Broadband Frequency Spectrum Research Articles

Analysis of Field Trial Results for Excavation-Activities Monitoring with φ-OTDR.

Underground telecommunication cables are highly susceptible to damage from excavation activities. Preventing accidental damage to underground telecommunication cables is critical and necessary. In this study, we present field trial results of monitoring excavation activities near underground fiber cables using an intensity-based phase-sensitive optical time-domain reflectometer (φ-OTDR). The reasons for choosing intensity-based φ-OTDR for excavation monitoring are presented and analyzed. The vibration signals generated by four typical individual excavation events, i.e., cutting, hammering, digging, and tamping at five different field trial sites, as well as five different mixed events in the fifth field trial site were investigated. The findings indicate that various types of events can generate vibration signals with different features. Typically, fundamental peak frequencies of cutting, hammering and tamping events ranged from 30 to 40 Hz, 11 to 15 Hz, and 30 to 40 Hz, respectively. Digging events, on the other hand, presented a broadband frequency spectrum without a distinct peak frequency. Moreover, due to differences in environmental conditions, even identical excavation events conducted with the same machine may also generate vibration signals with different characteristics. The diverse field trial results presented offer valuable insights for both research and the practical implementation of excavation monitoring techniques for underground cables.

Penning-trap eigenfrequency measurements with optical radiofrequency detectors

We use an electric-dipole laser-driven transition to precisely measure the cyclotron-frequency ratios of the pairs Ca+42−Ca+40, Ca+44−Ca+40, and Ca+48−Ca+40 in a 7-tesla Penning trap. A single laser-cooled (T≈1 mK) ion serves, together with photon-counting and photon-imaging units, as a radiofrequency detector covering a broadband frequency spectrum, in the present case from kHz to a few MHz. Such detectors (Ca+40,42,44,48) allow measuring extremely small forces increasing the sensitivity in Penning-trap mass spectrometry. The direct determination of the ions' amplitudes makes a cyclotron-frequency measurement process more robust against inhomogeneities of the magnetic field and/or deviations of the electric quadrupole field due to mechanical imperfections of the trap. Published by the American Physical Society 2024

Gyrokinetic turbulence modeling of a high performance scenario in JT-60SA

Local gyrokinetic simulations are used to model turbulent transport for the first time in a representative high-performance plasma discharge projected for the new JT-60SA tokamak. The discharge features a double-null separatrix, 41 MW of combined neutral beam heating and electron cyclotron heating, and a high predicted ratio of the normalized plasma kinetic to magnetic pressure β. When considering input parameters computed from reduced transport models, gyrokinetic simulations predict a turbulent heat flux well below the injected 41 MW. Increasing the background gradients, on the other hand, can trigger a non-zonal transition (NZT), causing heat fluxes to no longer saturate. Furthermore, when considering fast ions in the simulations, a high-frequency mode is destabilized that substantially impacts the turbulence. The NZT is avoided by reducing the electron pressure by 10% below its nominal value, and the fast-ion resonance is removed by reducing the fast-ion temperature. The thus-obtained simulation features broadband frequency spectra and density and temperature fluctuation levels δn/n≈1% –2%, δT/T≈1% –6% that should be measurable with fluctuation diagnostics planned for JT-60SA. The temperature profile is fixed by the critical main-ion temperature gradient as a consequence of the high stiffness; heat fluxes increase by a factor of ten when increasing the main ion temperature gradient by 17%. Despite large gradients, it is demonstrated that, due to the large β, retaining compressional magnetic field fluctuations and in particular, the contribution of the pressure gradient in the ∇B drifts, is crucial to achieving non-zero heat fluxes.

A Mechanism for Large-Amplitude Parallel Electrostatic Waves Observed at the Magnetopause

