Application of Antiresonance Theory to Helicopters

Bartlett, F. D.; Flannelly, William G.

doi:10.4050/jahs.19.11

Cited by 5 publications

(2 citation statements)

References 3 publications

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“…AA is particularly popular in the design of helicopters too, to absorb the rotor induced vibrations at a fixed frequency. In [88] the application of the antiresonance theory for engineering applications in helicopters is discussed placing either passive, semi-active or active TMDs at collocated or noncollocated locations. In [89] the AA in helicopters is studied in order to absorb the rotor induced vibrations.…”

Section: Antiresonance Assignment In Helicoptersmentioning

confidence: 99%

Beyond the Tuned Mass Damper: a Comparative Study of Passive Approaches to Vibration Absorption Through Antiresonance Assignment

Richiedei

Tamellin

Trevisani

2021

Arch Computat Methods Eng

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Vibration absorption is a core research area in the design and control of structures and machines, and exploiting antiresonances is an effective approach for systems under harmonic excitation. This paper proposes a comparative study and a review of the main passive techniques to antiresonance assignment proposed in the recent literature, by discussing them through some numerical examples too. The techniques discussed include the well-known Tuned Mass Damper, which has been widely developed in the literature. However, as the title reveals, great attention is paid to the methods inherited from the field of dynamic structural modification that assign antiresonances without modifying the number of degrees of freedom, by exploiting a proper modification of the system inertial and stiffness parameters. Due to higher mathematical complexity, these approaches have been less investigated in the literature although they are an effective and less invasive approach to antiresonance assignment, especially for machines. To puzzle out the complicated subject matter of antiresonances, their background and their key features are also discussed by reviewing the main theoretical results and their relationship with the assignment techniques. The paper is also enriched with several numerical examples to compare different methods and investigate the features of antiresonances. The concluding remarks of the paper bring together some open issues in this field of research and outlines some possible research directions.

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Section: Antiresonance Assignment In Helicoptersmentioning

confidence: 99%

Beyond the Tuned Mass Damper: a Comparative Study of Passive Approaches to Vibration Absorption Through Antiresonance Assignment

Richiedei

Tamellin

Trevisani

2021

Arch Computat Methods Eng

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“…As for the negative peaks in vibration transmission curves, it is caused by the anti-resonance of the finite structure. Antiresonance refers to the phenomenon that the displacement of a part of the system is significantly small under some specific frequencies excitation, which is an opposite vibration case to the resonance [32].…”

Section: Analytical Modelmentioning

confidence: 99%

Bandgap and wave propagation of spring–mass–truss elastic metamaterial with a scissor-like structure

Li¹,

Li²,

Xiang³

et al. 2021

J. Phys. D: Appl. Phys.

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Inspired by the inertial amplification mechanism and bandgap characteristic of periodic structures, a type of scissor-like elastic metamaterial is studied for low-frequency vibration attenuation in this paper. Firstly, the 1DOF (degree of freedom) scissor-like chain consisting of masses, trusses, and springs is investigated. The formation of inertial amplification is illustrated, that is, input horizontal movements are converted into larger vertical movements of vertex masses by a scissor-like structure. The resonance and anti-resonance phenomena in transmission curves are explained. Especially, the optimal configuration for low-frequency attenuation is obtained by analytical expressions of the dispersion relation. Then, a 2DOF spring–mass–truss chain is considered to open a bandgap below the vibration attenuation range of the 1DOF chain. The relative movement of masses at different frequencies is explored to understand the bandgap generation. The influence of parameters including the mass ratio, tensile stiffness ratio, shear stiffness ratio, and angle on bandgap boundaries is discussed. Finally, the spatial propagation of a wavelet packet is presented to illustrate the efficiency of the proposed structure in terms of minimizing a broadband excitation transmission. The transmitted component of a wavelet packet through three units of the proposed structure is only 3.8%, which is 22.8% of that through the classic 1D local resonance metamaterial.

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A review of the mechanical inerter: historical context, physical realisations and nonlinear applications

Wagg

2021

Nonlinear Dyn

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In this paper, a review of the nonlinear aspects of the mechanical inerter will be presented. The historical context goes back to the development of isolators and absorbers in the first half of the twentieth century. Both mechanical and fluid-based nonlinear inerter devices were developed in the mid- and late twentieth century. However, interest in the inerter really accelerated in the early 2000s following the work of Smith [87], who coined the term ‘inerter’ in the context of a force–current analogy between electrical and mechanical networks. Following the historical context, both fluid and mechanical inerter devices will be reviewed. Then, the application of nonlinear inerter-based isolators and absorbers is discussed. These include different types of nonlinear energy sinks, nonlinear inerter isolators and geometrically nonlinear inerter devices, many relying on concepts such as quasi-zero-stiffness springs. Finally, rocking structures with inerters attached are considered, before conclusions and some future directions for research are presented.

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Application of Antiresonance Theory to Helicopters

Cited by 5 publications

References 3 publications

Beyond the Tuned Mass Damper: a Comparative Study of Passive Approaches to Vibration Absorption Through Antiresonance Assignment

Beyond the Tuned Mass Damper: a Comparative Study of Passive Approaches to Vibration Absorption Through Antiresonance Assignment

Bandgap and wave propagation of spring–mass–truss elastic metamaterial with a scissor-like structure

A review of the mechanical inerter: historical context, physical realisations and nonlinear applications

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