Off-road tyre modelling III: effect of angled lugs on tyre performance

Abstract

Satisfactory analysis of the off-road tyre performance parameters of agricultural vehicles depends on the accurate prediction of the forces between off-road tyre and terrain. The normal and shear stresses at the interaction between wheel and soil determine these parameters. This paper presents a prediction method to estimate the forces under angled lugs on a deformable surface. The normal and tangential forces generated at the interface between an off-road tyre with angled lugs and terrain was estimated by using the modified multi-spoke tyre model. This model was extended to predict the pull, lift and lateral forces including the effect of angled lugs. A comparison between the forces generated between the terrain and the off-road tyre with straight lugs and with angled lugs was made. The influence of different parameters such as soil hardness, soil deformation modulus, longitudinal wheel slip, lug height and lug angle on the angled lug forces was studied. A computer program using MATLAB software was developed, and the results were presented in the form of distribution of angled lug forces along the tyre contact length. The results indicated that the angled lug forces decreased as the soil deformation modulus and soil hardness increased. angled lugs provided higher lateral force and lower tractive force than straight lugs. The angle of lug has a significant effect on the forces of the angled lugged tyre. ©