Maximal Lyapunov Exponents and Steady-State Moments of a VI System based Upon TDFC and VED

This paper focuses on the investigation of a vibro-impact (VI) system based upon time-delayed feedback control (TDFC) and visco-elastic damping (VED) under bounded random excitations. A pretreatment for the TDFC and VED is necessary. A further simplification for the system is achieved by introducing the mirror image transformation. The averaging approach is adopted to analyze the above system relying on a parametric principal resonance consideration. By means of the first kind of a modified Bessel function, explicit asymptotic formulas for the maximal Lyapunov exponent (MLE) are given to examine the almost sure stability or instability of the trivial steady-state amplitude solution. Besides, the steady-state moments (SSM) of the nontrivial solutions of the system's amplitude are derived by the application of the moment method and Itô's calculus. Finally, the stability and its critical situations of the trivial solution are explored in detail through the important system parameters, i.e. embodying the TDFC parameters, the VED parameters, the restitution coefficient, the excitation amplitude and the random noise intensity. They are tested by numerical simulations. Additionally, the exploration of the steady-state moments involves the emergence of the general frequency response curve and the frequency island, discussions of conditions satisfied by the unstable boundary, and variations of the time-delayed island. Stochastic jumps and bifurcations are observed for the stationary joint transition probability density of the system's trivial and nontrivial solutions based on parameter schemes of VED and TDFC.