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Lightweight primary structures for High-speed railway carbodies

In these case an approach completely different introducing a complete new concept and new
materials for the primary structures in railway sector, Peris (2017).
The goal of the work carried out as part of Shift2Rail is to develop lighter carbody shells which
make full use of the possibilities of composite materials including integration of functions. This
is linked to identifying the specific design principles, materials and manufacturing processes that
fulfil the requirements set in previous projects such as REFRESCO and Roll2Rail, in terms of material
properties, manufacturing cost and certification. To this end this plan envisages to develop a
carbody made of hybrid materials (mainly composites) in the primary structure that will achieve:

• Between 15 and 30% weight reduction.
• Energy savings in operation, resulting from the weight reduction.

• Improvements in maintainability, coming from new concepts.
• The introduction of a specific health monitoring process.
With today’s materials and manufacturing technologies, manufacturers of rolling stock are very
close to the border in terms of weight optimization (Molinari, 2016), so a change of concept in
the structure of the car is imposed in order to reduce the weight of the structure primary. This
objective is aligned with the objectives set in the H2020 to reduce the life cycle cost (LCC or
Life Cycle Cost) globally of rail transport and to increase the capacity of the rail sector.
The use of material different from metal has been proved in the aeronautic industry, where
composites are increasingly being used in structural parts after having passed all tests regarding
safety.

In conclusion lighter carbodies could be made with industrial processes, provided that adequate
joint methods are used and there is compliance with rail safety standards.

Different conceptual studies have been developed based on topology optimisation and structural/
acoustical calculation of materials and joints in order to lay the foundation for the designing
phase of Shift2Rail.
An example of the topology optimisation is shown in figure 2. The influence of the geometry
and location of the cut-outs in the weight of the structure was studied. For an urban model,
different configurations were analysed achieving a weight improvement of up to 20% in the case
of decreasing the width of the door 300mm (-15% in width). For a High Speed model, up to a
14% weight reduction was achieved when the service door is placed at the centre of the coach.
At the end of Shif2Rail project a full carbody demonstrator with a hybrid carbody will be
presented fulfilling the requirement of weight reduction mentioned before maintaining or
improving the current performance of the metallic primary structures in terms of safety,
durability and maintainability.

Figure 11. Topology optimisation for urban trains (left) and high speed trains (right)

International Congress on High-speed Rail: Technologies and Long Term Impacts - Ciudad Real (Spain) - 25th anniversary Madrid-Sevilla corridor 19