LUNAR WHEEL MAE 435 Spring 2014Seth Hughes Robert York James Taylor Alicia Najor

Shannon Green Trucmy Nguyen David Palmer

Gantt Chart

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

Introduction

● Improvements upon last year’s wheel○ Replace welds with aerospace

adhesives ○ Handle point loads better○ Improve traction

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

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

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

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

Traction● Gecko tread

○ Independent spring mounted treads

■ improve traction and the wheels handling of point loads

■ rhombus shape gives lateral and longitudinal grip

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

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

Expected Budget Item Amount

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

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.

Questions?