Study of Prestressed Multi-leaf Spring Behavior in Terms of Tandem Bogie Layout with Utilization of FEM

This paper deals with a problematic of multi-leaf spring modeling. Many vehicles are being equipped with independent suspension for its unquestionable advantages over dependent. Still, for medium or heavy trucks, designed for off road conditions, dependent multi-leaf spring is preferred in some cases. Further enhancement of the mobility can be achieved with tandem bogie layout. For the behavioral study of the dynamic motion of the aforementioned vehicles, a great number of the inputs is required. Mainly from the suspension components, since they are in direct contact with the road surface. Some of them can be omitted, but others are crucial for the achievement of adequate value of correlation coefficient between the proposed dynamic model and its experimental validation result. One of those crucial inputs is the behavior of multi-leaf spring under the certain circumstances. The behavior is mainly set by the stiffness characteristic (force-displacement curve) and the phenomenon called hysteresis. If the characteristic is unknown and the only information about the multi-leaf spring are its dimensions and materials, the solution lays within the utilization of FEM. With the results from the simulations, a stiffness characteristic can be constructed. Therefore, the paper is divided into following steps: firstly, the brief introduction along with a state of the art was carried out. Secondly, a simple model was created and hysteresis was observed. Then the leaves were prestressed, in a factory way of assembly, and the force-displacement characteristics were conducted for a various values of coefficient of friction between the leaves. Lastly, the utilized method was summarized and evaluated.