AIAA Aviation Forum 2024 July 29-August 2, 2024, Las Vegas, NV, USA Estimation of Critical Aeroelastic Damping Using Dynamic Eigen Decomposition and Artificial Damping Taehyoun (John) Kim Department of Mechanical Engineering University of Washington, Bothell, WA, USA Shan Siddiqui ASML, Hillsboro, OR, USA Bruce Jo Department of Mechanical Engineering Tennessee Technological University, Cookeville, TN, USA Aeronautical industry has primarily relied on the p-k method for aeroelastic damping extrapolation. The p-k method can be numerically unstable in regions where modes are close to one another, and repeated iterations of the eigenproblem are required making the approach expensive. In this paper, an entirely new approach for aeroelastic damping estimation is proposed. It uses the Dynamic Eigen Decomposition to find flutter points adjusted by an artificially imposed structural damping. Based on the new aeroelastic equations of motion modified with the artificial structural damping, neutrally stable solutions are found. The amount of the negative structural damping added is interpreted as the true aeroelastic damping at the subcritical point. This analysis is carried out using the Nyquist stability criterion applied to the perturbed system from a nominal stable condition. For demonstration, Goland wing model with six structural modes at Mach=.7 is examined. It is shown that the proposed method can yield aeroelastic damping of critical modes, i.e., lightly damped modes, accurately close to the results of the p-k iterations without causing the mode tracking issue. 1. Introduction Aeronautical engineers have used the p-k method [1] or the Rational Function Approximation (RFA) [2] to obtain aeroelastic damping at subcritical conditions below a flutter point. The p-k method can be numerically unstable in regions where modes are close to one another with respect to the numerical precision employed, and repeated iterations of the eigenproblem are usually required making the approach computationally expensive. In this paper, an entirely new frequency domain approach for aeroelastic damping estimation is proposed. The method leverages the concept of Dynamic Eigenmodes [3] to find flutter points adjusted by an artificially imposed negative structural damping. Based on the aeroelastic equations of motion modified with the artificial negative structural damping, solutions on the V-g plot may be found. This is accomplished using the Multi-Input Multi-Output (MIMO) Nyquist stability criterion [4] applied to the perturbed system from a nominal stable condition. Dynamic Eigenmodes track the parameter