Balint Szabo Budapest University for Technology and Economics Faculty
for Transportation Engineering Department for Automobile Engineering,
MULTI-BODY WHEEL MODEL DEVELOPMENT FOR SIMULATING THE TIRE DEFORMATIONS
DURING LONGITUDINAL AND LATERAL SLIDING
Road vehicles are equipped with pneumatic tires for two main reasons.
First, due to their elasticity the tires can absorb the high frequency
vibrations; the second purpose is the adhesion. To analyse the motion
of a tired vehicle, this deformation effect must be considered. If we
are only interested in longitudinal and lateral motions and deformations,
the vertical effects can be ignored. The simplest solution is to model
the wheel as a multi-body system. The wheel rim is a rigid body, which
has mass and inertia around its vertical axis. Although the tire is a
continuum, it can be separated along its circumference. The tire is represented
by tire elements, which are mass points. These tire elements are connected
to each other and to the wheel rim with springs and dampers. Friction
force arises as well on those tire elements which are in the contact
patch; therefore these elements are gripped on the ground. If we know
all the spring forces, damping forces, friction forces and outer forces,
then writing up the differential equations of the bodies, we are able
to compute the motion functions using an appropriate numerical solver.
With the above described method we can simulate the wheel sliding motion
due to different forces and torques acting on it. Both the trajectory
of the wheel and the deformation of the tire can be plotted and analysed.
Various simulations can be made with different friction coefficient,
mass, or stiffness.