scholarly journals Investigation of 2D Rainbow Metamaterials for Broadband Vibration Attenuation

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5225
Author(s):  
Han Meng ◽  
Dimitrios Chronopoulos ◽  
Nick Bailey ◽  
Lei Wang
Keyword(s):  
Vibration Suppression ◽  
Periodic Structures ◽  
Laser Doppler Vibrometer ◽  
Testing System ◽  
Curved Beams ◽  
Attenuation Level ◽  
Vibration Attenuation ◽  
Manufacturing Technologies ◽  
Mechanical Shaker ◽  
2D Space

Phononic crystals (PnCs) and metamaterials are widely investigated for vibration suppression owing to the bandgaps, within which, wave propagation is prohibited or the attenuation level is above requirements. The application of PnCs and metamaterials is, however, limited by the widths of bandgaps. The recently developed rainbow structures consisting of spatially varied profiles have been shown to generate wider bandgaps than periodic structures. Inspired by this design strategy, rainbow metamaterials composed of nonperiodic mass blocks in two-dimensional (2D) space were proposed in the present study. The blocks were connected by curved beams and tessellated with internal voids to adjust their masses. In order to demonstrate the effects of the rainbow design, two 2D metamaterials, with periodic and nonperiodic units, respectively, were investigated and manufactured using additive manufacturing technologies. Receptance functions, i.e., displacement frequency response functions, of the manufactured metamaterials were calculated with finite element models and measured with a testing system containing a mechanical shaker, an impedance head, and a laser Doppler vibrometer. The obtained numerical and experimental results showed that the metamaterial with rainbow blocks has extended bandgaps compared with the periodic metamaterial.

Vibration Measurement and Monitoring of a Rotating Disk Using Contactless Laser Excitation

2013 ◽  
Author(s):  
Itsuro Kajiwara ◽  
Naoki Hosoya
Keyword(s):  
Laser Doppler Vibrometer ◽  
Rotating Disk ◽  
Disk Drive ◽  
Vibration Characteristics ◽  
Vibration Measurement ◽  
Testing System ◽  
Rotating Disks ◽  
Vibration Testing ◽  
Structural Surface ◽  
Theoretical Analyses

This paper proposes a contactless vibration testing system for rotating disks based on an impulse response excited by a laser ablation. High power YAG pulse laser is used in this system for producing an ideal impulse force on structural surface without contact. The contactless vibration testing system is composed of a YAG laser, laser Doppler vibrometer and spectrum analyzer. This system makes it possible to measure vibration characteristics of structures under operation, such as vibration measurement of a rotating disk. The effectiveness of this system is confirmed by experimental and theoretical analyses. In this paper, a platter of hard disk drive is employed as an experimental object. Vibration characteristics of a rotating and non-rotating platter are measured and compared with the results of theoretical analysis.

Piezoelectric Networks for Vibration Suppression of Mistuned Bladed Disks

2007 ◽  
Vol 129 (5) ◽  
pp. 559-566 ◽  
Author(s):  
Hongbiao Yu ◽  
K. W. Wang
Keyword(s):  
Vibration Suppression ◽  
Periodic Structures ◽  
Electric Circuit ◽  
Forced Response ◽  
Bladed Disks ◽  
Vibration Localization ◽  
Network Concept ◽  
Engine Order ◽  
The Individual ◽  
Local Circuits

Extensive investigations have been conducted to study the vibration localization phenomenon and the excessive forced response that can be caused by mistuning in bladed disks. Most previous researches have focused on analyzing∕predicting localization or attacking the mistuning issue via mechanical tailoring. Few have focused on developing effective vibration control methods for such systems. This study extends the piezoelectric network concept, which has been utilized for mode delocalization in periodic structures, to the control of mistuned bladed disks under engine order excitation. A piezoelectric network is synthesized and optimized to effectively suppress vibration in bladed disks. One of the merits of such an approach is that the optimum design is independent of the number of spatial harmonics, or engine orders. Local circuits are first formulated by connecting inductors and resistors with piezoelectric patches on the individual blades. Although these local circuits can function as conventional damped absorber when properly tuned, they do not perform well for bladed disks under all engine order excitations. To address this issue, capacitors are introduced to couple the individual local circuitries. Through such networking, an absorber system that is independent of the engine order can be achieved. Monte Carlo simulation is performed to investigate the effectiveness of the network for a bladed disk with a range of mistuning level of its mechanical properties. The robustness issue of the network in terms of detuning of the electric circuit parameters is also studied. Finally, negative capacitance is introduced and its effect on the performance and robustness of the network is investigated.

