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Preliminary experimental/numerical study of the vibration annoyance control of a windshield wiper mechanical system through a Synchronized Switch Shunt Resonator (SSSR) technology

Viscardi M., Di Leo R., Ciminello M., Brandizzi M.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 1

283--296

EN

The present work focuses on the study and analysis of vibrations generated by the electrical motor of a wiper system on its support bracket referring to an hatchback vehicle passenger car. In the electric motor of the wiper system there can be present an imbalance transmitting vibrations to the main body via the support bracket. In this paper, after a short resume of available synchronized switch shunt damping methods, a preliminary experimental evaluation of their potential performance on noise control of the wiper system is reported. After preliminary experimental measurements of dynamic vibration by the use of vibrometer laser both on the real hatchback car then in laboratory environment, a numerical model has been created to evaluate deformations of the support bracket for comparison with the experimental data. This work realizes the preliminary numerical/experimental characterization activity to set up a new application of a control system based on a semi-active technique, called Synchronized Switch Shunt Resonator (SSSR).

2

Skin-Spar Failure Detection of a Composite Winglet Using FBG Sensors

Ciminello M., Fenza A. de, Dimino I., Pecora R.

Archive of Mechanical Engineering

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2017

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Vol. LXIV, nr 3

287--300

EN

Winglets are introduced into modern aircraft to reduce wing aerodynamic drag and to consequently optimize the fuel burn per mission. In order to be aerodynamically effective, these devices are installed at the wing tip section; this wing region is generally characterized by relevant oscillations induced by flights maneuvers and gust. The present work is focused on the validation of a continuous monitoring system based on fiber Bragg grating sensors and frequency domain analysis to detect physical condition of a skin-spar bonding failure in a composite winglet for in-service purposes. Optical fibers are used as deformation sensors. Short Time Fast Fourier Transform (STFT) analysis is applied to analyze the occurrence of structural response deviations on the base of strain data. Obtained results showed high accuracy in estimating static and dynamic deformations and great potentials in detecting structural failure occurrences.

3

Fourier expansion solution for a switched shunt control applied to a duct

Ameduri S., Ciminello M.

Journal of Theoretical and Applied Mechanics

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2010

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Vol. 48 nr 2

479-504

EN

In the present work, a semi analytic approach aimed at estimating the effects on reduction of the pressure sound level by synchronised switched shunt logic is described. The displacement field within a 1D longitudinal air column through a Fourier series expansion has been formalised by assigning a sinusoidal perturbation and fluid-structure interface condition on the left and right boundaries, respectively. To simulate the no control operative condition, the solution has been computed for the entire time domain, keeping invariant all circuitry properties; then for the switch working modality, the solution has been computed by splitting the entire time domain into partitions; for any partition, specific circuitry properties (e.g. piezo voltage, electrical field...) have been selected. Based on the displacement information, the related sound pressure level has been compared for no controlled and controlled operative conditions, with and without signal amplification.

PL

W pracy zaprezentowano pół-analityczne rozwiązanie zagadnienia redukcji poziomu ciśnienia akustycznego w przewodzie za pomocą zsynchronizowanej metody bocznikowania. Opis pola przemieszczeń wewnątrz jednowymiarowej kolumny powietrza sformalizowano rozwinięciem w szereg Fouriera przy uwzględnieniu sinusoidalnie zmiennych zaburzeń na prawym i lewym brzegu przewodu. Dla przypadku z wyłączonym układem sterowania rozwiązanie obliczono w całej dziedzinie czasu przy utrzymaniu stałych parametrów obwodu elektrycznego, natomiast dla trybu sterowanego dokonano analizy, dzieląc przedział czasu na fragmenty. W każdym z nich charakterystyczne cechy układu sterowania (np. napięcie przykładane do piezoelektryków, natężenie pola elektrycznego...) dobrano w odpowiedni sposób. Na podstawie obserwacji przemieszczeń porównano poziom ciśnienia akustycznego dla warunków z wyłączonym i włączonym sterowaniem oraz z i bez wzmocnienia sygnału.