Integration of Fluid Sloshing Models with Complex Vehicle System Algorithms

Fluid sloshing is the motion of a liquid in a container subjected to forced oscillations and occurs in a moving container which is not fully filled. One industry which is significantly affected by fluid sloshing is freight transportation – an increase in demand for crude oil and other hazardous materials (HAZMAT) has in turn increased the number of highway and railroad vehicles transporting these materials. Fluid sloshing can have a significant effect on vehicle dynamics, especially in curve negotiation and traction and braking scenarios. It is clear that thorough understanding of this complex phenomenon is necessary in order to design safe and reliable vehicles. While many approaches have been used to model fluid sloshing, such as discrete inertia, discrete element, and computational fluid dynamics models, each has drawbacks which limit its scope of application. Finite element analysis (FEA), however, addresses many of these shortcomings by using a general, physics-based approach. One objective of this thesis is to integrate high-fidelity finite element (FE) fluid sloshing models with complex multibody system (MBS) highway and railroad vehicle algorithms in order to study the effect of fluid sloshing on vehicle dynamics and stability. Additionally, the effect of fluid sloshing on the coupler forces of railroad vehicles during braking scenarios will be investigated, including the efficacy of electronically-controlled pneumatic brakes. The standard definition for the centrifugal force will also be assessed and it will be shown that it is inadequate for describing the outward inertia forces of flexible bodies. Finally, fluid sloshing models based on two different FE formulations will be compared in order to assess their ability and efficiency in accurately capturing the fluid sloshing phenomenon.