Technical Reports

Mathematical Modeling of DODX Railcars

  • 01
  • Feb
  • 1980
AUTHOR: C. T. Jones
OFFICE: RPD
REPORT NUMBER: FRA/ORD-78/47
SUBJECT: Evaluation
KEYWORDS: Computer Simulation, DODX Flat Cars, Roll Stability, Wheel Lift, Derailment Tendency
ABSTRACT: This report presents the results of a project conducted to determine the roll stability characteristics of large capacity freight cars, 100 to 200 ton, loaded with high center of gravity containers. The model, obtained from AAR, is a 22 degree-of-freedom, non-linear, time domain model of railcars equipped with two axle trucks. The model was modified to include hydraulic dampers, an improved Coulomb friction damping model, and a track input to simulate perturbed track specified in AAR specification D-65. Also a lower order integration technique and a larger integration stepsize were employed to reduce computer run time. The model was validated against each of four vehicles on which full scale field tests had been conducted. In three of the four cases sufficient agreement was found between the results of the model and those of the field test to proceed with further simulations of other load/suspension configurations. Results of these simulations suggest that improvement in roll stability can be achieved by reducing the vehicle suspension spring rate or similarly increasing the load. It was also found that one of the vehicles studied possessed a dead band in the stroke of the hydraulic stabilizer. By modifying this stabilizer to operate over the full stroke, vehicle dynamic performance should show improvement.
Pdf Download PDF Document [105.7 MB]
No Preview Available

####