Non-hermiticity of metamaterial panel subjected to supersonic aerodynamic force and its asymmetric vibration transmittance

The concept of non-Hermitian mechanics introduces new dimensions to metamaterial research, yet current studies have primarily focused on wave manipulation, neglecting the vibration transmittance characteristics of finite-size metamaterials with boundary reflections. This paper explores the asymmetric vibration transmittance characteristics of a simply supported Non-Hermitian Metamaterial Panel (NHMP) with two lossy resonators, under the impact of supersonic aerodynamic forces. By examining the non-Hermiticity of a non-aerodynamically loaded NHMP and a host panel aeroelastic system separately, we demonstrate that the NHMP subjected to supersonic aerodynamic force is a complex non-Hermitian system, exhibiting asymmetric vibration transmittance driven by both the fluid–structure interaction effect and lossy resonators. We theoretically and numerically clarify that an ideal aeroelastic system, such as a host panel aeroelastic system, functions as a non-Hermitian mechanical system due to the fluid–structure interaction effect, with the critical flutter point aligning with the Exceptional Point (EP). The results of this study indicate that at low dynamic pressures, the lossy resonators primarily govern asymmetric vibration transmittance, whereas at high dynamic pressures, the fluid–structure interaction effect becomes the dominant factor. Notably, at the EP, asymmetric vibration transmittance is unaffected by the mass ratio of lossy resonators, which is attributed to the invariance of the operational deflection shapes of the NHMP at the EP. This study offers a novel perspective on panel aeroelastic systems and non-Hermitian metamaterials, advancing the field through its comprehensive analyses.