Nonlinear supersonic flutter of multibay cross-stream shallow shells

This work investigates the interaction between adjacent bays and the effect of the curvature ratio in the nonlinear response of cross-stream curved panels. The study presents a numerical investigation of shallow shells' linear and nonlinear dynamic behavior exposed to supersonic flutter. The finite element model embedding the aerodynamic piston theory and the Newmark method for direct time-domain integration of the nonlinear aeroelastic equations are used. Results show that the downwind bay of a two-bay cross-stream curved panel oscillates with much higher amplitudes than the equivalent single panel approach for all curvature ratios under consideration. Jump discontinuities in the LCO amplitudes were observed for a range of post-flutter dynamic pressure. The mutual existence of LCO branches in the amplitude envelope was checked through the sensitivity to initial conditions. No sudden jump in the LCO amplitudes was found for the higher curvatures, whereas a more complex behavior is encountered, especially for the downwind bay. Amplitude envelopes show that the nonlinear coupling between adjacent bays severely influences the dynamic behavior of curved panels subjected to cross-stream supersonic flow. Consequently, relying on single panel modeling may be unsafe for structural design and fatigue-life prediction for supersonic panel flutter suppression.