Technical Reports

Alternative Occupied Volume Integrity (OVI) Tests and Analyses

  • 28
  • Oct
  • 2013
AUTHOR: Authors: Michael Carolan, Benjamin Perlman, David Tyrell
SUBJECT: Facilities & Test Equipment, Occupant Protection, Crashworthiness - Passenger Equipment, Passenger Rail
KEYWORDS: Occupant volume integrity, testing, finite element analysis, passenger equipment, crashworthiness
ABSTRACT: FRA, supported by the Volpe Center, conducted research on alternative methods of evaluating occupied volume integrity (OVI) in passenger railcars. Guided by this research, an alternative methodology for evaluating OVI that ensures an equivalent or greater level of safety than that provided by the current Federal regulations was developed. The alternative methodology moves the evaluation loads to the collision load path and includes three sets of load magnitudes and pass-fail criteria. This methodology also permits a combination of elastic testing and finite element (FE) analysis to be used. This research program applied the alternative methodology to a passenger railcar. Three tests were performed in concert with FE analyses. The first test was a conventional 800,000-pound buff strength test. The results of this test were used to validate an FE model of the car. The FE model was used to estimate the ultimate, or crippling, load of the car. Two destructive crippling tests were then performed. The crippling FE analysis results were compared with the crippling test results and found to describe the general behavior of the tested cars. The FE analysis estimated a crippling load of 1.19 million pounds, and the two test cars had crippling loads of 1.15 and 1.19 million pounds. The results of this program provide a technical basis for the alternative OVI methodology. The load magnitudes in the new methodology have been shown to be reasonable descriptions of the OVI capacity of conventionally designed passenger railcars.
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