HYSTERESIS OF NON-LINEAR VEHICLE VIBRATING SYSTEMS INDUCED BY DAMPING

Abstract

Dampers are usually built into the vehicles not in vertical position. This method of in- corporating 'under angle' is primarily verified by the demand of increasing the transversal stability of shafts. Shall α0 be the angle of damper to the vertical. Because of the use of α0 = 8°- 40° angle in the suspension system, a damping force characteristic different from the actual member characteristic prevails. In the literature dealing with vehicle swinging, the different angles of the damper to the vertical are not considered in the recalculation of the damping force characteristic. In the investigation to be introduced, the vertical damping force is, as per the above facts, a function of two variables depending on the relative displacement and the relative velocity. In this case even the damper of linear characteristic looses its linearity because of its hysteresis (see Fig. 1). Taking into consideration real vehicle parameters, the suspension systems of rigid axle and those of swinging lever are investigated separately. The excitations are of two types, too, namely purely sinusoidal and real stochastic road profiles. Taking into consideration the various speeds of vehicles and the various road con- ditions, the effect of hysteresis must not be neglected first of all at rigid axles in case of α0 > 30° at inferior road conditions and at higher speed, keywords non-linear vehicle vibration, damping.