Investigation of the effects of inter-leaf friction on leaf spring damping characteristics via multi-body simulation

Leaf spring is one of the oldest components used in the suspension system of the ground vehicles due to its high load capacity and cost efficiency. Leaf springs still have wide usage in today's vehicles, mostly on the load carrying ones such as trucks, vans or pick-up trucks. Computer aided engineering methods are very common in automotive design engineering. The developing technology enables engineers to simulate accurate models instead of testing and improves the design process. The wide usage of the leaf spring in vehicles, makes this component a focus for computer aided engineering models. In order to create accurate models of the leaf spring, characteristics of the leaf spring in the desired study should be well-known. One of the characteristics of the multi-leaf springs is the friction between the leaves. Frictional contact on leaf springs has several effects on the system. One of the most obvious effect is the energy dissipation due to relative motion of the adjacent leaves. This directly acts as a damping on the vehicle suspension system. Friction also cause dynamic rate changes of the leaf spring. One of the disadvantages of the leaf spring inter-leaf friction is noise and surface wear. In previous studies, some methods are suggested to reduce the friction in leaf springs in order to eliminate the disadvantages. The advanced necessities in automotive industry and the developed technology also shows its effects in leaf spring designs. The newer leaf springs have more complex geometries and less leaves when compared to the older ones in order to optimize the durability and NVH behavior. However the inter-leaf friction in multi-leaf springs is still an issue that has to be considered. Friction in leaf-springs were studied in many aspects until now. This study focuses on to create and accurate multi-body simulation model of the leaf spring and the study of frictional effects on its vertical behavior. In order to obtain vertical behavior of the suspension with leaf spring, multi-body simulations are conducted on quarter-car and leaf only setups.