  This study investigates a low degree-of-freedom (DoF) mechanical model of
shimmying wheels. The model is studied using bifurcation theory and numerical
continuation. Self-excited vibrations, that is, stable and unstable periodic
motions of the wheel, are detected with the help of Hopf bifurcation
calculations. These oscillations are then followed over a large parameter range
for different damping values by means of the software package AUTO97. For
certain parameter regions, the branches representing large amplitude stable and
unstable periodic motions become isolated following an isola birth. These
regions are extremely dangerous from an engineering view-point if they are not
identified and avoided at the design stage.
