Materials with Improved Absorption of Collision Forces for Railroad Cars

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Materials with Improved Absorption of Collision Forces for Railroad Cars

A. Rabiei

The objective of this project was to examine the potential of Composite Metal Foams (CMFs) to improve the crashworthiness of railroad cars. Potential applications include the incorporation of CMFs into the structural members of passenger cars. Numerous efforts have gone into understanding the mechanical properties of metallic foams in general and CMFs in particular. While most of those studies have covered the properties of the material under a variety of low-speed loading conditions, this study extended the current knowledge by investigating CMFs’ behavior under high-speed loading rates to mimic the speeds at which passenger cars and trains travel. For this purpose, the project team first optimized the CMF processing techniques in order to enable the processing of large-scale and low-cost CMFs. Then a Split Hopkinson Pressure Bar was used to investigate the mechanical performance of composite metal foams under high-speed impact speeds of 13, 22, and 30 m/s (equal to about 30, 50, and 68 mph). The results showed that elastic modulus, strength and total energy absorption of CMFs under such loading rates is significantly higher than those under quasi-static (slow) loading. This makes CMFs even more attractive for application in collision protection of railroad cars or other vehicles.