Wheel–rail dynamic of DMU IC4 car for DSB: modeling of the secondary air springs and effects on calculation results

Abstract

This paper deals with AB experience about dynamics simulation, focusing on the IC4 car modeled in a multibody system environment. The vehicle is made of four coaches supported by three kinds of bogies. Three different modeling topologies of secondary air suspension were compared for dynamics behavior. The first model of air spring was the ‘equivalent’ spring model, an equivalent spring extra-polated from the natural bouncing frequency of the air spring. The second model was linear spring, a component force element which only generates forces, not torques. The thermodynamic behavior of the air spring was modeled as a linear spring–damper system. Both equivalent and ‘linear’ were merely passive elements. The last force element was developed to cover the entire physical description of air spring. A feedback control on the coach roll was considered due to the leveling pneumatic system. CPU time and accuracy of results were evaluated for different target analysis.