Cho Wing Solomon To
Date of this Version
Tzu Yu ,Tseng. "Dynamic Responses of Wheel-Rail Systems with Block Dampers." Thesis. University of Nebraska-Lincoln, 2016.
The wheel-rail interaction problem has been widely studied in the past few decades. In this problem, dynamic responses at the contact areas remain the central issue since they induce damage to the rail over time. In particular, the dynamic responses at the contact areas between the wheels and rails present difficulties in understanding and mathematical modeling. Even with the computer power one has today, its mathematical modeling employs the versatile numerical analysis method, the finite element method (FEM) remains a formidable challenge due to its extremely small contact areas and in turn the extremely high stress levels. In addition, friction at the contact areas is another challenge in the modeling. These extremely high stress levels and difficulties in modeling friction at the small contact areas lead to the simplified analytical and finite element (FE) models available in the literature. However, to-date, these simplified mathematical and computational models are far from satisfactory. Therefore, in the investigation reported here, simplified analytical and FE models are first studied in order to understand the parameters of the models and to provide a foundation for more detailed studies. In these simplified analytical and FE models, the wheels are treated as traveling point loads.
Subsequently, a more detailed FE model employing three-dimensional (3D) finite elements for the wheel and rail is studied while the computed results are compared with those of the same FE model but with the wheel replaced by the traveling point loads. In this model, frictions at the contact areas are considered. In parallel, the effect of block dampers on the dynamic responses at the contact areas is studied. Various configurations of attaching the block dampers to the rail are considered. Conclusions are then drawn from the accuracy and efficacy of replacing the wheels by traveling point loads, and the effect on the dynamic responses of added block dampers to the rail.
Advisor: C. W. Solomon To