Estimating Flutter Bifurcation Diagrams Using the State Velocity

Abstract

This paper introduces a method for estimating flutter bifurcation diagrams of systems described by time-domain state-space models. The method estimates the bifurcation diagram by quantifying changes in the recovery rate in the preflutter regime. The recovery rate is approximated from the state velocity, overcoming the need for transient output data in existing methods that use this quantity. Demonstration examples involve an analytical system and a typical section with smooth nonlinearities in the pitch degree of freedom. The proposed method captures the bifurcation type and the amplitude trend of the bifurcation diagram without transient or iterative calculations, and with no assumed knowledge of the postflutter dynamics. These features ease applications that involve flutter bifurcation analyses for many parameter choices and in automated processes, from design space exploration to optimization.