Summary
In this paper, we experimentally observe, for the first time, the coexistence of two phononic frequency comb (PFC) branches emerging in the excitation-frequency sweeps. The experiments were conducted on an electrostatically actuated curved microbeam exhibiting a 1:2 internal resonance. Through the examination of the time history, spectra, phase portraits, and Poincaré sections of these results, we unravel that these two branches originate at different secondary Hopf bifurcation points and terminate in a chaotic attractor.
