Bifurcation Analysis of Nose-Landing-Gear Shimmy with Lateral and Longitudinal Bending

摘要

This work develops and studies a model of an aircraft nose landing gear with torsional, lateral, and longitudinalndegrees of freedom. The corresponding three modes are coupled in a nonlinear fashion via the geometry of thenlanding gear in the presence of a nonzero rake angle, aswell as via the nonlinear tire forces. Their interplaymay leadnto different types of shimmy oscillations as a function of the forward velocity and the vertical force on the landingngear.Methods from nonlinear dynamics, especially numerical continuation of equilibria and periodic solutions, arenused to asses how the three modes contribute to different types of shimmy dynamics. In conclusion, the longitudinalnmode does not actively participate in the nose-landing-gear dynamics over the entire range of forward velocity andnvertical force.