Strange nonchaotic attractors and multistability in a two-degree-of-freedom quasiperiodically forced vibro-impact system

In this work, we initially study the strange nonchaotic dynamics of a two-degree-of-freedom quasiperiodically forced vibro-impact system. It is shown that SNAs occur between two chaotic regions, but not between the quasiperiodic region and the chaotic one. Subsequently, we mainly focus on the abundant multistability in the system, especially the coexistence of SNAs and quasiperiodic attractors. Besides, the coexistence of quasiperiodic attractors of different frequencies, and the coexistence of quasiperiodic attractors and chaotic attractors are also uncovered. The basins of attraction of these coexisting attractors are obtained. The quasiperiodic attractor can transform into a chaotic attractor directly through torus break-up withoutpa ssing through an SNA. The nonchaotic property of strange nonchaotic attractors (SNAs) is verified by its maximal Lyapunov exponent, and the strange property of SNAs is described by its phase sensitivity, power spectrum, fractal structure and rational approximations.