Approximate Numerical Continuation for Aeroelastic Systems Undergoing Aperiodic Limit Cycle Oscillations

This paper presents a modified numerical continuation approach for predicting the bifurcation
behaviour of aeroelastic systems undergoing aperiodic limit cycles oscillations. Such
oscillations can occur due to a number of nonlinear functions. Here, backlash nonlinearity in
the aileron stiffness for a Generic Transport Aircraft is considered. It is shown that classical
numerical continuation will fail due to the aperiodic nature of the limit cycles and the inability
to perform period scaling and phase fixing. An alternative, approximate numerical continuation
method is proposed, based on longer numerical integration sequences and a heuristic method
for determining the period of the limit cycle oscillations. The approach is applied successfully
to a simulated aeroelastic model of the Generic Transport Aircraft with backlash.