The paper deals with the application of simplified dynamic models to the problem of a ride comfort in tracked vehicles for high-speed passenger travel. The studies reported are aimed at the adequate simulation of significant degrees of freedom in a railroad car in order that optimum stiffness and damping characteristics of the car and its truck suspension may be found for improved ride quality. The mathematical model used for this purpose are a four-degree-of-freedom vertical model and a 10-degree-of-freedom lateral model. The vertical model is subject to vertical inputs applied simultaneously to both trucks, and the lateral model is subject to lateral and/or rocking (or cross-level) displacements from the rails. Responses to these inputs, which may be deterministic or random, are obtained in acceleration units for various parts of the system. More emphasis is given to the lateral than to the vertical model and also to responses in the car than in other parts of the system. Nonlinear spring characteristics are simulated in two parts of the lateral truck suspension system. Interaction of railbed flexibility is not included. Results of this study show that car bending flexibility and the stiffness and damping characteristics of vertical and lateral transformer mountings play significant roles in the search for optimum stiffness and damping properties of the model. Optimum damping coefficients for the car bolsters due to sinusoidal inputs were significantly changed for certain nonsinusoidal deterministic and random inputs. (Author)

  • Supplemental Notes:
    • Presented at the Shock and Vibration Symposium (40th), Hampton, Virginia. 21-23 October 1969.
  • Corporate Authors:

    National Aeronautics and Space Administration

    Langley Research Center
    Hampton, VA  United States  23681
  • Authors:
    • Sewall, J L
    • PARRISH, R V
    • Durling, B J
  • Publication Date: 1969-10

Media Info

  • Pagination: 21 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00039250
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Files: TRIS
  • Created Date: Nov 24 1973 12:00AM