The eco-sustainable engineering sector has, from the very beginning, tried to diversify and renovate the study of wind energy. As one of the most accessible renewable energy sources, several universities and laboratories research projects have been finalized or still being developed. Energy calculation models for the production of energy from renewable sources are generally coupled with static and dynamic models of structural calculation, both for turbines (VAWT and HAWT) and for support structures. This Thesis’ topic is that of presenting the structural analysis and the comparison of two support structures for a vertical axis wind turbine: a Hexagonal Pole and a Lattice Tower. In the first part of this dissertation, the acting loads are computed in stationary and operative turbine conditions, resulting from the action of the wind on the rotor blades. Secondly, in order to investigate the responses of the structures these forces are applied to the SAP2000 models. The results obtained are then verified and compared with the limit values of the current regulations. Specifically, they are affected by their own equations and safety coefficients in each condition. Additionally, from the critical analysis carried out to emphasize the peculiarities of the static and dynamical frequency response of the structures themselves, structural issues emerged. In particular, the resonance between the supports and the rotating machine appeared to lead to the evolution of relevant movements at the top. It is therefore essential to analyze the possible parameters that are involved in the damping action: such as, the types of junction between the elements and the interactions with the ground. A solution to overcome the possible problems arising from these displacements can be found in the reengineering of profiles and the weight of structures. This increases the overall stiffness of the system until a proper frequency, that exceeds the maximum excitation frequency and avoids resonance problems.
Il settore dell’ingegneria ecosostenibile, da sempre, ha tentato di diversificare e rinnovare lo studio dell’energia eolica. Come una delle fonti di energia rinnovabile più accessibile per l’uomo, svariate ricerche, in atenei e laboratori, sono state portate a termine o sono ancora in via di sviluppo. I modelli di calcolo energetici per la produzione di energia da fonti rinnovabili sono accompagnati da modelli statici e dinamici di calcolo strutturale, sia per quanto riguarda le turbine (VAWT e HAWT), sia per le strutture di sostegno. Questo lavoro di Tesi prende in considerazione l’analisi strutturale e la comparazione di due strutture di supporto per una turbina eolica ad asse verticale: un Palo Esagonale e un Traliccio. Nella prima parte di questo lavoro di Tesi, i carichi agenti sono stati calcolati in condizioni di turbina stazionaria e operativa, risultanti dall’azione del vento sulle pale del rotore. In secondo luogo, al fine di esaminare le risposte delle strutture, queste forze vengono applicate ai modelli di SAP2000. I risultati sono stati successivamente confrontati e verificati con i valori limite della normativa vigente, influenzati, in ogni condizione di applicazione, con determinate equazioni e coefficienti di sicurezza. Inoltre, dall’analisi critica effettuata per sottolineare le peculiarità della risposta statica e dinamica in frequenza delle strutture, sono emerse problematiche strutturali. In particolare, la risonanza tra i supporti e la turbina eolica sembrava portare all'evoluzione dei movimenti rilevanti nella parte superiore. È quindi essenziale analizzare i possibili parametri che sono coinvolti nell'azione di smorzamento: per esempio, i tipi di giunzione tra gli elementi e le interazioni con il terreno. Una soluzione per superare i possibili problemi derivanti da questi spostamenti si trova nella reingegnerizzazione dei profili e nel peso delle strutture. Ciò aumenta la rigidità complessiva del sistema, raggiungendo una frequenza naturale che supera quella massima di eccitazione, evitando problemi di risonanza.
Supporting structures for a vertical axis wind turbine : comparison between hexagonal poles and lattice towers
Massa, Federico
2019/2020
Abstract
The eco-sustainable engineering sector has, from the very beginning, tried to diversify and renovate the study of wind energy. As one of the most accessible renewable energy sources, several universities and laboratories research projects have been finalized or still being developed. Energy calculation models for the production of energy from renewable sources are generally coupled with static and dynamic models of structural calculation, both for turbines (VAWT and HAWT) and for support structures. This Thesis’ topic is that of presenting the structural analysis and the comparison of two support structures for a vertical axis wind turbine: a Hexagonal Pole and a Lattice Tower. In the first part of this dissertation, the acting loads are computed in stationary and operative turbine conditions, resulting from the action of the wind on the rotor blades. Secondly, in order to investigate the responses of the structures these forces are applied to the SAP2000 models. The results obtained are then verified and compared with the limit values of the current regulations. Specifically, they are affected by their own equations and safety coefficients in each condition. Additionally, from the critical analysis carried out to emphasize the peculiarities of the static and dynamical frequency response of the structures themselves, structural issues emerged. In particular, the resonance between the supports and the rotating machine appeared to lead to the evolution of relevant movements at the top. It is therefore essential to analyze the possible parameters that are involved in the damping action: such as, the types of junction between the elements and the interactions with the ground. A solution to overcome the possible problems arising from these displacements can be found in the reengineering of profiles and the weight of structures. This increases the overall stiffness of the system until a proper frequency, that exceeds the maximum excitation frequency and avoids resonance problems.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/175867