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A wide variety of pathologies, such as store-induced limit-cycle oscillations, have been observed on highperformance aircraft and have been attributed to transient nonlinear aeroelastic effects. Ignoring the nonlinearity of the structure or the aerodynamics will lead to inaccurate prediction of these nonlinear aeroelastic phenomena. The current paper presents the development and representative results of a high-delity multidisciplinary analysis tool that accurately predicts limit-cycle oscillations (LCOs) of an aeroelastic system with combined structural and aerodynamic nonlinearities. Wind-tunnel measurements have been carried out to validate the ndings of the investigation. The current investigation concentrates on the prediction of the critical physical terms that dominate the mechanism of LCO. The aeroelastic computations predict LCO amplitudes and frequencies in very close agreement with the experimental data. The results emphasize the importance of modeling the nonlinearities of both the uid and structure for the accurate prediction of LCO for nonlinear aeroelastic systems. Nomenclature a = nondimensional distance (in terms of b) from midchord to elastic axis b = semichord of wing c h = viscous damping coef cient in plunge motion c ® = viscous damping coef cient in pitch motion I EA = mass moment of inertia about elastic axis k h = structural stiffness coef cient in plunge motion k ® = structural stiffness coef cient in pitch motion m c = mass of cam m t = total mass of system m w = mass of wing r c = nondimensional distance between elastic axis and cam center of rotation r cg = distance between elastic axis and center of mass ¹ h = structural damping coef cient in pitch motion ¹ ® = structural damping coef cient in pitch motion

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