Rollover stability analysis of commercial semi-tanker trucks utilizing a trammel pendulum model to simulate fluid sloshing

Commercial vehicles that transport low viscosity liquid payloads are some of the most unstable vehicles on the highway. These vehicles have low rollover stability thresholds when performing lateral maneuvers, such as lane changes and constant radius turns, because of their high centers of gravity and the dynamic sloshing of their liquid cargo. The objective of this study was to develop mathematical models that could be utilized in MATLAB and implemented in real-time simulators to simulate the sloshing of low viscosity fluids in partially filled truck tanks to study the resulting semi-tanker truck rollover behavior.Various analytical and numerical methods have been used to study the dynamic effects of sloshing fluids. An effective way to mechanically model fluid sloshing dynamics is by utilizing a pendulum. In this study a trammel pendulum was chosen to simulate the fluid sloshing effects for partially filled vehicles as they exected lateral maneuvers. This study dealt specifically with elliptical semi-tanker trucks with tanks of different aspect ratios and different levels of fill however, this research can be extended to other liquid carrying commercial vehicles. To include the internal damping effects of the fluid in the sloshing model, Hamilton's principle as well as dimensional analysis was utilized. The trammel pendulum model's kinematic and dynamic effects were studied and verified against fluid sloshing dynamic results otained through finite element analysis.Once the mathematical model representing fluid sloshing was developed, the sloshing model was coupled to a two-dimensional rigid body semi-tanker truck lateral dynamics model to determine the rollover stability of commercial semi-tanker trucks when performing double lane change and constant radius turn maneuvers. The rollover stability threshold of the rigid body vehicle model ranged from 0.2 g's -- 0.8 g's, depending on the lateral maneuver and the tank aspect ratio being considered. These results agreed with the rollover stability threshold data reported in commercial vehicle rollover literature and researh. The rollover stability thresholds were predicted within an acceptable level of accuracy of +/-12%.The fluid sloshing model and the two-dimensional rigid body vehicle model have the potential to be expanded and developed into more comprehensive models that includ more complex properties, such as tank baffling, tire dynamics and vehicle suspension kinematics. These expanded models could then be implemented into the Advanced Mobile Operations Simulator II (AMOS II) vehicle simulator located in the Man-Machine Systems Laboratory at Binghamton University for driving training and other research.