MODELING AND TESTING SNOW PLOWING FORCES ON TRUCKS

The forces involved in ploughing snow have been investigated to a limi ted degree with some basic analytical approximations formulated in the past 60 years. This paper explores the validity of these previous mod els using a known plough blade geometry and revised snow flow model. T he approximations derived by Croce, Mellor and Kaku are presented as w ell as the common snow flow model currently in publication. Plastic wa ve speeds in snow ale calculated in the lateral and longitudinal direc tions. The flow of snow in front of and across the mouldboard of a plo ugh blade is expanded from the current model to include compressive, s hear and turbulent zones in front of the blade. The force diagram for a plough truck equipped with a wing blade is developed. Experimental t esting was conducted on a plough truck equipped with a wing blade, wit h the forces on the blade recorded during testing. The forces on the b lade were compared to Mellor's and Kaku's models with the conclusion t hat current models are not valid for low speed ploughing. The previous models vary the force in proportion to the square of the velocity and the testing results show a linear relationship between the forces and speed. This linear relationship shows that snow acts as a solid rathe r than a fluid during low speed ploughing. It is also shown that previ ous models do not correctly account for blade geometry such as the win g blade geometry in the experimental tests.