Parameter study for an energy efficient suspension for a rail vehicle prototype

Abstract: The push for sustainability in all parts of our society has never been as big as it is currently. One project that aims to produce sustainable innovation in the railway industry is the Delsbo Electric competition where some of the world’s most energy efficient vehicles compete. A dominant design has arisen in the competition which means that competitors must seek innovative avenues of development in order to find an edge over the competition. One such avenue has been to use composite material in construction to decrease mass and therefore increase energy efficiency. The KTH Delsbo Electric team views the suspension system as one such avenue that has the potential to improve efficiency. This project is a study into the dynamics of rail vehicles and especially rail vehicle suspension systems. Using a vehicle modelled in an MBS software a parametric study is conducted with the goal to optimize the energy efficiency through an iterating process by only varying the stiffness and damping parameters for the suspension system. Through the iterating process, it became clear that some parameters are more closely linked to different parts of the vehicle behavior than others. The energy efficiency is closely linked to the stiffness in the suspension, especially in the longitudinal direction. The ride comfort was found to be very much linked to the damping parameters. This made it possible to tune the stiffness and achieve high energy efficiency and then adapt that setup to gain better ride comfort. This study also concludes that the vehicle derailment factor (L/V) is inversely linked to energy efficiency. Therefore, an energy efficient vehicle is less likely to derail. The result of this thesis is a setup of energy efficient parameters that will lay the groundwork for a project to design and manufacture a suspension system with the outlined parameters.