Most probable escape paths in periodically driven nonlinear oscillators

The dynamics of mechanical systems, such as turbomachinery with multiple blades, are often modeled by arrays of periodically driven coupled nonlinear oscillators. It is known that such systems may have multiple stable vibrational modes, and transitions between them may occur under the influence of random factors. A methodology for finding most probable escape paths and estimating the transition rates in the small noise limit is developed and applied to a collection of arrays of coupled monostable oscillators with cubic nonlinearity, small damping, and harmonic external forcing. The methodology is built upon the action plot method [Beri et al., Phys. Rev. E 72, 036131 (2005)] and relies on the large deviation theory, the optimal control theory, and the Floquet theory. The action plot method is promoted to non-autonomous high-dimensional systems, and a method for solving the arising optimization problem with a discontinuous objective function restricted to a certain manifold is proposed. The most probable escape paths between stable vibrational modes in arrays of up to five oscillators and the corresponding quasipotential barriers are computed and visualized. The dependence of the quasipotential barrier on the parameters of the system is discussed. Published under an exclusive license by AIP Publishing.

Automated summary

This study develops a methodology for finding the most probable escape paths and estimating transition rates in arrays of coupled nonlinear oscillators under small noise limit. It applies the action plot method, large deviation theory, optimal control theory, and Floquet theory to compute and visualize the escape paths between stable vibrational modes in arrays of up to five oscillators. The study also discusses the dependence of the quasipotential barrier on system parameters.