High Resolution Wavenumber Analysis (HRWA) for the mechanical characterisation of viscoelastic beams

Margerit, Pierre; Lebée, Arthur; Caron, Jean; Boutillon, Xavier

doi:10.1016/j.jsv.2018.06.062

Cited by 14 publications

(8 citation statements)

References 40 publications

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“…If the mass of the wire sections between nozzles and the workpiece ( h 1 + h 2 ), which is varied in the range of 3–5 mm ( H’ n - H n ), and the mass losses on tool-electrode wear [143, 144, 145, 146] are neglected, then the amplitude of oscillation of the wire tool may be expressed as a complex amplitude of the harmonic signal [147, 148, 149, 150, 151]:Aˆn=A0·etrueβ¯τ,where A 0 is the amplitude in the direction of wire feed, which is limited by the discharge gap Δ and is less than Δ, A n ≤ A 0 for stable EDM, βtrue¯ is the damping coefficient expressed as a complex number in the form a + bi , and τ is the period of oscillation T .…”

Section: Resultsmentioning

confidence: 99%

Electrical discharge machining of ceramic nanocomposites: sublimation phenomena and adaptive control

Grigoriev

Kozochkin

Porvatov

et al. 2019

Heliyon

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The productivity of electrical discharge machining (EDM) is relatively low owing to the natural laws of electrical erosion. Precise EDM demands uninterrupted control of the discharge gap and adjustment of process parameters. It is particularly critical for processing large workpieces with complex linear surfaces and for materials with threshold conductivities such as the new advanced ceramic nanocomposites Al2O3+TiC and Al2O3+SiCw+TiC(30–40%). In these cases, adequate flushing of erosion products is hampered by the geometry of the working space or by the small value of the required discharge gap, which does not exceed 2.2–2.5 μm. The methods of adaptive control in modern computer numerical control systems of EDM equipment based on measuring the electrical parameters in the working zone have been shown to be ineffective in the cases described above. This study aims to investigate the natural phenomena of material sublimation under discharge pulses for conductive ceramics and nanocomposites. The measured conductivities of the samples are higher than the percolation threshold. However, the question of machinability remains open owing to detected processing interruptions and poor quality of machined surfaces. New knowledge on EDM of conductive ceramics and nanocomposites can improve the final quality of the machined surfaces and productivity of the method by the introduction of advanced monitoring and control methods based on acoustic emissions. The manuscript presents an up-to-date overview and current state of the research on the subject area. The obtained morphology of the samples and discussion of the findings complete the experimental part of the study. The scientific basis for a new type of adaptive control system is provided. This can improve the effectiveness of parameter control for machining conductive ceramics and nanocomposites and contribute to an increase in the EDM performance for the most critical cases.

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Section: Resultsmentioning

confidence: 99%

Electrical discharge machining of ceramic nanocomposites: sublimation phenomena and adaptive control

Grigoriev

Kozochkin

Porvatov

et al. 2019

Heliyon

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“…The procedure is applied to the harmonic response of the orthotropic composite plate sample, studied in 3.1, at the frequency of 250 Hz (Figure 2.(a)). The ESTER criterion (inverse of the geometrical mean of the estimation errors) is computed for r ∈ [ [ 1,30 ]] ( Figure 2). A maximum of the criterion can be observed for R = 4.…”

Section: Wavevector Extractionmentioning

confidence: 99%

“…In a recent article [1], the authors proposed the High Resolution Wavenumber Analysis method (HRWA). Using the ESPRIT algorithm with the ESTER criterion, it allows to extract wavenumbers in the harmonic response of a beam.…”

Section: Introductionmentioning

confidence: 99%

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The High-Resolution Wavevector Analysis for the characterization of the dynamic response of composite plates

Margerit

Lebée

Caron

et al. 2019

Journal of Sound and Vibration

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The High Resolution Wavevector Analysis (HRWA) is presented and its application illustrated. Extending the High Resolution Wavenumber Analysis method [1] to 2D signals, it allows the wide-band and local characterization of the linear elastic behavior of anisotropic plates. The method belongs to the family of experimental wavenumber-based characterization methods and uses the high resolution signal processing algorithm ESPRIT (Estimation of Signal Parameters via Rotational Invariance Techniques) and the ESTER criterion (ESTimation of ERror) to overcome some of the limitation of Fourier-based methods. Three experimental applications on composite plate specimens are presented. First (i), from the out-of-plane velocity field of a sandwich plate with a foam core, different wave types (bending, shear and compression) are extracted. The results are compared with numerical predictions. Second (ii), individual layer contributions are separated on a honeycomb sandwich plate by means of the observation of the dependence of the extracted complex wavevectors as a function of wave propagation direction and frequency. Third (iii), a local wavenumber extraction is performed on a 4-layer carbon-epoxy plate made of fiber patches with spatially varying orientations. The local specific bending stiffness of the plate is identified from the extracted wavevectors and compared with theoretical results.

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“…Similarly, the VFM (Virtual Field Method) [21,22], the pressure is estimated with virtual displacement and curvature fields. In another recent approach, Margerit et al developed a promising characterisation method using ESPRIT algorithm to extract complex wavevector for 1D [23] and 2D [24] structures in wide frequency range.…”

Section: Introductionmentioning

confidence: 99%

On the structural dynamics of laminated composite plates and sandwich structures; a new perspective on damping identification

Marchetti

Ege

Leclère

et al. 2020

Journal of Sound and Vibration

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This paper presents the modelling and the dynamic characterization of laminated composite plates and sandwich structures in terms of stiffness and damping. The developments used in this paper are based on the analytical multilayer model of Guyader and Lesueur (JSV, 1978). The model considers linear shear, membrane and bending effects in each layer. The characteristics of the structure are determined by means of an equivalent thin plate methodology. The first main novelty of this paper consists in adapting this methodology for laminated plates (orthotropic multilayers with arbitrary orthotropic angle per layer). An experimental validation of this adaptation is presented for a laminated composite plate. Concerning the modelling of the structural loss factor, a space domain definition based on the spatial attenuation of a plane wave is compared to an energetic method and an equivalent definition based on the thin plate theory. The results show that the equivalent definition overestimates the loss factor in high frequencies since the thin plate theory only considers the flexural behaviour of the structure. On the contrary, the space domain definition (which give similar results as compared to the energetic one for lightly damped structures) considers the frequency dependent variation of the dynamic behaviour of the structure by means of the ratio between the group and phase velocities. The latter approach is considered to be more correct. The second main novelty of this article is on the experimental validation of this space domain definition. The structural loss factors of two sandwich structures are Article published in Journal of Sound and Vibration identified from measurements using modal, energetic and spatial methods. The results using the space domain definition are in very good agreement with the analytical predictions and the estimations of the modal and energetic methods for both plates for a large frequency band (up to 20 kHz), demonstrating the validity of the approach developed in this paper.

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High Resolution Wavenumber Analysis (HRWA) for the mechanical characterisation of viscoelastic beams

Cited by 14 publications

References 40 publications

Electrical discharge machining of ceramic nanocomposites: sublimation phenomena and adaptive control

Electrical discharge machining of ceramic nanocomposites: sublimation phenomena and adaptive control

The High-Resolution Wavevector Analysis for the characterization of the dynamic response of composite plates

On the structural dynamics of laminated composite plates and sandwich structures; a new perspective on damping identification

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