Rational function approximation-based time-domain aeroelastic analysis of composite plates with material uncertainty

This study presents a time-domain aeroelastic flutter analysis framework for laminated composite structures using the Rational Function Approximation (RFA) method. The unsteady aerodynamic forces are obtained in the frequency domain through the Doublet Lattice Method (DLM), which generates aerodynamic influence coefficients (AICs) over a range of reduced frequencies. These frequency-dependent aerodynamic matrices are approximated using Roger's functions to enable an equivalent state-space representation suitable for time-domain analysis. The presented formulation employs aerodynamic lag states that account for unsteady flow characteristics. The structural and aerodynamic governing equations are converted into the time domain by applying the inverse Fourier transformation and then solving them using the state-space approach. The efficiency of the proposed RFA formulation was tested by comparing its performance against that of the DLM method, traditional p–k (P–K) method, and experimental data, where very good agreement was observed for the aeroelastic analysis (flutter speed and flutter frequency). In addition, stochastic aeroelastic investigations were carried out to assess the effect of uncertainties in material properties on the flutter conditions, revealing high sensitivities of the aeroelastic stability to variations in composite properties. The proposed methodology provides a robust and computationally efficient framework for accurate aeroelastic stability prediction of composite structures.