Prediction of tread block forces for a free-rolling tyre in contact with a smooth road

This paper presents a model for the contact mechanics of tread blocks on a free-rolling pneumatic tyre, of a complexity intermediate between sophisticated 3D finite element (FE) analyses and simple brush models. The model is able to capture the essential physics of the contact while being sufficiently simple to be incorporated into dynamic tyre models, such as can be used to predict hub forces. The tread blocks are represented by a ‘brush-type’ spring model, taking into account the geometry of the contact and shear deformations of the tread. The rubber is represented as a linear viscoelastic material. The spring model is found to give similar normal and shear force predictions to a more sophisticated finite element analysis undertaken in the paper, both for tread blocks mounted on a deformed tyre belt (with the geometry taken from measurements of a loaded tyre) and for blocks on a rigid cylinder, matching the geometry of a small-scale rolling contact test rig. Predictions compare reasonably with measurements on the rig of tread block normal and tangential forces.