Optimization of the side paneling of an innovative railway vehicle with hydrogen propulsion

In a world where the change towards the use of green energy is increasingly current, mobility must also keep pace. For this reason, Alstom is developing a new type of products based on technological innovation in the energy sector. Among these new products there is the FNM-HMU project. It is an electric train belonging to the Coradia Stream family, intended for Gruppo FNM SpA’s regional railway services for the Brescia-Iseo-Edolo line. The energy necessary for the locomotion of this innovative vehicle is provided by the combined application of fuel cells and electric batteries. This is done to guarantee operability on a non-electrified line, where Diesel traction vehicles are still used today. Given the nature of the fuel cells, this project required the management and storage on board of a large amount of hydrogen, which is by right one of the main subjects of the imminent ecological transition. The reason why this thesis was developed arises precisely from this need. In fact, the management of high quantities of hydrogen has led to the need to foresee the birth of a specific carriage, whose architecture is an evolution of the Diesel one. Among the various innovations, there is also the definition of appropriate panels on the sides of this carriage. The discussion performed in this thesis is focused exactly on them, analyzing the most critical aspect of their design phase. The first aspect of the discussion is related to the tolerancing analysis. For this purpose, a complete study of all the dimensional and geometric requirements, relating to the panels and to all the other components with which they interface, was carried out. In doing this, proper stack-up analyzes were performed, taking care to define the appropriate design specifications. These prescribed specifications have been defined consistently with the most recent standards in the field of dimensional and geometrical tolerancing, such as the set of ISO-GPS Standards. The outputs of this first study were, therefore, the validation of some design choices or the modification of some components. Among these, the case of the lateral fixing brackets of the panel proved to be of particular importance. In fact, following the rejection of the initial design, it was necessary to completely redefine the geometry of these brackets. This has therefore given rise to the second part of the analysis carried out in this thesis. In detail, it was necessary to validate the new design proposed by means of an FEM analysis, in order to identify any structural criticalities. In addition to the tolerancing analysis, another aspect has been defined as critical. This is related to the accessibility towards a hydrogen sensor located inside the carriage from the outside. In fact, since this bracket must be calibrated periodically, proper inspection doors were provided on the panels. Therefore, firstly, a virtual simulation has been performed, to define the better location of the hydrogen sensor. Once the best proposal has been identified, a further analysis has been carried out. It involves a modal analysis to validate the sensor bracket and in the realization of a physical model to check the compliance of all the assumptions.