THE INFLUENCE OF STRUCTURAL FLEXIBILITIES ON THE STRAIGHT-RUNNING STABILITY OF MOTORCYCLES

A new tyre model for studies of motorcycle lateral dynamics,and three new motorcycle models, each incorporating a different form of structural compliance, are developed. Thetyre model is based on "taut string" ideas, and includes consideration of tread width and longitudinal tread rubber distortion and tread mass effects, and normal load variation. Parameter values appropriate to a typical motorcycle tyre are employed. The motorcycle models are forsmall lateral perturbations from straight running at constant speed, and include (a) lateral compliance of the front wheel in the front forks, (b) torsional compliance of the front forks, and (C) torsional compliance in the rear frame at the steering head about an axis perpendicular to the steering axis. Results in the form of eigenvalues, indicating modal damping properties and natural frequencies are presented for each model. The properties of four large production machines for a range of forward speeds, and the practicable range of stiffnesses are calculated, and the implications are discussed. It is concluded that typical levels of structural compliance in models (a) and (C) contribute significantly to the steering behaviour properties of large motorcycles, and their observed behaviour can be understood better in terms of the new results than of those existing previously. Some conclusions relating to optimal structural stiffness properties are also drawn. (Author/TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00423114
• Corporate Authors:

  Swets & Zeitlinger

  Heereweg 347B
  2161 CA Lisse,   Netherlands 
• Authors:
  • SHARP, R S
  • ALSTEAD, C J
• Publication Date: 1980-12

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 327-357
• Serial:
  • Vehicle System Dynamics
  • Volume: 9
  • Issue Number: 6
  • Publisher: Taylor & Francis
  • ISSN: 0042-3114
  • EISSN: 1744-5159
  • Serial URL: https://www.tandfonline.com/toc/nvsd20/current

Subject/Index Terms

• TRT Terms: Aerodynamics; Compliance; Dynamics; Frames; Mathematical models; Motorcycles; Natural frequency; Rubber; Speed; Stability (Mechanics); Steering; Stiffness; Tire treads; Tires; Torsion; Vehicle design; Vehicle dynamics
• Uncontrolled Terms: Lateral loads; Side
• ITRD Terms: 5492: Aerodynamics; 5473: Dynamics; 3322: Frame; 6473: Mathematical model; 1221: Motorcycle; 5549: Natural frequency; 9074: Side; 5408: Speed; 5930: Stability; 1834: Steering (process); 5931: Stiffness; 5512: Torsion
• Subject Areas: Design; Highways; Vehicles and Equipment; I91: Vehicle Design and Safety;

Filing Info

• Accession Number: 00334984
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: Sep 16 1981 12:00AM