Model Development and Validation of Special Purpose Trucks for Analysis of Maximum Loads and Forces on Various Hard and Soft Terrains

The purpose of this study was to determine whether two special purpose vehicles could push a Medium Girder Bridge (MGB) under various conditions. There are important tasks related to pushing and supporting a load that must be performed and knowing the conditions where this can be done is of great import. This analysis was done by building a multibody dynamics model of both trucks using the Vortex program created by CM Labs. The vehicle models were created using known data from datasheets as well as by taking measurements and performing physical tests on the vehicles themselves. Physical testing, where the drawbar pull force was determined on some surfaces was also done to help validate the models. Additionally, tire testing was done to determine some of the tire parameters important in the model. Various terrains, including asphalt, gravel, ice, snow, muskeg, and several soils were also produced in Vortex using terrain parameters from previous studies. The maximum loads the vehicles would have to deal with to deploy the bridge were measured during real bridge deployments and this information was used to determine through simulation whether the vehicles could perform under the measured loading conditions on each of the surfaces.