The computational toolbox CANDY is aimed to the simulation of pantograph – catenary dynamic interaction within different levels of complexity and purposes. Indeed, it includes a simple time-varying lumped model, a modal reduction model, a FE based model, a coupled modal-FEM formulation and finally and ad hoc FEM with a moving mesh able to follow the pantograph along the contact wire.
Regarding the last abovementioned model, it is based on co-rotational finite element formulations: beam elements for the contact and messenger wires but truss elements for the droppers. Although the behaviour of these elements is closer to cables, the inclusion of bending efforts especially in the contact wire allows obtaining much realistic results. These have been checked and validated against the requirements of the European Standard EN 50318 besides the international benchmark for the pantograph – catenary interaction.
Finally, taking advantage of the flexibility that an own tailored approach provides both for the inputs and the outputs. Firstly, it includes an a-Taylor–Hughes time integration scheme, which allows having different time integration schemes and time steps, from the ß-Newmark family to the Hilber-Hughes-Taylor (HHT) method. Secondly, the code has been enhanced with a moving mesh procedure in order to reduce the computational effort of the simulations. And thirdly, a pioneer module for the stochastic generation of wind gusts has been developed to forecast the probability of loss of contact or dewirements due to wind loads.