Aeroelastic suppression and stability tailoring mechanism of a nonlinear metastructure-integrated supersonic wing

Nonlinear mechanical metastructures have emerged as a promising approach for aeroelastic suppression in advanced aircraft. This study introduces a clearance-type nonlinear metastructure integrated into a supersonic low-aspect-ratio wing to suppress flutter and tailor its stability boundary. The proposed nonlinear resonators employ piecewise stiffness and clearance characteristics, overcoming limitations inherent in conventional nonlinear stiffness designs that require large deformation to activate strong nonlinear effects. Based on an equivalent wing-plate model of low-aspect-ratio wing, the aeroelastic formulation of nonlinear metastructure wing-plate is developed by incorporating supersonic piston theory aerodynamics, along with the concept of affine transformation and an improved global shape function method. The influences of key resonator parameters and spatial distributions on the flutter behavior are systematically examined. A correlation coefficient defined on aeroelastic mode shape vectors is proposed to quantitatively characterize inter-modal coupling. The flutter coupling mechanism between the wing and the metastructure is elucidated, thereby revealing the underlying tailoring mechanism governing the stability boundary. Furthermore, by exploiting structural modal characteristics, a multi-frequency combined nonlinear metastructure design strategy is developed, which enhances the aeroelastic stability boundary of the wing by 29.6% under low-added-mass condition. This work provides a theoretical foundation and a practical design methodology for the application of nonlinear metastructures in aeroelastic suppression of lightweight aerospace structures.