A corrugated-core sandwich beam with local resonators for low-frequency broadband elastic wave attenuation

This article attempts to enhance the low-frequency vibration suppression performance of corrugated-core sandwich beams. Multiple local resonators are introduced into the corrugated-core sandwich beam to acquire low-frequency bandgaps with broader bandwidth and higher wave attenuation capability. The governing equations for vibration analysis of the local resonator–attached corrugated-core sandwich beam are established based on the spectral element method, which incorporates the locally resonant effect by adding the dynamic stiffness term of one specific resonator to the degree of freedom that it attaches to. The bandgaps of the proposed periodic structure are further derived by imposing the Bloch boundary conditions. After validating the numerical model through finite element simulations as well as experimental investigations, the bandgaps and vibration transmissibility of the corrugated-core sandwich beam are carried out, both with and without attached local resonators. It is found that the vibration reduction capability of the corrugated-core sandwich beam is greatly enhanced, bringing two low-frequency bandgaps with high attenuation factors and wide bandwidths. Meantime, the first bandgap of resonator-free corrugated-core sandwich beam is broadened apparently. An interesting result is that the bandgap with higher frequency is split by a newly generated passband. Furthermore, parametric studies are performed, and it is found that the regulating characteristics of the bandgaps obtained through varying the attachment location of local resonators are similar to those through tuning their inherent parameters.

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On the Effects of Mistuning a Force-Excited System Containing a Quasi-Zero-Stiffness Vibration Isolator

Journal of Vibration and Acoustics ◽

10.1115/1.4029689 ◽

2015 ◽

Vol 137 (4) ◽

Cited By ~ 19

Author(s):

Ali Abolfathi ◽

M. J. Brennan ◽

T. P. Waters ◽

B. Tang

Keyword(s):

Vibration Isolation ◽

Dynamic Stiffness ◽

Low Frequency ◽

Vibration Isolator ◽

Linear Vibration ◽

Vibration Isolators ◽

Zero Dynamic ◽

Low Frequency Vibration ◽

Excited System ◽

Better Than

Nonlinear isolators with high-static-low-dynamic-stiffness have received considerable attention in the recent literature due to their performance benefits compared to linear vibration isolators. A quasi-zero-stiffness (QZS) isolator is a particular case of this type of isolator, which has a zero dynamic stiffness at the static equilibrium position. These types of isolators can be used to achieve very low frequency vibration isolation, but a drawback is that they have purely hardening stiffness behavior. If something occurs to destroy the symmetry of the system, for example, by an additional static load being applied to the isolator during operation, or by the incorrect mass being suspended on the isolator, then the isolator behavior will change dramatically. The question is whether this will be detrimental to the performance of the isolator and this is addressed in this paper. The analysis in this paper shows that although the asymmetry will degrade the performance of the isolator compared to the perfectly tuned case, it will still perform better than the corresponding linear isolator provided that the amplitude of excitation is not too large.

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Tunable Nonlinear Band Gaps in a Sandwich-Like Meta-Plate

10.21203/rs.3.rs-434518/v1 ◽

2021 ◽

Author(s):

Yu Xue ◽

Jinqiang Li ◽

Yu Wang ◽

Fengming Li

Keyword(s):

Band Gap ◽

Vibration Suppression ◽

Wave Attenuation ◽

Structural Parameters ◽

Low Frequency ◽

Dispersion Analysis ◽

Response Analysis ◽

Working Mechanism ◽

Frequency Wave ◽

The Galerkin Method

Abstract This paper aims to explore the actual working mechanism of sandwich-like meta-plates by periodically attaching nonlinear mass-beam-spring (MBS) resonators for low-frequency wave absorption. The nonlinear MBS resonator consists of a mass, a cantilever beam and a spring that can provide negative stiffness in the transverse vibration of the resonator, and its stiffness is tunable by changing the parameters of the spring. Considering the nonlinear stiffness of the resonator, the energy method is applied to obtain the dispersion relation of the sandwich-like meta-plate and the band-gap bounds related to the amplitude of resonator is derived by dispersion analysis. For the finite sized sandwich-like meta-plate with the fully free boundary condition subjected to external excitations, its dynamic equation is also established by the Galerkin method. The frequency response analysis of the meta-plate is carried out by the numerical simulation, whose band-gap range demonstrates good agreement with the theoretical one. Results show that the band-gap range of the present meta-plate is tunable by the design of the structural parameters of the MBS resonator. Furthermore, by analyzing the vibration suppression of the finite sized meta-plate, it can be observed that the nonlinearity of resonators can widen the wave attenuation range of meta-plate.

