The Relevance of Non-Linear Dynamics on Railway Pantographs

The pantograph-catenary dynamic interaction is widely studied by computational simulations, which depend on accurate models to provide faithful results.In this paper, we particularly deal with the modelling of the DSA-380 pantograph.Firstly, experimental tests are conducted to evaluate the dynamic behaviour of the pantograph and the importance of the non-linearities in it.The non-linear behaviour is evidenced if a frequency response function changes when the excitation applied changes.In this work, we identify the nature of the non-linearities and the specific parts where they come from.Then, we create a model able to emulate the dynamics of the real pantograph with a simple but effective design.The model is a lumped mass model with a non-linear system for the pantograph head suspension, which includes geometric non-linearities and dry friction.The model is able to reproduce successfully the frequency response functions of the pantograph even though it is an uncomplicated model in which only the necessary elements are included.Besides the development of the model, this work also proposes an efficient strategy to integrate the dynamic equation with Coulomb friction, showing good performance even with slip/stick transitions.