The thesis is aimed at developing the design and manufacturing of metalcomposite hybrid structural assemblies. For this purpose an aeronautical structured was selected, in detail a component of an helicopter, that is actually manufactured by assembling a metallic component to a composite one. At first the component was designed in order to obtain a similar compositemetal hybrid structure, analyzing the aspects related with the technologic and manufacturing feasibility, and embedding the linking metallic part within the composite component during the manufacturing process. Resin Transfer Moulding technology was used for the component manufacturing. This closed-mould technology allows to easily incorporate the metallic structure within the composite component, allowing a good adhesion between the different materials thanks to the possibility to fill the empty spaces during resin injection at pressure. This analysis has been carried out by means of a building-block approach: as a first step, hybrid coupons have been manufactured, then, once tested and evaluated any metal-composite adhesive behaviour occured to them, a set of sub-components resembling the full-scale structure has been designed and developed. All manufacturing and development phases have been enhanced thanks to numerical simulation software, such as LS-Dyna® for structural analysis and Esi PAM-RTM 2008® for for numerical flow simulations. Last remark of this project comes from the feasibility study on manufacturing a hybrid laminate PPS-Carbon-Aluminium by means of induction-welding method, a design choice taken after evaluating several different techniques to develop hybrid components. This analysis provided a full set of data for what concerns the first heating of the material only, as this process had to be stopped due to the technological limits of the available machine. However, the results gathered from this experience proved to be very useful in order to define any needed change on the welding machine, so that this can be enabled to perform hybrid molding.
In questo lavoro di tesi è stato affrontato il problema inerente la progettazione e la realizzazione di assiemi strutturali ibridi in metallo-composito. A tal proposito è stata individuata una struttura aeronautica e, precisamente, elicotteristica, attualmente realizzata mediante il collegamento meccanico di una parte in composito con una metallica. In primo luogo è stata effettuata la progettazione dello stesso componente in modo da definire un'analoga struttura ibrida metallo-composito, affrontando gli aspetti legati alla fattibilità tecnologica e realizzativa e prevedendo di inglobare la parte metallica di collegamento all'interno del componente in composito durante il processo di laminazione. La tecnologia individuata per la realizzazione del componente è stata il Resin Transfer Moulding. Tale tecnologia a stampo chiuso permette infatti di inglobare facilmente l'inserto metallico all'interno della struttura in composito, consentendo un intimo contatto tra i diversi materiali anche grazie alla possibilità di riempire eventuali spazi vuoti in fase di iniezione della resina in pressione. Lo studio è stato affrontato mediante uno schema di tipo building-block approach, partendo dalla realizzazione e dal testing di coupon ibridi per la valutazione delle proprietà di adesione metallo-composito per arrivare alla realizzazione di sub-components rappresentativi della struttura full-scale. Tutte le fasi di sviluppo sono state supportate da simulazioni numeriche, avvalendosi del software LS-Dyna® per le analisi strutturali e di Esi PAM-RTM 2008® per lo studio del flusso di resina. Per finire, valutando la possibilità di utilizzare diverse tecnologie realizzative per la produzione di componenti ibridi, è stata presa in esame l'eventualità di creare un laminato ibrido PPS-Carbonio-alluminio sfruttando la tecnologia di induction-welding. Tale studio, però, ha fornito i dati relativi ad un primo riscaldamento ma si è dovuto interrompere per limiti tecnologici dati dalla macchina a disposizione. Ad ogni modo i risultati di queste attività sono serviti a definire le modifiche richieste alla macchina di saldatura per consentire la realizzazione di saldature ibride.
Progettazione e realizzazione di assiemi strutturali ibridi metallo-composito in applicazioni aerospaziali
MICELLI, GAETANO
2012/2013
Abstract
The thesis is aimed at developing the design and manufacturing of metalcomposite hybrid structural assemblies. For this purpose an aeronautical structured was selected, in detail a component of an helicopter, that is actually manufactured by assembling a metallic component to a composite one. At first the component was designed in order to obtain a similar compositemetal hybrid structure, analyzing the aspects related with the technologic and manufacturing feasibility, and embedding the linking metallic part within the composite component during the manufacturing process. Resin Transfer Moulding technology was used for the component manufacturing. This closed-mould technology allows to easily incorporate the metallic structure within the composite component, allowing a good adhesion between the different materials thanks to the possibility to fill the empty spaces during resin injection at pressure. This analysis has been carried out by means of a building-block approach: as a first step, hybrid coupons have been manufactured, then, once tested and evaluated any metal-composite adhesive behaviour occured to them, a set of sub-components resembling the full-scale structure has been designed and developed. All manufacturing and development phases have been enhanced thanks to numerical simulation software, such as LS-Dyna® for structural analysis and Esi PAM-RTM 2008® for for numerical flow simulations. Last remark of this project comes from the feasibility study on manufacturing a hybrid laminate PPS-Carbon-Aluminium by means of induction-welding method, a design choice taken after evaluating several different techniques to develop hybrid components. This analysis provided a full set of data for what concerns the first heating of the material only, as this process had to be stopped due to the technological limits of the available machine. However, the results gathered from this experience proved to be very useful in order to define any needed change on the welding machine, so that this can be enabled to perform hybrid molding.| File | Dimensione | Formato | |
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2013_12_Micelli.pdf
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Descrizione: Testo della tesi
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https://hdl.handle.net/10589/87103