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Low-frequency multi-mode vibration suppression of a metastructure beam with two-stage high-static-low-dynamic stiffness oscillators

Acta Mechanica ◽

10.1007/s00707-019-02515-7 ◽

2019 ◽

Vol 230 (12) ◽

pp. 4341-4356 ◽

Cited By ~ 1

Author(s):

Qichen Wu ◽

Gangting Huang ◽

Chong Liu ◽

Shilin Xie ◽

Minglong Xu

Keyword(s):

Vibration Suppression ◽

Dynamic Stiffness ◽

Low Frequency ◽

Two Stage ◽

Mode Vibration ◽

Multi Mode

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Enhanced ride comfort using nonlinear seat suspension with high-static-low-dynamic stiffness

Noise & Vibration Worldwide ◽

10.1177/0957456520901356 ◽

2020 ◽

Vol 51 (4-5) ◽

pp. 63-76 ◽

Cited By ~ 1

Author(s):

Chun Cheng ◽

Yan Hu ◽

Ran Ma

Keyword(s):

Ride Comfort ◽

Structural Parameters ◽

Dynamic Stiffness ◽

Damping Ratio ◽

Low Frequency ◽

Coupled Model ◽

Human Model ◽

Vehicle Speed ◽

Seat Suspension ◽

Low Frequency Vibration

To attenuate the low-frequency vibration transmitted to the driver, a nonlinear seat suspension with high-static-low-dynamic stiffness is designed. First, the force and stiffness characteristics are derived. The nonlinear suspension can achieve the quasi-zero stiffness at the static equilibrium position when the structural parameters are properly designed. Then, a car-seat-human coupled model which consists of a quarter car model, a seat suspension, and a 4 degree-of-freedom human model is established to predict the biodynamic response of the driver. Finally, the isolation performance of the high-static-low-dynamic stiffness seat suspension under two typical road excitations is evaluated separately based on the numerical method. The effects of stiffness ratio, damping ratio, and vehicle speed on the ride comfort are investigated. The results showed that the nonlinear seat suspension outperforms the equivalent linear counterpart and can achieve the best ride comfort when the quasi-zero stiffness condition is satisfied.

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Modeling a Mechanical Molecular Spring Isolator with High-Static-Low-Dynamic-Stiffness Properties

Shock and Vibration ◽

10.1155/2020/8853936 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

Zhanyong Li ◽

Qian Chen ◽

Fengshou Gu ◽

Andrew Ball

Keyword(s):

Vibration Isolation ◽

Dynamic Properties ◽

Piecewise Linear ◽

Dynamic Stiffness ◽

Low Frequency ◽

Isolation System ◽

Isolation Technique ◽

Piston Cylinder ◽

Low Frequency Vibration ◽

Stiffness Model

A mechanical molecular spring isolator (MMSI) is proposed for the purpose of isolating the low-frequency vibration of a heavy payload. The MMSI is a passive vibration isolation technique mimicking molecular spring isolator characteristics of high-static-low-dynamic stiffness (HSLDS). An MMSI consists of a piston-cylinder container filled with the liquid and some hydraulic spring accumulators. The piston would support a lump of mass and be subjected to a specific external vibration excitation force. Those accumulators can get intercommunication by the liquid to produce the transformation from high static stiffness to low dynamic stiffness. The stiffness model of the MMSI with several identical accumulators is established based on the hydrostatic law. After that, some parameters that significantly influence the stiffness characteristics are studied. Results show that the stiffness property of this kind of MMSI demonstrates a piecewise linearity of three segments. It applies the averaging method to acquire amplitude-frequency and phase-frequency relationships of the piecewise linear vibration isolation system. An inevitable jump phenomenon may occur when the exciting force reaches the critical value. The vibration isolation performance is evaluated by energy transmissibility. Finally, an experimental prototype was designed to carry out quasi-static and dynamic experiments to verify the stiffness model and the dynamic properties as an HSLDS vibration isolator.

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Low frequency vibration suppression shape filter and high frequency vibration suppression shape filter

Proceedings of the 2005, American Control Conference, 2005. ◽

10.1109/acc.2005.1470745 ◽

2005 ◽

Author(s):

Li Zhou ◽

E.A. Misawa

Keyword(s):

High Frequency ◽

Vibration Suppression ◽

Low Frequency ◽

High Frequency Vibration ◽

Low Frequency Vibration

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Flexural waves in elastically coupled telescopic metabeams

Journal of Vibration and Acoustics ◽

10.1115/1.4050809 ◽

2021 ◽

pp. 1-28

Author(s):

Rajan Prasad ◽

Arnab Banerjee

Keyword(s):

Wave Propagation ◽

Band Gap ◽

Wave Attenuation ◽

Dynamic Stiffness ◽

Equations Of Motion ◽

Low Frequency ◽

Length Ratio ◽

Beam Equation ◽

Flexural Wave ◽

Constitutive Components

Abstract This paper investigates the flexural wave propagation through elastically coupled metabeams. It is assumed that the metabeam is formed by connecting successive beams with each other using distributed elastic springs. The equations of motion of a representative unit of the above mentioned novel structural form is established by dividing it into three constitutive components that are two side beams, modeled employing Euler-Bernoulli beam equation and an elastically coupled articulated distributed spring connection (ECADSC) at middle. ECADSC is modeled as parallel double beams connected by distributed springs. The underlying mechanics of this system in context of elastic wave propagation is unique when compared with the existing state of art in which local resonators, inertial amplifiers etc. are attached to the beam to widen the attenuation bandwidth. The dynamic stiffness matrix is employed in conjunction with Bloch-Floquet theorem to derive the band-structure of the system. It is identified that the coupling coefficient of the distributed spring layer and length ratio between the side beams and the elastic coupling plays the key role in the wave attenuation. It has been perceived that a considerable widening of the attenuation band gap in the low-frequency can be achieved while the elastically distributed springs are weak and distributed in a small stretch. Specifically, 140% normalized band gap can be obtained only by tuning the stiffness and the length ratio without adding any added masses or resonators to the structure.

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