Multi-resonant piezoelectric metamaterials for broadband isolation of elastic wave transmission

2021 ◽  
Author(s):  
Kaijun Yi ◽  
Zhiyuan Liu ◽  
Rui Zhu
Keyword(s):  
Transfer Function ◽  
Elastic Wave ◽  
Digital Circuits ◽  
Bending Stiffness ◽  
Multiple Frequency ◽  
Vibration Mitigation ◽  
Multiple Line ◽  
Plates And Shells ◽  
Isolation Effects ◽  
General Method

Abstract This paper proposes a general method to design multi-resonant piezoelectric metamaterials. Such metamaterials contain periodically distributed piezoelectric patches bonded on the surfaces of a host structure. The patches are assumed to be shunted with digital circuits. A transfer function is designed to realize multi-resonance. The transfer function is derived only using the parameters of the patches. Consequently, it can be used to realize any type of multi-resonant metamaterial structures, like beams, plates and shells. The mechanism of generating multi-bandgaps by the transfer function is explained by analytically studying the effective bending stiffness of a multi-resonant piezo-metamaterial plate. It is shown that the transfer function induces multiple frequency ranges in which the effective bending stiffness becomes negative, consequently results in multiple bandgaps. The characteristics of these bandgaps are investigated, coupling and merging phenomena between them are observed and analyzed. Isolation effects of vibration transmission (elastic wave) in the metamaterials at multiple line frequencies or within a broad frequency band are numerically verified. The proposed multi-resonant piezoelectric metamaterials may open new opportunities in vibration mitigation of transport vehicles and underwater equipment.

Multiple-Frequency Nanoindentation Testing

2004 ◽  
Vol 841 ◽  
Author(s):  
A. C. Fischer-Cripps
Keyword(s):  
Mechanical Properties ◽  
Transfer Function ◽  
Frequency Modulation ◽  
Driving Force ◽  
Multiple Frequency ◽  
Sinusoidal Modulation ◽  
Nanoindentation Testing ◽  
Instrument Response ◽  
Force Signal ◽  
Dynamic Nanoindentation

ABSTRACTThis paper describes a new method of dynamic nanoindentation testing whereby, instead of the imposition of a single sinusoidal modulation onto the driving force signal, a multiple-frequency modulation is applied and a Fourier analysis used to extract frequency-dependent mechanical properties. The instrument response is cancelled by the use of a reference transfer function using an equalization process. The present work gives details of the method and presents some example measurements.

scholarly journals Multi-Frequency Broadband Vibration Mitigation of a Beam Under Tensile Load

2022 ◽  
Author(s):  
Marcela Machado ◽  
Maciej Dutkiewicz
Keyword(s):  
Notch Filter ◽  
Tensile Load ◽  
Mass Ratio ◽  
Multiple Frequency ◽  
Simple Formulation ◽  
Vibration Mitigation ◽  
Vibration Attenuation ◽  
Ideal Number ◽  
Dynamic Absorber ◽  
The Ideal

Abstract The vibration characterization is directly associated with the system’s physical properties, such as mass, damping, and stiffness. For over a century, vibration resonator or dynamic absorber has been used for vibration control and mitigation in many sectors of engineering. A limitation of this device is that it acts as a notch filter, which is only effective over a narrow band of frequencies. Therefore, researchers have designed the call metamaterial, which in this case, targets the improvement of vibration attenuation and induces locally resonant bandgaps. This work investigates the broadband vibration mitigation of a beam under tensile load with periodically attached dynamic absorbers. The study uses the modal analysis approach, a simple formulation that only depends on the resonator target frequency and total mass ratio to investigate single and multiple-frequency bandgap formation. Metamaterial and rainbow metamaterial beam under tensile load are employed to widen the gap. In practical designs, a finite number of resonators is required for the open bandgap, and this ideal number is explored in the paper. Additionally, a tensiled beam (cable) virtual twin is built from a physical system to forecast its broadband vibration mitigation with the metamaterial approach. Numerical investigations are conducted regarding the effects of mass ratio and the ideal mass ratio on the open and on the gap convergence, as well as resonators in single and multiple arrangements inducing multiple gaps.

Effect of Shear in Transverse Impact on Beams

1951 ◽  
Vol 165 (1) ◽  
pp. 176-188 ◽  
Author(s):  
D. G. Christopherson
Keyword(s):  
Elastic Wave ◽  
Shear Stiffness ◽  
Bending Stiffness ◽  
Experimental Results ◽  
Maximum Force ◽  
Transverse Impact ◽  
Wide Range ◽  
The Impact ◽  
Dominant Part ◽  
Good Agreement

In this paper the problem of transverse impact on a uniform beam is considered theoretically. Two examples which can be taken as representing a wide range of impacts which occur in practice are referred to particularly: (1) the beam struck transversely by a uniform square-ended rod travelling perpendicularly to it; (2) the same problem for the striker having a spherical end. In these examples it is shown that the ability of the beam to deflect in shear as well as in bending plays a dominant part in what takes place, and that, as far as the force between striker and beam is concerned, the length of the beam is usually without importance, as there is not time during the impact for an elastic wave to travel to the ends of the beam and return. It is shown that in regard to example (2) the theory presented is in good agreement with Arnold's experimental results obtained some years previously, and curves are given from which the maximum force between beam and striker can be obtained in terms of three parameters, representing respectively the velocity, the mass, and the radius of the striker, each dependent on the ratio of shear stiffness to bending stiffness for the beam.

Feedforward Control of Single-Link Flexible Manipulators by Discrete Model Inversion

1999 ◽  
Vol 121 (4) ◽  
pp. 713-721 ◽  
Author(s):  
V. Feliu ◽  
K. S. Rattan
Keyword(s):  
Transfer Function ◽  
Feedforward Control ◽  
Point Of View ◽  
Model Inversion ◽  
Single Link ◽  
Feedforward Controller ◽  
Tip Position ◽  
Flexible Arms ◽  
System Transfer Function ◽  
General Method

The design of feedforward controllers to control the position of single-link flexible arms is developed in this paper. The objective is to drive the tip position along a commanded trajectory without any oscillations at the tip. The method is based on the well-known dynamics model inversion technique. Since the controllers are implemented on a computer, the dynamic inversion of the single-link flexible arm is studied from a discrete point of view. A general method to obtain a feedforward controller is developed, even in the case when the system transfer function is of nonminimum phase. The method is general in the sense that it removes oscillation in the arm with any number of vibration modes. A method to modify the transfer function of these controllers to improve the robustness is also proposed in this paper. It is shown that the input preshaping scheme developed by Singer and Seering is a special case of this method. The design technique is illustrated with numerical examples and a comparison with the input preshaping method is carried out.

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