Dynamics and Strength of Circular Tube Open Wagons with Aluminum Foam Filled Center Sills

The study deals with an application of aluminum foam as an energy-absorbing material for the carrying structure of a rail car. The material is particularly recommended for circular tube carrying structures. The authors conducted mathematical modeling of dynamic loads on the carrying structure of an open wagon that faces shunting impacts with consideration of the center sill filled with aluminum foam. It was established that the maximum accelerations on the carrying structure of an open wagon were 35.7 m/s(2), which was 3.5% lower in comparison with those for a circular tube structure without a filler. The results obtained were proved by computer modeling. The strength of the carrying structure of an open wagon was also calculated. It was established that aluminum foam applied as a filler for the center sill decreased the maximum equivalent stresses in the carrying structure of an open wagon by about 5% and displacements by 12% in comparison with those involving the circular tube carrying structure of an open wagon without a filler. The natural frequencies and the oscillation modes of the carrying structure of an open wagon were defined. The designed models of the dynamic loading of the carrying structure of an open wagon were verified with an F-test.