Tyre Structural Mechanisms Influencing Shear Force Generation: Ideas From a Multi-Radial-Spoke Model

Following earlier work which introduced a planar multi-radial-spoke model for the computation of the shear forces developed by a tyre in a general state of steady motion, further development of the model is described. The influences of interposing between the tread elements and the wheel hub a notional tread base which is anchored to the hub by linear springs, giving it longitudinal, lateral and yaw flexibilities relative to the wheel are examined. Also, a new cross-stiffness effect, representing the stiffening of a spoke laterally when it is deflected longitudinally, is included. Tentative conclusions are reached regarding those aspects of the behaviour of a real belted radial-ply tyre which the model will reproduce and those which it will not mimic. Reasons for the limitations are suggested in the form of mechanisms present in the real case which cannot be included in the model without radical change to its form. This leads to suggestions for the construction of a physical model which will be very capable of matching a wide range of behaviour, while not being unnecessarily complicated. Such a model is expected to have advantages in terms of requiring minimal shear force measurements to identify its parameters, leading to significant economies in usage.