Large-amplitude electrostatic waves propagating parallel to the background magnetic field have been observed at the Earth’s magnetopause by the Magnetospheric Multiscale (MMS) spacecraft. These waves are observed in the region where there is an intermixing of magnetosheath and magnetospheric plasmas. The plasma in the intermixing region is modeled as a five-component plasma consisting of three types of electrons, namely, two counterstreaming hot electron beams and cold electrons, and two types of ions, namely, cold background protons and a hot proton beam. Sagdeev pseudo-potential technique is used to study the parallel propagating nonlinear electrostatic solitary structures. The model predicts four types of modes, namely, slow ion-acoustic mode, fast ion-acoustic mode, slow electron-acoustic mode and fast electron-acoustic modes. Except the fast ion-acoustic mode, all other modes support solitons. Whereas slow ion-acoustic solitons have positive potentials, both slow and fast electron-acoustic solitons have negative potentials. For the case of 4% cold electron density, the slow ion-acoustic solitons have electric field ∼(40–120) mV m−1. The fast Fourier transforms (FFT) of slow ion-acoustic solitons produce broadband frequency spectra having peaks between ∼100 Hz to 1000 Hz. These theoretical predictions are in good agreement with the observations. The slow and fast electron-acoustic solitons could be relevant in explaining the low-intensity high (>1 kHz) frequency waves which are also observed at the same time.

Deep learning-based denoising of acoustic images generated with point contact method

Abstract The versatile nature of ultrasound imaging finds applications in various fields. A point contact excitation and detection method is generally used for visualizing the acoustic waves in Lead Zirconate Titanate (PZT) ceramics. Such an excitation method with a delta pulse generates a broadband frequency spectrum and wide directional wave vector. The presence of noise in the ultrasonic signals severely degrades the resolution and image quality. Deep learning-based signal and image denoising has been demonstrated recently. This paper bench-marked and compared several state-of-the-art deep learning image denoising methods with the classical denoising methods. The best-performing deep learning models are observed to be performing at par or, in some cases, even better than the classical methods on ultrasonic images. We further demonstrate the effectiveness and versatility of the deep learning-based denoising model for the unexplored domain of ultrasound/ultrasonic data. We conclude with a discussion on selecting the best method for denoising ultrasonic images. The impact of this work may help ultrasound-based defects identification equipment manufacturers to adopt a deep learning-based denoising model for more wider and versatile use.

The metrological structural resolution for dimensional x-ray CT: analysis of the comparability between the CEB and the PBS method

The metrological structural resolution (MSR) describes the size of the smallest surface feature that can be measured dimensionally with a given accuracy. Several methods to determine the MSR for dimensional x-ray CT (dXCT) have been proposed in the past, two of which are compared and related in this publication, i.e. the curved-edge based (CEB) and the profile-based spectral (PBS) method. Both methods consider the surface structure as being described by a single surface on the relevant local scale and are also suitable for the application to optical or tactile coordinate measurement systems (CMSs). The CEB method evaluates the radii of circular shapes to determine the width of the Gaussian filter that describes the filtering of the surface by the CMS. The PBS method evaluates the instrument transfer function (ITF) determined by means of the measurement of a surface profile with a broad-band spatial frequency spectrum with a finite cut-off frequency. The PBS method yields the threshold wavelength for which the amplitude of the ITF drops below a certain level. While the resulting quantities of the two methods are very different they evaluate the same characteristic of the CMS. In this publication an analytical relation between those results is derived and shown to exist which is used to define the MSR. Simulated CT scans as well as dXCT measurements are performed to verify this relation. The results for the MSR obtained from both methods are consistent and deviations to the expectations based on theory are within a reasonable range.

Intense multicycle THz pulse generation from laser-produced nanoplasmas

We present a novel scheme to obtain robust, narrowband, and tunable THz emission using a nano-dimensional overdense plasma target, irradiated by two counter-propagating detuned laser pulses. So far, no narrowband THz sources with a field strength of GV/m-level have been reported from laser-solid interaction (mostly half-or single-cycle THz pulses with only broadband frequency spectrum). From two- and three-dimensional particle-in-cell simulations, we find that the strong plasma current generated by the beat ponderomotive force in the colliding region, produces beat-frequency radiation in the THz range. Here we report intense THz pulses (fsimeq 30 ;THz) with an unprecedentedly high peak field strength of 11.9 GV/m and spectral width (Delta f/fsimeq 5.3%), which leads to a regime of an extremely bright narrowband THz source of TW/cm^{2}, suitable for various ambitious applications.

