The aim of the thesis is the development and test of a multi-modal adaptive tuned mass damper based on piezoelectric shunt. The multi-modal adaptive TMD consists in a beam of steel, with two glued piezoelectric patches, able to control two resonating frequencies at a time. First, the theory related to the piezoelectric shunt, applied for the vibrations control, is clarified. Following, a first tuning of the electro-mechanical system is performed as function of the assumed position by the piezoelectric patches. For each possible geometrical configuration, the modal parameters estimation is carried out. This step is preparatory for the simulation of the single degree of freedom model (SDOF) and the multi degree of freedom model (MDOF). Then, three of the possible configurations are picked for the numerical simulations. The SDOF model is numerically simulated for each geometrical layout and for each possible configuration according to the negative capacitances connection: series-series, series-parallel, parallel-series, parallel-parallel. According to some considerations based on the Modal Electro-Mechanical Coupling Factor (MEMCF), supported by the results coming from the SDOF model simulation, the configuration to be tested is chosen. Once the definitive geometrical layout is selected, the MDOF model is numerically simulated. The comparison between the numerical results of the two models allows to properly quantify the effect of the modal superimposition. The numerical results are validated by the experimental tests. Besides, the experiments aim to highlight the potentiality of this technique in terms of maximum and minimum percentage shift of the resonating frequencies under study, and to show the flexibility in terms of capability to move independently one resonating frequency keeping the other one fixed.
L'obiettivo della tesi è lo sviluppo ed il test di un tuned mass damper (smorzatore a massa accordata) mutimodale adattivo basato su shunt piezoelettrico. Il TMD adattivo multimodale costruito consiste in una barretta di acciaio con due cerotti piezoelettrici incollati, tramite i quali è possibile controllare due frequenze di risonanza alla volta. In primo luogo viene chiarita la teoria relativa allo shunt piezoelettrico, utilizzato per il controllo delle vibrazioni. Successivamente, viene eseguito un primo tuning del sistema elettromeccanico in funzione della posizione assunta dai cerotti piezoelettrici. Per ogni possibile configurazione geometrica sono stimati i parametri modali, da inserire nei modelli a singolo grado di libertà (SDOF) e multi grado di libertà (MDOF); tre dei possibili layout vengono selezionati per le simulazioni numeriche. Il modello SDOF è simulato numericamente per ogni layout geometrico e per ogni opzione di collegamento con le capacità negative: serie-serie, serie-parallelo, parallelo-serie, parallelo-parallelo. La configurazione da testare è scelta secondo alcune considerazioni basate sul Modal Electro-Mechanical Coupling Factor (MEMCF), supportate dai risultati ottenuti nella simulazione del modello SDOF. Una volta selezionato il layout geometrico definitivo, il modello MDOF è simulato numericamente. Il confronto tra i risultati numerici dei due modelli permette di quantificare adeguatamente l'effetto della sovrapposizione modale. I risultati ottenuti dalle simulazioni numeriche sono validati da prove sperimentali. Inoltre, le sperimentazioni, evidenziano la potenzialità di questa tecnica in termini di spostamento percentuale massimo e minimo delle frequenze di risonanza sotto analisi, e mostrano la flessibilità in termini di capacità di muovere indipendentemente una frequenza di risonanza mantenendo l'altra fissa.
Development and test of a multi-modal adaptive tuned mass damper based on piezoelectric shunt
Boccuto, Francesco
2020/2021
Abstract
The aim of the thesis is the development and test of a multi-modal adaptive tuned mass damper based on piezoelectric shunt. The multi-modal adaptive TMD consists in a beam of steel, with two glued piezoelectric patches, able to control two resonating frequencies at a time. First, the theory related to the piezoelectric shunt, applied for the vibrations control, is clarified. Following, a first tuning of the electro-mechanical system is performed as function of the assumed position by the piezoelectric patches. For each possible geometrical configuration, the modal parameters estimation is carried out. This step is preparatory for the simulation of the single degree of freedom model (SDOF) and the multi degree of freedom model (MDOF). Then, three of the possible configurations are picked for the numerical simulations. The SDOF model is numerically simulated for each geometrical layout and for each possible configuration according to the negative capacitances connection: series-series, series-parallel, parallel-series, parallel-parallel. According to some considerations based on the Modal Electro-Mechanical Coupling Factor (MEMCF), supported by the results coming from the SDOF model simulation, the configuration to be tested is chosen. Once the definitive geometrical layout is selected, the MDOF model is numerically simulated. The comparison between the numerical results of the two models allows to properly quantify the effect of the modal superimposition. The numerical results are validated by the experimental tests. Besides, the experiments aim to highlight the potentiality of this technique in terms of maximum and minimum percentage shift of the resonating frequencies under study, and to show the flexibility in terms of capability to move independently one resonating frequency keeping the other one fixed.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/182258