The operational properties of the road vehicle are the result of the dynamic
interaction of the various components of the vehicle structure possibly including
modern control elements. A major role is played by the pneumatic tyre.
“The complexity of the structure
and behaviour of the tyre are such that no
complete and satisfactory theory has yet been propounded. The characteristics
of the tyre still presents a challenge to the natural philosopher to devise a theory
which shall coordinate the vast mass of empirical data and give some guidance
to the manufacturer and user. This is an inviting field for the application of
mathematics to the physical world”.
In this way, Temple formulated his view on the situation almost 50 years
ago (Endeavor, October 1956). Since that time, in numerous institutes and
laboratories, the work of the early investigators has been continued. Considerable
progress in the development of the theory of tyre mechanics has been made
during the past decades. This has led to better understanding of tyre behaviour
and in its role as a vehicle component. Thanks to new and more refined
experimental techniques and to the introduction of the electronic computer, the
goal of formulating and using more realistic mathematical models of the tyre in
a wide range of operational conditions has been achieved.
From the point of view of the vehicle dynamicist, the mechanical behaviour
of the tyre needs to be investigated systematically in terms of its reaction to
various inputs associated with wheel motions and road conditions. It is
convenient to distinguish between symmetric and anti-symmetric (in-plane and
out-of-plane) modes of operation. In the first type of mode, the tyre supports the
load and cushions the vehicle against road irregularities while longitudinal
driving or braking forces are transmitted from the road to the wheel. In the
second mode of operation, the tyre generates lateral, cornering or camber, forces
to provide the necessary directional control of the vehicle. In more complex
situations, e.g. braking in a turn, combinations of these pure modes of operation
occur. Moreover, one may distinguish between steady-state performance and
transient or oscillatory behaviour of the rolling tyre. The contents of the book
have been subdivided according to these categories. The development of
theoretical models has always been substantiated through experimental evidence.