Reinforcement Learning approach of switching bi-stable oscillators to adapt bandgaps of 1D-meta-structures

Meta-structures with dynamic vibrational resonators (DVRs) are programmed to control the propagation of waves and attenuate vibrations over a broadband frequency spectrum. Attributes of DVRs, such as their resonant frequency and mass, determine the location and width of the bandgap, respectively. As a result, to adaptively program bandgaps, one has to modify or tune the eigenvalues of individual DVRs, and a popular approach is to vary the stiffness of each resonator. However, the tunable range of bandgaps is often restricted to maximum change in DVRs’ stiffness. This work presents a novel approach to adaptively program bandgaps of a 1D flexural meta-structure over a broad frequency bandwidth. DVRs with two stable configurations are attached to a beam in developing the meta-structure. A numerical model is developed to illustrate the scope of the novel approach. An experimental investigation then validates the simulated results and shows the extent of the vibration absorption capabilities of the meta-structure. A reinforced learning approach is used to adaptively tune the bandgap over 220 Hz to 840 Hz.

Force and stability mechanism analysis of two types of nonlinear mono-stable and multi-stable piezoelectric energy harvesters using cantilever structure and magnetic interaction

Nonlinear mono-stable and multi-stable piezoelectric energy harvesters have attracted a lot of attention owing to their broadband frequency spectra and excellent energy harvesting performance. Herein, two types of nonlinear mono-stable, bi-stable, tri-stable, and quad-stable piezoelectric energy harvesters using cantilever structure and magnetic interaction are compared and analyzed. Based on the magnetizing current method, the magnetic force equations are obtained. Calculation results demonstrate that the stability of these harvesters is dependent on the equivalent linear elastic force and the vertical magnetic force. The equilibrium point occurs when the equivalent linear elastic force equals to the vertical magnetic force. The relationship between the number of stable equilibrium points E S and the number of the intersections of the two force curves N I is that E S= (N I + 1)/2. Experiments are carried out to verify the equivalent linear elastic force, vertical magnetic force, and the number of stable equilibrium points of the fabricated prototypes. The experimental results are consistent with the calculated results, which verifies the correctness of the stability mechanism. Moreover, it is found that the stability mechanism is also applicable to the harvesters with more stable equilibrium points, such as penta-stable and hexa-stable harvesters. This work reveals the stability mechanism of nonlinear mono-stable and multi-stable energy harvesters using cantilever structure and magnetic interaction, and provides technical methods for the design of multi-stable energy harvesters.

Experimental investigation of characteristics of instability evolution in a centrifugal compressor

The stable range of operation for the centrifugal compressor significantly influences the dynamic, economic, and environment-friendly characteristics of power systems. A deep understanding of the characteristics of instability evolution is necessary to improve the compressor stability. A centrifugal compressor equipped with a vaneless diffuser is experimentally investigated using high-response static-pressure measurements. The results obtained indicate that three typical rotational-speed ranges exist based on the different instability evolution characteristics, which reveals the various impeller–diffuser matching behaviors over the entire speed range. At low-speed ranges ((40%–75%)Nmax, Nmax is the maximum rotational speed), the compressor exhibits stable, Rotating Instability (RI), impeller stall (diffuser stall), and surge modes. The impeller stall mode is induced by RI and propagates downstream, resulting in the diffuser stall and compressor surge modes. In the medium-speed range ((75%–85%)Nmax), the compressor exhibits stable, diffuser stall, RI, and surge modes. In the high-speed range ((85%–100%)Nmax), the compressor exhibits stable, diffuser stall, and surge modes. The dominant instability position is shifted from the impeller to the diffuser as the rotational speed increases. Both the impeller and diffuser stall present an irregular sawtooth static-pressure wave and exhibit broadband frequency spectrum patterns.

Energy Harvesting Performance of a Novel Nonlinear Quad-Stable Piezoelectric Energy Harvester with Only One External Magnet

Nonlinear multi-stable piezoelectric energy harvesters show broadband frequency spectra and excellent energy harvesting performance, owing to their high output power related to inter-well transitions. However, existing quad-stable piezoelectric energy harvesters contain too many structural parameters, which makes the systems clumsy, and increases the difficulties of dynamic analysis and structural optimization. Herein, a nonlinear quad-stable piezoelectric energy harvester, with only one external magnet, is proposed based on the magnetic force characteristics between a ring magnet and a rectangular magnet. Under selected structural parameters, as the magnet spacing increases, the stability characteristic of the harvester changes from quad-stability to bi-stability, and then to mono-stability. The transformation of the stability characteristic results from the changes in the variation rate of the vertical magnetic force. Subsequently, under the filtered Gaussian white noise within the frequency range of 0–120 Hz, the energy harvesting performance of the harvester is simulated by the classic fourth-order Runge-Kutta method. Simulation results show that the performance of the harvester under the quad-stable structural parameters is better than that under the bi-stable structural parameters, independent of whether the excitation acceleration is small or large. This result is related to the potential well characteristics under the quad-stable and bi-stable structural parameters. More specifically, the potential well depths under the quad-stable and bi-stable structural parameters are almost the same, but the distance between the two outer potential wells under the quad-stable structural parameters is larger than that under the bi-stable structural parameters. Finally, a fabricated prototype is used to measure the experimental performance of the harvester. The experimental data and the estimated data share the same trend. This study provides a new conception and technical method for the design, optimization, and application of quad-stable piezoelectric energy harvesters.

