This paper describes further development of a planar multi-radial-spoke model which computes the shear forces developed by a tyre in a general state of steady motion. The influences of interposing a notional tread base between the tread elements and the wheel hub are examined. This notional tread is anchored to the hub by linear springs, giving it longitudinal, lateral and yaw flexibilities relative to the wheel. A new cross-stiffness effect, representing the stiffening of a spoke laterally when it is deflected longitudinally, is also 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. Suggestions are made about 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.
Samenvatting