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In this paper, a tunable sandwich beam metamaterial is designed by implementing a hybrid project composed of the piezoelectric shunted array technique and the inertial amplification mechanism. Concerned with the shunted piezoelectric constitutive relation, the kinematic analysis of added mechanism and the transverse motion of base structure, a theoretical model is established to estimate the band gap characteristics of the sandwich beam lined with pyramidal truss cores using the transfer matrix method, whose accuracy is further validated by the finite element simulations. Numerical results show that multiple stop bands are generated at low frequencies owing to the mechanisms of electromechanical resonance, amplifying inertia and mechanical resonance, certainly enhancing the level of vibration suppression. Subsequently, a comprehensive parametric analysis is conducted to investigate the influences of the shunting circuits and attached mechanism on the attenuation diagrams. It is demonstrated that the hybrid sandwich lattice can offer more tunable space to acquire ultra-broad band gaps. Furthermore, based on the design potential, the amplitudes and bandwidths of the attenuation region are maximized by operating an optimization study. Such advanced attenuation performance can be applied for a wide range of engineering applications. [ABSTRACT FROM AUTHOR]

Low-frequency transverse wave propagation plays a significant role in the out-of-plane vibration control. To efficiently attenuate the propagation of transverse waves at low-frequency range, this letter proposed a new type phononic beam by attaching inertial amplification mechanisms on it. The wave propagation of the beam with enhanced effective inertia is analyzed using the transfer matrix method. It is demonstrated that the low-frequency gap within inertial amplification effects can possess much wider bandwidth than using the local resonance method, thus is more suitable for designing applications to suppress transverse wave propagation. [ABSTRACT FROM AUTHOR]

With the purpose of obtaining complete stop bands which allow one isolate both longitudinal and transverse vibrations in functionally graded beams, this paper adopts the inertial amplification mechanisms via attaching them on the base beam whose material properties are described by the power-law function to study the nature of propagation and attenuation characteristics. The dynamic model of the inertial amplification mechanism is developed to capture inertial forces when the coupled axial-bending deformation is present in the base structure. By employing the principle of the virtual work and the Bloch theory, a discrete formulation is presented to exploit the complex band diagram. Numerical analyses show that multiple stop bands whose attenuation performances are comparable to that of resonance gaps can be obtained, demonstrating the efficiency on suppressing wave propagation over a wide frequency band, which is helpful to expand the range of engineering applications with functionally graded materials for vibration and sound reduction. Furthermore, the effects of the geometrical characteristics of attached substructure, power-law index and material damping are investigated. [ABSTRACT FROM AUTHOR]

In order to acquire multiple and wider stop bands in periodic sandwich lattice, this work applies the inertial amplification mechanisms to the composite sandwich beam with pyramidal truss cores and presents a theoretical study on the wave propagation characteristics of the proposed sandwich lattice. An analytical model based on the plane wave expansion method and the Galerkin method is developed to investigate the dispersion relation of transverse waves propagating through the sandwich beam, whose validity is verified by the numerical simulations of spatial decaying performance predicted by the finite element method. Numerical results of complex band structures show that the proposed sandwich beam can obtain multiple stop bands and possess much wider bandwidth. Employing the developed model, the effects of varying attached substructure, the layout of truss members and the material damping on the attenuation performance are discussed to show the flexibility and to obtain thorough understanding of the system. [ABSTRACT FROM AUTHOR]