Finite Element Analyses of Side Impacts to DOT-113 Surrogate Tank Cars with Water and Liquid Nitrogen
On June 11, 2021, the Federal Railroad Administration (FRA) conducted a side impact test on a surrogate DOT-113 tank car filled with water at the Transportation Technology Center (TTC) to (1) evaluate its performance under dynamic impact conditions and (2) provide data for the verification and refinement of a computational model. The tank car was filled with water to approximately 82.4 percent of its volume, sealed, and pressurized to 50 psig. The tank car was impacted at 17.3 mph by a 297,200-pound ram car with 12-inch by 12-inch ram head fitted to the ram car. The impact caused significant deformation of the tank, but did not result in puncture of the inner or outer vessels. The Volpe National Transportation Systems Center (Volpe) performed finite element (FE) computational modeling to estimate the overall response of the tank to the impact and achieved excellent agreement with the test results. The next side impact test took place in May 2021 with a surrogate DOT-113 tank car filled to 95 percent of its volume with liquefied nitrogen and pressurized to 50 psig. As this was the first side impact test of a tank car filled with a cryogenic liquid, Volpe conducted a series of pre-test FE modeling studies to estimate the response of the surrogate DOT-113 tank car filled with LN2. The computational studies focused on the (1) thermal contraction of the inner vessel, (2) physical behavior of cryogenic gaseous nitrogen, and (3) physical behavior of liquid nitrogen.