Experimental Analysis of the Effects of the Variation of Drawbar Pull Test Parameters for Exploration Vehicles on GRC-1 Lunar Soil Simulant

A drawbar pull (DP) test procedure was developed at the NASA Glenn Research Center (GRC) for testing and developing designs for off-road vehicles. The motivation was to develop a procedure that would produce repeatable results and could be replicated by other researchers. While developing the test methodology, it became apparent that there was a certain degree of scatter in the results among identical tests. In order to characterize the disparities, an experimental study was conducted consisting of systematically varying specific test parameters. The selected performance metric was the DP-TR (travel reduction) relation. The selected parameters were: 1) the starting terrain condition, 2) the distance traveled by the vehicle under an applied, constant DP force, and 3) the density of the prepared terrain. Respectively, these parameters were selected to observe: 1) how differences in the starting area, or "launch pad," would affect the resulting performance of a test, 2) if a steady-state region of performance exists and how does performance change with the distance traveled, and 3) the relationship between prepared terrain density and performance. These experiments were conducted in a dry, granular, cohesionless, silica based soil called the GRC-1 Lunar Soil Simulant. The results of these studies were that the variations in both the starting terrain condition and the distance traveled did not significantly affect performance. The relationship between performance and terrain density was that only in a region of low density was the TR constant; subsequently, the TR decreased steadily with increasing density.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2011

Author dc:creator

• Woodward, Adam Charles

Chair dc:contributor.committeechair

• Sandu, Corina

Committee members dc:contributor.committeemember

• Taheri, Saied
• Ferris, John B.

• Terrain Density
• Travel Reduction
• Lunar Soil Simulant
• Drawbar Pull
• Terrain Preparation

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-06062011-094609

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/33457