Numerical investigation and experimental verification of the fatigue life of a cab suspension for an 8x4 truck

In this thesis, conceptual design studies of the swing arm of a commercial vehicle cab suspension system that provides the vertical springing movement of the cab were carried out and the effect of the damping characteristics used in the system on the fatigue life of the swing arm was investigated. In the conceptual design stage, the geometry of the swing arm was determined with the help of topology optimization using the static load conditions in the literature, and the material of the swing arm was determined according to the target safety factor as a result of the finite element analyses. Due to the problems that occurred during the manufacturing process of the swing arm and torsion bar assembly, a design change was made using the data obtained from the road tests. In the second stage of the study, a full vehicle model was established and as a result of the multibody dynamics analyses performed on the determined road track, dynamic loads acting on the swing arm were obtained for a total of five different vehicle models by using different shock absorber damping characteristics. Fatigue analyses were carried out using obtained dynamic loads and the effect of the different shock absorber characteristics on the fatigue life of the swing arm was obtained.