In-house instrument development and updated classical equations for compacted snow characterization

Abstract

Testing and evaluation of commercial passenger car and truck tires for severe snow usage are performed on compacted snow tracks based on the ASTM F1805-20 standard. The snow track is characterized for these tests using the CTI penetrometer. Evaluating the compactness of the snow track as an index number is helpful, but it does not provide information that can be useful from a simulation/modeling perspective.

In this work, a new device was developed that was inspired by the ‘Russian snow penetrometer’ to help evaluate the compressive and shear properties of snow. It was found that the classical methods of analysis used for Rammsonde penetrometers and Clegg hammers had some discrepancies that partially stem from assumptions made in their formulations. This work proposes modifications to the equations thereby improving their outputs to align with a more physics-oriented approach. The assumptions in the formation of classical equations are not incorrect but may not be completely accurate for cones with a higher surface area to base area ratio.

Future work could be assessing the accuracy of the devised equations in different terrain conditions and a sensitivity study to identify critical cone angles in different conditions.