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In this study, we propose a coaxial composite resonator (CCR) structural unit and experimentally demonstrate that a periodic structural plate composed of CCR units effectively suppresses low-frequency vibrations. Each CCR unit comprises a cylindrical resonant element, a steering wheel-shaped elastic connection, and a framework structure. These components collectively generate elastic wave bandgaps through the intrinsic damping properties of the resonant elements. Finite element analysis was employed to investigate the influence of key parameters on the bandgap (BG) characteristics of the CCR structure. The results indicate that the resonator mass is the primary determinant of the BG onset frequency, with larger resonator masses leading to a lower onset frequency. Additionally, the lattice constant was identified as the most sensitive parameter influencing the BG width, such that an increased lattice constant results in an expanded frequency range of the BG. The validity of the finite element models and the predicted BG properties were confirmed through experimental testing. The CCR structure exhibits significant potential for applications in low-frequency vibration and noise control. [ABSTRACT FROM AUTHOR]

This paper describes a common occurrence in daily life where spherical membranes bounce on rigid surfaces. To investigate the bouncing problem of spherical membranes, an energy method based on a visco-hyperelastic theoretical model was utilized. With the application of neo-Hookean and Gent constitutive models for analysis, we explored the detailed dynamic deformation features of the spherical membrane in both compression and rebound processes. Furthermore, we developed a finite element model based on the viscoelastic spherical membrane, and the obtained results were consistent with the theoretical findings. Additionally, we examined the effects of initial velocity, internal pressure, radius-thickness ratio, and relaxation time on the compression process, and compared the theoretical model with previous experimental results. It is believed that this model can predict the deformation of viscoelastic spherical membranes during bouncing on rigid surfaces. [Display omitted] • Viscoelasticity can describe the energy dissipation of bouncing spherical membrane. • Viscoelastic energy dissipation reduces the ball's bouncing height. • Spherical membrane collision is equivalent to biaxial stretching. • Centroid precision can improve calculation accuracy of deformation. [ABSTRACT FROM AUTHOR]

We study the initiation, evolution, and propagation of localized bulging in a pressurized heperelastic tube where the elastic modulus is non-uniform in the radial direction. The primary deformation prior to instability is characterized within the framework of nonlinear elasticity for a general material constitution and a generic modulus gradient. To unravel the influence of modulus gradient on localized bulging, we employ the incompressible Gent model and select three representative modulus gradients, including a linear, an exponential, and a sinusoidal function. In particular, the sinusoidal one is supposed to model an actual artery structure. In addition, two prototypical loading conditions are considered, namely, either the resultant axial force or the axial length can be fixed. Based on an explicit bifurcation condition in terms of the internal pressure and the resultant axial force for localized bulging, an exhaustive theoretical analysis on bulge initiation is carried out and the effect of geometric and material parameters and the modulus gradient on the critical stretch triggering localized bulging is revealed. It turns out that the modulus mismatch, as well as the position of maximum modulus, can dramatically affect the onset of localized bulging. Then we analytically elucidate the influence of modulus gradient on bulge propagation according to Maxwell's equal area rule and conduct a finite element analysis of bulge evolution. To perform post-bifurcation analysis, a robust finite element model for graded Gent material is established in Abaqus by UHYPER subroutine coding. Interestingly, it is found that a sinusoidally distributed modulus has negligible influence on the critical stretch of bulge initiation, the deformation process of bugle growth, and the maximum size of a bulge. The current analysis not only can be used to qualitatively explain why a healthy human artery evolves into a sandwich structure where the intermediate layer is stiffest but also can provide useful insight into localized instabilities such as necking and beading in graded structures. • Localized bulging in an inflated graded tube is investigated in detail within the framework of nonlinear elasticity. • The influence of the modulus gradient and the position of maximum modulus on the initiation and evolution of localized bulge is unraveled. • Mechanical insight into the mechanism behind the biological evolution of human arteries is supplied. • A finite element model for localized bulging in graded cylindrical tubes is supplemented in Abaqus based on UHYPER subroutine coding. [ABSTRACT FROM AUTHOR]

Highlights • Bulging formation can be prevented in a bilayer tube of arbitrary thickness while retaining moderate extensibility. • Several critical parameters for avoiding localized bulging are determined. • The applicability of an explicit bifurcation condition to layered tubes is validated. Abstract This paper studies the bifurcation behavior in an inflated bilayer tube of arbitrary thickness under inflation and uni-axial extension. It is assumed that both layers are composed of the Gent material with each layer having its own J m , where J m is a material parameter in the Gent model that signifies the maximum extensibility. First, we determine several critical parametrical regions where localized bulging disappears for a single-layer tube. Then we investigate localized bulging in an inflated bilayer tube, where one layer (layer I) of the tube cannot bulge whereas the other part (layer II) can. Surprisingly, we find that such a composite tube is still susceptible to localized bulging and localized bulging can be prevented only if the proportion of layer I exceeds a critical value, no matter whether layer I occupies the inner side or the outer side. Even for a very thin bilayer tube, the same feature holds. The cases of fixed axial force and fixed axial stretch are both studied, and the critical geometrical parameters marking the transition between bulging and no bulging are determined. Moreover, we carry out a numerical analysis by use of the finite element method to verify the applicability of an explicit bifurcation condition and the predicted bifurcation behavior. This paper offers a possible way to avoid bulging formation in a cylindrical tube while retaining moderate extensibility. [ABSTRACT FROM AUTHOR]