Ultrasonic image denoising using machine learning in point contact excitation and detection method

A point contact/Coulomb coupling technique is generally used for visualizing the ultrasonic waves in Lead Zirconate Titanate (PZT) ceramics. The point contact and delta pulse excitation produce a broadband frequency spectrum and wide directional wave vector. In ultrasonic, the signal is corrupted with several types of noises such as speckle, Gaussian, Poisson, and salt and pepper noise. Consequently, the resolution and quality of the images are degraded. The reliability of the health assessment of any civil or mechanical structures highly depends on the ultrasonic signals acquired from the sensors. Recently, deep learning (DL) has been implemented for the reduction of noises from the signals and in images. Here, we have implemented deep learning-based convolutional autoencoders for suitable noise modeling and subsequently denoising the ultrasonic images. Two different metrics, PSNR and SSIM are calculated for quantitative analysis of ultrasonic images. PSNR provides higher visual interpretation, whereas the SSIM can be used to measure much finer similarities. Based upon these parameters speckle-noise demonstrated better than other noise models.

Flat-optics generation of broadband photon pairs with tunable polarization entanglement.

The concept of "flat optics" is quickly conquering different fields of photonics, but its implementation in quantum optics is still in its infancy. In particular, polarization entanglement, strongly required in quantum photonics, is so far not realized on "flat" platforms. Meanwhile, relaxed phase matching of "flat" nonlinear optical sources enables enormous freedom in tailoring their polarization properties. Here we use this freedom to generate photon pairs with tunable polarization entanglement via spontaneous parametric downconversion (SPDC) in a 400-nm GaP film. By changing the pump polarization, we tune the polarization state of photon pairs from maximally entangled to almost disentangled, which is impossible in a single bulk SPDC source. Polarization entanglement, together with the broadband frequency spectrum, results in an ultranarrow (12 fs) Hong-Ou-Mandel effect and promises extensions to hyperentanglement.

IMPROVING THE PERFORMANCE CHARACTERISTICS OF MACHINE PARTS BASED ON THE COMBINED INFLUENCE OF STRONG MAGNETIC FIELDS

Magnetic treatment is a promising method of hardening. Metal exposed to alternating magnetic fields changes the performance properties of the surface layer of a combination of magnetic and ultrasonic effects, provides a combined method of processing and strengthening surfaces of machine parts, which eliminates the main disadvantages of magnetic and electrical hardening — instability of physical and mechanical properties of this layer with detail.
 The purpose of the work is to investigate the possibility of improving the performance of machine parts based on the combined effect of strong magnetic fields.
 The study of the use of a uniform flux of magnetic fields generated by powerful permanent magnets was performed to affect the material volume of non-grinding plates of the cutting tool CNMG_120508E-M. The effect of uniform magnetic flux is initiated as a result of resonant oscillations of the sample caused by broadband exposure of equal amplitude by means of a "white noise" generator and a piezo emitter.
 The authors found that as a result of volumetric strengthening of non-grinding plates of carbide cutting tools, by exposure to polyfrequency oscillations in the form of a broadband frequency spectrum of equal amplitudes, a significant reduction in dimensional wear of the plates is achieved. Adding mechanical vibrations to the samples in a uniform constant magnetic field allowed to achieve volumetric hardening of the samples from 150 HB to 240 ÷ 250 HB, ie 60 ÷ 65% in 10—12 minutes, which is the hardening of the samples by 5—6% in one minute.
 The work on determining the relationship of changing properties with processing time, frequency range, amplitude and other modes to find the optimal values ​​of processing parameters, has great prospects for the ability to obtain a set of performance characteristics, control external and internal properties of products.

