Enabling the Optimisation of the Primary Suspension with Passive Components for an Industrial Railway Vehicle Model

The use of inerters in the lateral suspension of railway vehicles has been proven, in recent studies using lumped mass models, to provide benefits in terms of track wear and passenger comfort improvement. Validation of these enhancements using an industry standard simulation tool, which analyses realistic vehicle models with numerous degrees of freedom, is essential if the railway industry is going to adopt this new piece of technology. The problems associated with this, however, come in the form of large complicated numerical matrices, slow inversion times, and algebraic loops associated with the inerter’s acceleration dependence. The systematic investigation of candidate vibration absorber configurations is also problematic. To this end, this paper proposes a Location Matrix method of simulation which enables the optimisation of interchangeable suspension networks within large dynamic systems by the use of a Laplace to state-space transformation. This method, which can be applied to any dynamic system and needs only the knowledge of the base mass, stiffness and damping matrices, is validated using a low degree of freedom system, and it is found that for railway vehicles, optimisation on a linearised or semi-linearised model can be performed. Nonlinearities arising from the varying contact patch normal force mean that further investigation is needed before a full analysis can take place.