Predicting freeplay-induced aeroelastic limit-cycle oscillations using pre-critical output data
Year: 2026
Type: article
Abstract: This paper introduces an output-based approach for predicting aeroelastic limit-cycle oscillations due to freeplay---a concentrated stiffness nonlinearity that affects actuated structures. The approach uses output data from pre-critical free-response time histories to estimate the system's recovery rate to equilibrium as a function of a response variable and a varying parameter. Building on previous research on global stiffness nonlinearity, a novel formulation is proposed to handle the concentrated nonlinearity of freeplay. This consists of a physics-informed, multi-variable fitting and extrapolation workflow to predict the zero-recovery-rate frontier in the parameter-amplitude plane, informed by recovery rate data estimated using an envelope-free approach. The approach is demonstrated on an idealized tilting propeller in airplane mode, with freeplay in the tilting mechanism. Predictions use simulated time histories from an analytical model, and they are verified against direct time-marching solutions. The proposed approach effectively captures regions of the parameter-amplitude plane where limit-cycle oscillations develop using output data from as few as one pre-critical time history. These results pave the way for future investigation of higher-complexity aeroelastic systems. The proposed approach may also apply to other dynamical systems with freeplay or akin concentrated nonlinearities. While this work focuses on computational applications, the proposed output-based approach is amenable to experimental demonstration.
Source: Journal of Fluids and Structures
Authors: Michael B. Hartin, Cristina Riso
Institution: Georgia Institute of Technology
Language: English
Subfield: Aerospace Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,740
OpenAlex ID: W7172337099