scholarly journals Cantilever Beam Metastructure for Active Broadband Vibration Suppression

2020 ◽  
Author(s):  
Ratiba Fatma Ghachi ◽  
Wael Alnahhal ◽  
Osama Abdeljaber
Keyword(s):  
Cantilever Beam ◽  
Natural Frequencies ◽  
Vibration Suppression ◽  
Research Work ◽  
Peak Frequency ◽  
Experimental Frequency ◽  
Transmission Frequency ◽  
Vibration Attenuation ◽  
The Masses ◽  
Zigzag Structure

This paper presents a beam structure of a new metamaterial-inspired dynamic vibration attenuation system. The proposed experimental research presents a designed cantilevered zigzag structure that can have natural frequencies orders of magnitude lower than a simple cantilever of the same scale. The proposed vibration attenuation system relies on the masses places on the zigzag structure thus changing the dynamic response of the system. The zigzag plates are integrated into the host structure namely a cantilever beam with openings, forming what is referred to here as a metastructure. Experimental frequency response function results are shown comparing the response of the structure to depending on the natural frequency of the zigzag structures. Results show that the distributed inserts in the system can split the peak response of the structure into two separate peaks rendering the peak frequency a low transmission frequency. These preliminary results provide a view of the potential of research work on active-controlled structures and nonlinear insert-structure interaction for vibration attenuation.

Adaptive-passive structural vibration attenuation using distributed absorbers

2002 ◽  
Vol 216 (3) ◽  
pp. 223-235 ◽  
Author(s):  
N Jalili ◽  
E Esmailzadeh
Keyword(s):  
Vibration Suppression ◽  
Sufficient Conditions ◽  
Structural Vibration ◽  
Dynamic Vibration Absorber ◽  
Vibration Attenuation ◽  
Adaptive Capability ◽  
On Line ◽  
Lumped Masses ◽  
Necessary And Sufficient ◽  
Tuning Strategy

A distributed dynamic vibration absorber with adaptive capability is presented to improve vibration suppression characteristics of harmonically excited structures. A double-ended cantilever beam carrying intermediate lumped masses forms the absorber subsection. The adaptive capability is achieved through concurrent adjustment of the positions of the moving masses, along the beam, to comply with the desired optimal performance. The necessary and sufficient conditions for the existence of periodic oscillatory behaviour, along with some physical bounds placed on the absorber parameters, form a constrained optimization problem for the optimum tuning strategy. Through numerical simulations it is shown that adaptive tuning is achieved by the variation of tuning mass locations such that the first-mode natural frequency is modulated on-line. The optimally tuned absorber provides considerable vibration suppression improvement over the passive and detuned absorbers.

Optimization of Axial Vibration Attenuation of Periodic Structure With Nonlinear Stiffness Without Addition of Mass

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Diego P. Vasconcellos ◽  
Marcos Silveira
Keyword(s):  
Periodic Structure ◽  
Total Mass ◽  
Periodic Structures ◽  
Original Structure ◽  
Dynamical Response ◽  
Nonlinear Stiffness ◽  
Optimal Position ◽  
Simplified Approach ◽  
Vibration Attenuation ◽  
Linear And Nonlinear

