Experimental Studies on Traction Concepts: Endurance and Obstacle Testing

This paper presents experimental endurance results of three undergraduate-designed and built soft soil traction concepts. An experimental approach was chosen due to the limitations of current analytical models of traction on soft soils. The use of analytical models requires detailed understanding of the geometry and mechanics of the tread not readily available. Experimental methods do not require this advanced understanding and provide rapid and realistic results. Building on previous research which showed that the use of high density foam and concave geometry increased the traction performance of a tire in sand, three new concepts are prototyped with a focus on exploring endurance and survivability in aggressive testing. These prototypes employed the use of thinner foam than was previously studied, bed liner, and a combination of Kevlar and bed liner (“Kevliner”). The prototypes were tested in a rotating trough filled with sand where each tread prototype was subjected to distance and acceleration tests with and without a rock obstacle. The damage incurred by the prototype and the percentage of slip between the tire and the trough was recorded during each test to assess the performance of each prototype. Analysis of the slip data collected showed that there was little variation in traction between the three prototypes. This was expected as each concept was based on similar working principles for traction. Therefore, more significance was placed on the physical damage sustained by the prototype to evaluate performance than the slip. The Kevliner prototype proved to be the highest performing prototype. It was the only prototype to complete the entire testing suite. The thin foam and bed liner prototypes both sustained severe damage during an acceleration test with the rock obstacle (the fifth of the six tests). The success of the Kevliner prototype can be attributed to the added strength and durability provided by the Kevlar.