The Influence of Structural Flexibilities on the Straight-running Stability of Motorcycles
- 1 December 1980
- journal article
- research article
- Published by Taylor & Francis in Vehicle System Dynamics
- Vol. 9 (6) , 327-357
- https://doi.org/10.1080/00423118008968629
Abstract
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. The tyre 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 for small 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.Keywords
This publication has 4 references indexed in Scilit:
- A Solution of the Low-Speed Wheel Flutter Instability in MotorcyclesJournal of Mechanical Engineering Science, 1976
- The Influence of Frame Flexibility on the Lateral Stability of MotorcyclesJournal of Mechanical Engineering Science, 1974
- Analysis of the Dynamic Response of a Rolling String-Type Tire Model to Lateral Wheel-Plane VibrationsVehicle System Dynamics, 1972
- The Stability and Control of MotorcyclesJournal of Mechanical Engineering Science, 1971