Figure 2.

(a) Eigenfrequencies of the system in figure 1 versus the gyricity of the spinners; (b) a magnification of the results presented in (a) for 0≤ω≤30 rad s⁻¹; (c) mode shape of the structure in the limit when Ω → ∞ for ω = 3.45 rad s⁻¹.