A mathematical model of a vehicle axle suspended from a fixed chassis is set up and studied. The axle has freedom to move vertically and longitudinally and to wind-up, while the wheels have spin freedom, but are assumed to have the same spin velocity at any time, so that only symmetric motions are possible in the model. Braking torque acts between the axle and the wheels and the tyres generate braking forces at the tyre/road interface which depend on wheel load and longitudinal slip. The longitudinal slip is influenced by the way the tyre rolling radius changes with loading, and appropriate relationships are included for both cross-ply and radial-ply tyres. The motions of the model system are obtained by digital simulation, and the model is shown to be capable of representing axle tramping vibrations in their most basic form. Necessary conditions for effective self-excitation are revealed, implying design practices which will avoid problems in respect of axle tramp. The simplicity of the model has advantages in terms of the examination of particular cases, because it requires relatively little vehicle data, it is easy to program, and it needs little computer simulation time. For the covering abstract of the conference see TRIS 451834. (Author/TRRL)

Media Info

  • Features: Figures; References;
  • Pagination: p. 113-120

Subject/Index Terms

Filing Info

  • Accession Number: 00451848
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: May 31 1986 12:00AM