Influence of link suspension characteristics variation on two-axle freight wagon dynamics

Abstract

The link suspension is the most prevailing suspension system for freight wagons in central and western Europe. Link suspension systems have strong non-linear characteristics including a hysteresis loop. The loop exhibits usually three characteristic sections with different tangential stiffnesses. The actual contact geometry of the links and end bearings has a significant influence on the characteristics. By wear in ordinary service, the contact geometry changes considerably, thus causing the characteristics to change. In summary, it appears that the link suspension characteristics are very sensitive to several factors, being hard to control in the real world of freight wagon operations. The various stiffnesses and hysteresis loops are found to have a strong influence on the ride qualities of vehicles. This paper presents non-linear multibody simulations investigating these matters. As long as the characteristics cannot be controlled within closer limits than found in this study, there is a strong need for the sensitivity analysis to be made, both in predictive multibody simulations of vehicle dynamics as well as for verification and acceptance tests.

Keywords:

• Freight wagon
• Link suspension
• Dynamics
• Ride quality
• Simulation
• Test

Acknowledgements

The authors gratefully acknowledge the financial and personal support from the Swedish National Rail Administration (Banverket), Green Cargo and Interfleet Technology (Sweden) for making this research possible. The support from KTH is also acknowledged.