Yu-Xin Hao

Traditional thin-walled cylindrical shells tend to induce significant vibrations and noise under dynamic loads, making vibration suppression crucial. This paper proposes a sandwich-structured cylindrical curved panel with inertial amplification (IA) metamaterial characteristics. Its core layer employs a lever-type IA mechanism, sandwiched between two curved face panels. The two face panels and the lever-type IA resonators of the core layer are connected via support rods, with hinge connections serving as the fulcrums of the lever structures. Implementation of the thin shell theory within Hamilton’s principle framework enables the derivation of the sandwich panel’s dynamic governing equations. Subsequently, by means of the plane wave expansion (PWE) method, its bandgap structures and dispersion relations are numerically calculated. Finite element numerical simulations are employed to validate the theoretical results, and a comprehensive investigation of the bandgap characteristics and vibration behaviors is conducted. An in-depth study is further carried out on the effects of various structural parameters, boundary conditions, and other factors on the bandgap structures. Results demonstrate that resonator-induced motion amplification augments the apparent mass of the system. This amplification facilitates the reduction of bandgaps without the need for additional lumped masses or heavy local resonators. Thus, the proposed structure can be utilized in the future to achieve excellent vibration isolation performance for thin cylindrical shell structures.

In order to attenuate the various low-frequency vibrations that may cause structural fatigue and damage, impact human health and affect work efficiency, this paper presents a novel local resonance metamaterial sandwich meta-plate structure containing a cantilever spiral beam-mass resonator, and investigates vibration reduction effects of it within the obtained low-frequency bandgap range. For this purpose, a theoretical model of the low-frequency resonator being composed by a cantilever Archimedean spiral beam and cylindrical mass is established. The natural frequency of it is calculated by solving the Euler-Lagrange equation of the resonator. The accuracy and reliability of the theoretical model are verified through COMSOL simulation. The stress distribution of five types of cantilever spiral beam mass resonators (i.e. Archimedes spiral, triangle spiral, square spiral, pentagon spiral and hexagon spiral) and different cross-sectional shapes (rectangular, square, circular, diamond and triangular) are analyzed. Then, a unit cell model of a sandwich meta-plate with a cantilever Archimedean spiral beam resonator is selected. Hamilton’s principle is used to deduce the bandgap range under infinite periods, and the theoretical solutions are also verified. The parameter optimization of the substrate plate and resonator are also studied. Moreover, the effects of the various structural variables on the bandgap range are systematically explored. Finally, the dynamic responses of the sandwich meta-plate composed of [ ]-unit cells under different excitation frequencies, boundary conditions and structural damping are analyzed.

This paper introduces a comprehensive methodology for the investigation of free vibrations in intelligent composite constructions. The design integrates a functionally graded graphene platelet-reinforced composite (FG-GPLRC) core with magnetoelastic faculae composed of BaTiO ₃ –CoFe ₂ O ₄ . Four GPL distributions within the FG-GPLRC core enhance its performance. Material characterization employs the enhanced Halpin–Tsai method, enabling precise computation of the composite’s properties. Coupling effects across elastic, thermal, electrical, and magnetic fields are elucidated. Nonlinear equations for controlling smart, gradient-thickness FG-GPLRC panels are derived using first-order shear deformation theory (FSDT) and Hamilton’s Principle. Natural frequencies are determined via double triangular series approximation and Galerkin’s method. A detailed parameter analysis investigates the influence of GPL on centration, distribution, temperature, trapezoid angles, base dimensions, and thickness on vibration modes and frequencies. Insights reveal how geometry, materials, and thickness gradients affect smart composite dynamics. The model’s accuracy is verified against finite element simulations, showcasing its utility for analyzing advanced composites under free vibration.