Eventos Anais de eventos
DINAME 2017
XVII International Symposium on Dynamic Problems of Mechanics
BIFURCATION ANALYSIS OF AIRCRAFT NOSE LANDING GEAR SHIMMY
Submission Author:
Flavio D. Marques , SP , Brazil
Co-Authors:
Gustavo Coraça, Leon Silveira Abramovith, Flavio D. Marques
Presenter: Flavio D. Marques
doi://10.26678/ABCM.DINAME2017.DIN17-0024
Abstract
Shimmy is a self-excited nonlinear oscillation that is observed in aircraft landing gears. This phenomenon is influenced by parameters from the landing gear structural dynamics to the tire properties. Structural and tyre nonlinearities lead to complex dynamics of difficult modeling. Moreover, nonlinear behavior of pre- or post-shimmy is typically related to Hopf bifurcation. The objective of this work is to present a shimmy prediction model that considers both structural flexibility and nonlinear tyre representations to the analysis of the respective nonlinear behavior. The model is representative of an aircraft nose landing gear of one wheel. The structure comprises an axle modeled in torsion with smooth nonlinearities on the stiffness values. For the tire model, the straight tangent tyre model, the Von Schlippe and the rigid ring tyre models are considered, thereby allowing comparisons between various forms of modeling. Hopf bifurcations are identified and diagrams of amplitudes versus wheel speed are used to investigate the conditions in which the system is supercritical or subcritical. The bifurcations are also analysed for parameters range from structure and tyre models.
Keywords
Shimmy, Hopf bifurcation, nonlinear dynamics, self-excited systems, Landing gear.
