Page 268 - 360.revista de Alta Velocidad - Nº 5

Álvarez, Fernando. Balmaseda, Lucía. Gallego, Inmaculada. Rivas , Ana. Sánchez-Cambronero, San

3. Numerical model

3.1 Description

The numerical model presented here consists of a three-dimensional Finite Element model and
fully parameterized, that is, it allows the user to directly modify the geometric properties that
define the railway track section as well as the mechanical and geomechanical characteristics
that define the behaviour of the elements of the superstructure of the track and the granular
layers of the infrastructure. The tool used for the numerical modelling is commercial software
ANSYS® Mechanical APDL 17.2, which requires the use of external programming codes or through
the direct use of the interface.
With regard to the same, only the most relevant elements of the superstructure are modelled:
rail, bearing plate, sleepers and ballast; and infrastructure layers: subballast, formation layer
and embankment or subgrade. In this way, the finite element model acquires the form shown in
Fig. 1, simulating half of the section of track as a single track.

Fig. 1. General view of the numerical model and its mesh.

3.2 Geometry and material properties

For the definition of the geometry and the elements that form the section of railway platform
have been used the different recommendations and methodologies of modelling collected by
the different mentioned above.
With regard to the elements of the track superstructure: UIC60 rail, bearing plate and
sleepers; These have been modelled with equivalent geometries of parallelepiped volumes
by threedimensional elements of 20 nodes and that, together with the adjustment of the
mechanical properties of materials (Gallego, 2012), it is possible to model with more accuracy
the structural behaviour of these in the different situations of load.

266 360.revista de alta velocidad