Development of a structural optimization procedure for tramway vehicles and carbody architecture innovation through composite structures

Nowadays, due to environmental pollution caused by CO2-emissions, a global transition to electricity is taking place within railway industry. Lightweight design of railway vehicles could allow to reduce the power required during their operation conditions. Optimization processes, especially dynamic optimization approaches, are not widely used for designing of railway vehicles. In addition, in recent years, with the aim to increase weight reduction, sandwich structures were commonly introduced in the carbody structure. However, almost always they did not have any structural functionality. The present paper proposes the modelling and dynamic size optimization of a new roof assembly of a tramway vehicle including a sandwich structure. A new optimization procedure has been defined to support the traditional design approach. Subsequently, the roof assembly of the tram vehicle has been redesigned to allow the correct installation of the sandwich panel, fastened through a bonding joint. Encouraging results have been achieved in terms of mass saving and mechanical behaviour of the carbody shell. The developed methodology turns out to be a useful tool for supporting designers for obtaining a lightweight design. The innovative configuration of the roof assembly has shown promising performance in terms of mass saving, increasing of frequencies of vibration and costs.