ABSTRACT
A numerical calculation method of the vibrations caused by uneven road surfaces is dealt with for three-dimensional multi-axle vehicle models.
Measurements are quoted to illustrate that the lateral elasticity of the tyres should not be neglected. For reasons of numerical convenience (the corresponding cross-spectra are then zero), the unevennesses of a road-surface cross-section, determined by measurements, are described by symmetrical (bounce excitation) and antimetrical (roll excitation) components. With appropriately matched vehicle coordinates, the movement equations can then be de-coupled into two equation systems.
The computing example used is a car with a front McPherson axle and a rear beam axle. It is demonstrated that with an anti-roll bar it is hardly possible to achieve any further vibration improvements. If fitted additionally with a damper, however, the anti-roll bar can noticeably reduce the dynamic wheel loads and side forces of the associated axle, and transverse and yaw vibrations of the body, notwith-standing that this is at the expense of body roll acceleration. It is possible to make improvements without loosing comfort only if a linkage compensates the roll vibrations of the axles one against the other to eliminate reactions.
