Improving Crashworthiness of Railroad Rolling Stocks With New Generation Shock Energy Absorbers

Abstract

This paper describes the results of quasi-static and dynamic tests of a new shock energy absorber (SEA) capable of high energy absorption while limiting peak dynamic force magnitude in the event of an impact or collision. The SEA utilizes the unique reversible phase transition behavior of Ultra High Molecular Weight Poly-Ethylene (UHMWPE) material under pressure. A prototype drop hammer test confirmed the device’s high energy absorption as well as high damping capabilities at a relatively high deformation rate. The results of the test were used to calibrate a finite element (FE) model that enabled scalability of the SEA for practical applications. Preliminary design and FE simulations were made under a Federal Railroad Administration (FRA) sponsored program toward using a set of SEA as a part of a crash energy management (CEM) system to improve locomotive crashworthiness. The main objective of the program was to prevent locomotive override in the event of an inline collision with a hopper car consist at a closing speed of 30 mph. The FE model, without CEM, was validated to a previously performed full-scale locomotive crashworthiness test at Transportation Technology Center, Inc. (TTCI), Pueblo. The FE simulation results with added CEM system showed successful prevention of locomotive override up to 32.1 mph collision speed. Further scope of using suitably tailored SEA units as buffers to the ends of passenger coaches and tank cars with the objective of enhancing their crashworthiness is discussed.