Abstract We explore the vibration attenuation of a periodic structure when one absorber with nonlinear cubic stiffness is included without increasing the total mass. Metastructures, and specifically periodic structures, present interesting characteristics for vibration attenuation that are not found in classical structures. These characteristics have been explored for automotive and aerospace applications, among others, as structures with low mass are paramount for these industries, and keeping low vibration levels in wide frequency range is also desirable. It has been shown that the addition of vibration absorbers in a periodic arrangement can provide vibration attenuation for shock input without increasing the total mass of a structure. In this work, the dynamical response of a metastructure with one nonlinear vibration absorber, with same mass as original structure, optimized for vibration attenuation under harmonic input is compared with a base metastructure without absorbers and a metastructure with linear absorbers via the evaluation of the H2 norm of the frequency response. A simplified approach is used to compare linear and nonlinear stiffness based on deformation energy, by considering linear and nonlinear restoring forces to be equal at mean deformation. The dynamical response of the optimal system is obtained numerically, and an optimization procedure based on sequential quadratic programming (SQP) is proposed to find the optimal position and stiffness coefficients of only one nonlinear absorber, showing that it results in lower level of vibrations than original structure and than structure with linear absorbers, while almost the same level as a structure with all nonlinear absorbers.

scholarly journals Longitudinal wave propagation in a one-dimensional quasi-periodic waveguide

2019 ◽  
Vol 475 (2231) ◽  
pp. 20190392
Author(s):  
Vladislav S. Sorokin
Keyword(s):  
Wave Propagation ◽  
Wave Attenuation ◽  
Periodic Structures ◽  
Low Frequency ◽  
Periodic Waveguide ◽  
One Dimensional ◽  
Vibration Attenuation ◽  
Direct Separation ◽  
Longitudinal Wave Propagation ◽  
Spatial Modulations

The paper deals with the analysis of wave propagation in a general one-dimensional (1D) non-uniform waveguide featuring multiple modulations of parameters with different, arbitrarily related, spatial periods. The considered quasi-periodic waveguide, in particular, can be viewed as a model of pure periodic structures with imperfections. Effects of such imperfections on the waveguide frequency bandgaps are revealed and described by means of the method of varying amplitudes and the method of direct separation of motions. It is shown that imperfections cannot considerably degrade wave attenuation properties of 1D periodic structures, e.g. reduce widths of their frequency bandgaps. Attenuation levels and frequency bandgaps featured by the quasi-periodic waveguide are studied without imposing any restrictions on the periods of the modulations, e.g. for their ratio to be rational. For the waveguide featuring relatively small modulations with periods that are not close to each other, each of the frequency bandgaps, to the leading order of smallness, is controlled only by one of the modulations. It is shown that introducing additional spatial modulations to a pure periodic structure can enhance its wave attenuation properties, e.g. a relatively low-frequency bandgap can be induced providing vibration attenuation in frequency ranges where damping is less effective.

Piezoelectric Networks for Vibration Suppression of Mistuned Bladed Disks

Aerospace ◽  
2006 ◽  
Author(s):  
Hongbao Yu ◽  
K. W. Wang
Keyword(s):  
Vibration Suppression ◽  
Periodic Structures ◽  
Electric Circuit ◽  
Forced Response ◽  
Bladed Disks ◽  
Vibration Localization ◽  
Bladed Disk ◽  
Engine Order ◽  
The Individual ◽  
Local Circuits

Extensive investigations have been conducted to study the vibration localization phenomenon and the excessive forced response that can be caused by mistuning in bladed disks. Most previous researches have focused on attacking the mistuning issue in the bladed disk, such as reducing the sensitivity of the structure to mistuning through mechanical tailoring, or design optimization. Few have focused on developing effective vibration control methods for such systems. This study extends the piezoelectric network concept, which has been utilized for mode delocalization in periodic structures, to the control of mistuned bladed disks under engine order excitation. A piezoelectric network is synthesized and optimized to effectively suppress the excessive vibration in the bladed disk caused by mistuning. One of the merits of such an approach is that the optimum design is independent of the number of spatial harmonics, or engine orders. Local circuits are first formulated by connecting inductors and resistors with piezoelectric patches on the individual blades. While these local circuits can function as conventional damped absorber when properly tuned, they do not perform well for bladed disks under all engine order excitations. To address this issue, capacitors are introduced to couple the individual local circuitries. Through such networking, an absorber system that is independent of the engine order can be achieved. Monte Carlo simulation is performed to investigate the effectiveness of the network for bladed disk with a range of mistuning level of its mechanical properties. The robustness issue of the network in terms of detuning of the electric circuit parameters is also studied. Finally, negative capacitance is introduced and its effect on the robustness of the network is investigated.

