Nonlinear analysis of the influence of tire inflation pressure on nose landing gear shimmy

In this work we investigate shimmy oscillations in the nose landing gear of a passenger aircraft and study how they depend on changes in the tire inflation pressure. To achieve this, we consider a mathematical model of a landing gear that includes the influence of the tire pressure via different tire properties, such as cornering force and contact patch length. Experimental data obtained from two radial tires is used as a basis for modeling the influence of inflation pressure on tire properties. Bifurcation analysis of the mathematical model was then be performed. It yields stability diagrams in the plane of velocity and vertical force for different values of the tire inflation pressure. Specifically, we present two-parameter bifurcation diagrams for five different inflation pressures. This allows us to conclude that, for the type of tires considered, the landing gear is less susceptible to shimmy oscillations at higher than nominal inflation pressures.