Figure 4. Frequency response curves of the second mode of the system at resonance ,

From

Harmonic Oscillations and Resonances in 3-D Nonlinear Dynamical System

Usama H. Hegazy, Mousa A. ALshawish

International Journal of Partial Differential Equations and Applications. 2016, 4(1), 7-15 doi:10.12691/ijpdea-4-1-2