Concurrent vibration attenuation and low-power electricity generation in a locally resonant metastructure

2022 ◽  
pp. 1045389X2110725
Author(s):  
Mohid Muneeb Khattak ◽  
Christopher Sugino ◽  
Alper Erturk
Keyword(s):  
Vibrational Energy ◽  
Laser Doppler Vibrometer ◽  
Total Power ◽  
Main Beam ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Vibration Attenuation ◽  
Electrodynamic Shaker ◽  
Electrical Loads ◽  
Power Outputs

We investigate piezoelectric energy harvesting on a locally resonant metamaterial beam for concurrent power generation and bandgap formation. The mechanical resonators (small beam attachments on the main beam structure) have piezoelectric elements which are connected to electrical loads to quantify their electrical output in the locally resonant bandgap neighborhood. Electromechanical model simulations are followed by detailed experiments on a beam setup with nine resonators. The main beam is excited by an electrodynamic shaker from its base over the frequency range of0–150 Hz and the motion at the tip is measured using a laser Doppler vibrometer to extract its transmissibility frequency response. The formation of a locally resonant bandgap is confirmed and a resistor sweep is performed for the energy harvesters to capture the optimal power conditions. Individual power outputs of the harvester resonators are compared in terms of their percentage contribution to the total power output. Numerical and experimental analysis shows that, inside the locally resonant bandgap, most of the vibrational energy (and hence harvested energy) is localized near the excited base of the beam, and the majority of the total harvested power is extracted by the first few resonators.

Experimental Evaluation of Structural Intensity in Two-Dimensional Plate-Type Locally Resonant Elastic Metamaterials

2018 ◽  
Vol 85 (4) ◽  
Author(s):  
H. Al Ba'ba'a ◽  
M. A. Attarzadeh ◽  
M. Nouh
Keyword(s):  
Band Gap ◽  
Power Distribution ◽  
Power Flow ◽  
Vibration Suppression ◽  
Laser Doppler Vibrometer ◽  
Two Dimensional ◽  
Structural Power ◽  
Resonance Effects ◽  
Structural Intensity ◽  
Elastic Metamaterials

Elastic metamaterials utilize locally resonant mechanical elements to onset band gap characteristics that are typically exploited in vibration suppression and isolation applications. The present work employs a comprehensive structural intensity analysis (SIA) to depict the structural power distribution and variations associated with band gap frequency ranges, as well as outside them along both dimensions of a two-dimensional (2D) metamaterial. Following a brief theoretical dispersion analysis, the actual mechanics of a finite metamaterial plate undergoing flexural loading and consisting of a square array of 100 cells is examined experimentally using a fabricated prototype. Scanning laser Doppler vibrometer (SLDV) tests are carried out to experimentally measure the deformations of the metamaterial in response to base excitations within a broad frequency range. In addition to confirming the attenuation and blocked propagation of elastic waves throughout the elastic medium via graphical visualizations of power flow maps, the SIA reveals interesting observations, which give additional insights into energy flow and transmission in elastic metamaterials as a result of the local resonance effects. A drastic reduction in power flow magnitudes to the bulk regions of the plate within a band gap is noticeably met with a large amplification of structural intensity around and in the neighborhood of the excitation source as a compensatory effect. Finally, the theoretical and experimentally measured streamlines of power flow are presented as an alternative tool to predict the structural power patterns and track vortices as well as confined regions of energy concentrations.

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