Technical Reports

Evaluation of Semi-Empirical Analyses for Railroad Tank Car Puncture Velocity, Part II: Correlations with Engineering Analyses

  • 01
  • Nov
  • 2001
AUTHOR: D.Y. Jeong, Y.H. Tang, and A.B. Perlman
SUBJECT: Hazardous Materials
ABSTRACT: This report is the second in a series focusing on methods to determine the puncture velocity of railroad tank car shells. In this context, puncture velocity refers to the impact velocity at which a coupler will completely pierce the shell and puncture the tank. In the first report in this series, a set of semi-empirical equations was evaluated by comparing calculated puncture velocities with data from tank car impact tests. These equations were originally developed by the RPI-AAR Tank Car Safety Committee and later modified by the industry to account for head shield protection and jacket insulation. The semi-empirical equations generally produced reasonable and conservative estimates of puncture velocity when compared with the experimental data. However, differences between the calculated and observed results become more widespread when the tank is pressurized or when shield protection is present. Moreover, alternative methods to determine puncture velocity may be observed by the industry to avoid overdesign. In this report, methods to predict puncture velocity based only on engineering mechanics principles (i.e., no empiricism) are developed and described. Results from the semi-empirical approach are compared with results from the engineering methods. These methods rely on both analytical and computational tools to examine the structural behavior of tanks with ellipsoidal shapes. These tools include finite element and dynamic lumped mass models.
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