THE PREDICTION OF TRACTIVE PERFORMANCE ON SOIL SURFACES

A new approach to the traction prediction equation is described. The p roposed equation uses the soil deformation modulus and physical proper ties of agricultural tyres as parameters. The novel features of this a pproach include the assumption of a non-linear shear stress distributi on and change in the value of soil deformation modulus with the normal stress. A model which suggests a relationship between the contact pat ch area and the soil deformation modulus is also introduced. The predi ction equation was compared with the widely used Wismer and Luth equat ion and measured data obtained by Wittig. The proposed approach result s in an improvement over Wismer and Luth in the prediction of traction and it also involves minimal testing.