Composite trampoline metamaterial with enlarged local resonance bandgap

The engineered resonance phenomena by artificial structures have opened a new frontier in modern science and technology. Artificial structures such as pillared phononic crystals and metamaterials are emerging domain due to their surface resonance features that are governed by periodic array of pillars embedded on a host plate. The dual aspects of pillared structure exhibiting both Bragg and local resonance bandgaps make it a prominent choice for wave manipulation in general and vibration isolation in particular. The present study proposes pillared-plate structure based composite trampoline metamaterial that can exhibit ultrawide local resonance bandgap with relative bandwidth around 100%, confirmed by numerical and experimental approaches. The study establishes that composite nature of the pillar together with trampoline effect caused by drilling periodic array of holes in the host plate can enhances the effective mass density and reduce the plate stiffness, respectively that eventually lead to enlarged local resonance bandgap. The evolution of composite design with trampoline effect from parent pillar-plate structure is also fully discussed through wave dispersion and frequency response studies, and the widening of local resonance bandgap is demonstrated. By a parametric study, the effect of geometric parameters on the reported bandgaps is elaborated. Both numerical and experimental results validate the effectiveness of composite trampoline pillar-plate structure in attenuating bulk waves over broadband frequency spectrum. The new findings reported here provide another perspective on the dynamical characteristics and usefulness of pillared metamaterials for wave manipulation and subwavelength vibration attenuation.

Medical examinations for office employees

The transition of the Russian Federation to new regulations in the field of labor protection in 2021 requires preliminary and periodic medical examinations of about 30–40 million office employees, which creates a number of organizational and economic problems for employers. The basis for conducting medical examinations of office personnel is the presence at the workplace of the electromagnetic field of the broadband frequency spectrum (5 Hz — 2 kHz, 2 kHz — 400 kHz), which is considered as a prerequisite for the appearance of occupational diseases associated with the influence of the electromagnetic field, leading to a disorder of the autonomic (autonomous) nervous system and with visually strenuous work, leading to the appearance of progressive myopia. The order of the Ministry of Health of the Russian Federation No. 29n of 28.01.2021 does not contain the exceptions characteristic of the latest editions of the order of the Ministry of Health and Social Development of the Russian Federation No. 302n concerning the intensity of the impact of the factor «when exceeding the maximum permissible level» or «work on reading, entering information, working in the dialog mode in the amount of at least 50 % of the working time», which means that the employer must conduct medical examinations of office employees working with a PC. The number of necessary laboratory and functional tests decreased by 1.8 times. Paradoxical is the transfer from the order of the Ministry of Health and Social Development (No. 302n) to the new order of the Ministry of Health of the Russian Federation (No. 29n) of the connection of electromagnetic fields exclusively with ophthalmological problems, ignoring no less significant problems of damage to the nervous system. The inclusion of a dermatovenerologist in the commission is completely unjustified, since the impact of the electromagnetic field of the broadband frequency spectrum does not cause significant problems of the dermatovenerological profile. Taking into account the requirements of the order of the Ministry of Health and Social Development No. 417n, it was proposed to replace a dermatovenerologist with a psychotherapist in the composition of the commission for conducting medical examinations of office employees with a psychotherapist with the inclusion in the table «Frequency and volume of mandatory preliminary and periodic medical examinations of employees» of the Appendix of the order of the Ministry of Health No. 29n of laboratory and functional studies of a psychotherapeutic profile.

Hypersonic Boundary-Layer Receptivity over a Blunt Cone to Freestream Pulse Disturbances

Although receptivity plays a key role in the transition of hypersonic flows, most prior computational receptivity studies have neglected to study broadband frequency disturbance spectra. This work uses perfect gas linear stability theory (LST) and direct numerical simulation (DNS) to study the receptivity of flow over a 9.525 mm nose radius, 7 deg half-angle straight cone at Mach 10 using finite spherical and planar pulses to approximate disturbances with broadband frequency spectra. Freestream fast acoustic, slow acoustic, temperature, and vorticity pulses of both geometries were studied to investigate a wide range of forcing conditions. Unsteady DNS predicts second mode growth and agrees well with LST. DNS and LST data are used to extract second mode receptivity coefficients and phase spectra. For the finite pulses the strongest to weakest responses are for the fast acoustic, temperature, slow acoustic, and vorticity pulses, respectively. The planar disturbances show the strongest response for the slow acoustic, temperature, vorticity, and fast acoustic pulses in that order. Fast Fourier transform results show significant variation in the spectral disturbance response between disturbance types and geometries, and the planar fast acoustic pulse in particular is shown to much more readily excite modal disturbances other than the primary second mode.

