Compacted Snow Testing Instrumentation and Parameters Collection for Tire-Snow Studies
Virginia Tech, USA
Director of the Terramechanics, Multibody, and Vehicle Systems (TMVS) Laboratory
Abstract
Driving in winter conditions is extremely challenging. One of such scenarios is driving on compacted snow on roads. Snow is a complex material that is difficult to characterize especially due to its high compressibility and temperature-sensitive nonlinear viscoelasticity. While snow mechanics has been intensively investigated by avalanche and army researchers for decades, very few research studies have been conducted for compacted snow. In the USA, the standard ASTM F1805 is employed for the evaluation of winter tires which can be used in harsh conditions like ice and snow.
This talk will briefly introduce prior efforts performed for the measurement of snow properties. Analysis using regression models and principal components is performed to understand the extent to which specific measurements related to snow affect the traction of the tire. Our study found that the compressive and shear properties of snow contribute over 90% to the variation in the traction coefficient of a tire when evaluated on a compacted snow domain per ASTM F1805.
In order to collect relevant information on the compacted snow material properties, in our laboratory we developed a device for measuring the compaction and shear properties of snow. The device was manufactured in-house and tested at the Smithers Winter Test Center to benchmark against existing devices available commercially. Current work to improve the capabilities of data collection for compacted snow is on-going in the lab, as well as modeling of compacted snow and tire-snow modeling.
