The rocking response of railroad freight cars to track cross-level variations is studied using: (1) a reduced complexity digital simulation model, and (2) a quasi-linear describing function analysis. The reduced complexity digital simulation model employs a rail truck model that neglects the high-frequency dynamics of the bolster and wheelset masses, yet includes kinematic center plate, side bearings, and wheelset nonlinear effects. This model has computation-time requirements that are less than one eighth those of more detailed computer simulation models and agrees within 15% percent for the prediction of roll angle, side bearing force, center plate force and wheel force at maximum roll angle response with the more detailed models. A study of quasi-linear describing function techniques to compute the steady-state response of freight cars to equivalent sinusoidal cross-level track variations has demonstrated the feasibility of the technique for the types of nonlinearities important in car response. This technique, which computes steady-state response from a set of nonlinear algebraic equations rather than by numerical integration, is effective for parametric studies in which a series of the responses is required as a parameter is varied incrementally since once the solution is obtained for one set of parameter values, additional responses for an incremental change in the parameter are obtained efficiently.

Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; Photos; Tables;
  • Pagination: 86 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00144091
  • Record Type: Publication
  • Source Agency: Federal Railroad Administration
  • Report/Paper Numbers: FRA-OR&D-76-293 Final Rpt.
  • Contract Numbers: DOT-TS-11201
  • Files: NTIS, TRIS, USDOT
  • Created Date: Jan 16 1977 12:00AM