A Turbulence Model Assessment for Deep Part Load Conditions of a Francis Turbine

Today, hydropower plants received increased attention as they have the ability to stabilize the electrical grid. However, this is accompanied by more start-stop sequences as well as operation in off-design conditions. One big task is to develop improved runner designs that can resist the increased pressure fluctuations. In the scope of this study, a Francis turbine is simulated for a deep part load operating point with the use of the SAS model and the more recently developed SBES model with ANSYS CFX. Both turbulence models are hybrid RANS-LES models. The simulation results are compared against model test data from a measurement at high cavitation number. For the evaluation of the pressure fluctuations comparison is furthermore made against experimental data at low cavitation number. All in all, SAS and SBES model predict similar flow characteristics. Both, the velocity profiles in the PIV measurement plane and the predicted pressure fluctuations, show only minor differences. The comparison against experimental data shows that the amplitude of the broadband frequency spectrum, which results from the occurrence of vortices, is overestimated at the investigated locations on the runner blades.

Multimodal pizza-shaped piezoelectric vibration-based energy harvesters

Energy harvesting from ambient vibration through piezoelectric devices has received a lot of attention in recent years from both academia and industry. One of the main challenges is to develop devices capable of adapting to diverse sources of environmental excitation, being able to efficiently operate over a broadband frequency spectrum. This work proposes a novel multimodal design of a piezoelectric energy harvesting system to harness energy from a wideband ambient vibration source. Circular-shaped and pizza-shaped designs are employed as candidates for the device, comparing their performance with classical beam-shaped devices. Finite element analysis is employed to model system dynamics using ANSYS Workbench. An optimization procedure is applied to the system aiming to seek a configuration that can extract energy from a broader frequency spectrum and maximize its output power. A comparative analysis with conventional energy harvesting systems is performed. Numerical simulations are carried out to investigate the harvester performances under harmonic and random excitations. Results show that the proposed multimodal harvester has potential to harness energy from broadband ambient vibration sources presenting performance advantages in comparison to conventional single-mode energy harvesters.

Phononic metastructures with ultrawide low frequency three-dimensional bandgaps as broadband low frequency filter

Vibration and noise control are among the classical engineering problems that still draw extensive research interest today. Multiple active and passive control techniques to resolve these problems have been reported, however, the challenges remain substantial. The recent surge of research activities on acoustic metamaterials for vibration and noise control are testimony to the fact that acoustic metamaterial is no longer limited to pure theoretical concepts. For vibration and noise control over an ultrawide frequency region, 3-D metastructures emerge as a novel solution tool to resolve this problem. In that context, the present study reports a novel proposal for 3-D monolithic phononic metastructures with the capability to induce low frequency ultrawide three-dimensional bandgaps with relative bandwidth enhancements of 157.6% and 160.1%. The proposed monolithic metastructure designs consist of elastic frame assembly that is connected with the rigid cylindrical masses. Such structural configuration mimics monoatomic mass-spring chain where an elastic spring is connected with a rigid mass. We develop an analytical model based on monoatomic mass-spring chain to determine the acoustic mode frequency responsible for opening the bandgap. The wave dispersion study reveals the presence of ultrawide bandgaps for both types of metastructures. The modal analysis shows distribution of vibration energy in the bandgap opening (global resonant mode) and closing (local resonant mode) bounding edges. We further analyze the band structures and discuss the physical concepts that govern such ultrawide bandgap. Vibration attenuation inside the bandgap frequency range is demonstrated by frequency response studies conducted by two different finite element models. Thanks to additive manufacturing technology, 3-D prototypes are prepared and low amplitude vibration test is performed to validate the numerical findings. Experimental results show the presence of an ultrawide vibration attenuation zone that spreads over a broadband frequency spectrum. The bandgaps reported by the proposed metastructures are scale and material independent. The research methodology, modelling and design strategy presented here may pave the way for the development of novel meta-devices to control vibration and noises over a broadband frequency range.