Palmer Lunar Wheel

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

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, 20 10, 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?