The stochastic P-bifurcation behavior of bi-stability in a Duffing oscillator
with fractional damping under multiplicative noise excitation is
investigated. Firstly, in order to consider the influence of Duffing term,
the nonlinear stiffness can be equivalent to a linear stiffness which is a
function of the system amplitude, and then, using the principle of minimal
mean square error, the fractional derivative term can be equivalent to a
linear combination of damping and restoring forces, thus, the original
system is simplified to an equivalent integer order Duffing system.
Secondly, the system amplitude?s stationary Probability Density Function
(PDF) is obtained by stochastic averaging, and then according to the
singularity theory, the critical parametric conditions for the system
amplitude?s stochastic P-bifurcation are found. Finally, the types of the
system?s stationary PDF curves of amplitude are qualitatively analyzed by
choosing the corresponding parameters in each area divided by the transition
set curves. The consistency between the analytical results and the numerical
results obtained from Monte Carlo simulation verifies the theoretical
analysis, and the method used in this paper can directly guide the design of
the fractional order controller to adjust the behaviors of the system.