This thesis work illustrates a study on the performance of an axisymmetric corrugated laminate used as a flexible joint. This component both withstands a certain torque value and, at the same time, should be compliant in bending, so to be able to work in the presence of a misalignment. This thesis shows the geometries selected for preliminary analysis. A code for automatic generation of FE model is also described, which was designed to evaluate the different con figurations of the components with respect to the performance required for the components. The code is able to generate a con figuration by varying all the parameters involved in determining the components geometry. Given the constraints deriving from the input data, two basic geometries have chosen considering a corrugated axysimmetric laminate with different axes of revolution. These two basic geometries are called tubolar and disk geometries, both the tubular and the disk geometries have been analyzed, by varying from time to time the main geometrical parameters such as corrugation pitch, depth of corrugation and laminate thickness. Based on the results gradually obtained and the characteristics of each geometry, peculiar lamination strategies have been implemented. In the initial phase of the analysis, an efficiency parameter has been used to compare the performance of different con figurations with respect to the input data of the project. This efficiency parameter is equal to the ratio between the torsional buckling load and bending stiffness. The con figurations that express the highest efficiency value are the ones that perform the flexible joint function at best. Therefore these have been analyzed in a further phase of the study: the automatic generation code has been applied by imposing loads equal to the nominal ones. This is aimed at obtaining the maximum deflection angle that can be achieved by the component when subjected to the required torsional load. The design problem considered in this analysis is characterized by very high torque values applied to the joint. In such a condition the angle that can be obtained by the joint without failures is of the order of few degrees. The full potential of this technology has emerged. The geometrical parameters that most influence the performance have been identified and, acting on these, it is possible to obtain components capable of transmitting high torques and bearing signifi cant misalignment angles.
Questo lavoro di tesi presenta uno studio sulle prestazioni di un laminato corrugato assialsimmetrico utilizzato come giunto flessibile. Questo componente deve essere in grado di sopportare un determinato valore di momento torcente e, al tempo stesso, di flettere. Nel corso della relazione vengono presentate le geometrie base selezionate per le analisi preliminari. Viene inoltre descritto il codice per la generazione automatica dei modelli FEM ideato per la valutazione dei componenti rispetto alle prestazioni richieste dai dati in ingresso di questo progetto, spiegando tutti i parametri coinvolti nella determinazione della geometria dei componenti e nelle varie simulazioni strutturali previste. Guardando i vincoli imposti dai dati in ingresso sono state scelte due geome- trie base: queste vengono ottenute cambiando l'asse di rivoluzione, in seguito alla determinazione del pro filo corrugato. Le due geometrie base vengono rispettiva- mente defi nite come geometria tubolare e a disco. Su entrambe le geometrie base vengono svolte numerose analisi facendo variare i parametri geometrici principali quali, passo di corrugazione, profondità di corrugazione e spessore del laminato, dando vita a numerose con figurazioni differenti. Per ogni geometria fondamen- tale vengono introdotte speci che strategie di laminazione seguendo i risultati via via ottenuti e le caratteristiche delle singole geometrie. Nella fase iniziale dell'analisi viene utilizzato un parametro di efficienza pen- sato per poter paragonare le prestazioni di diverse con gurazioni rispetto all'obiettivo fi nale, ovvero il raggiungimento dei dati di progetto. Questo parametro di efficienza è uguale al rapporto tra il carico di instabilità a torsione e la rigidezza flessionale. Le con figurazioni che presentano il valore più elevato sono quelle che più si avvicinano alla funzionalità di giunto flessibile. In una fase successiva dell'analisi le con figurazioni migliori sono state sottoposte nuovamente alle analisi strutturali ponendo i carichi applicati uguali a quelli nominali imposti dal progetto, per ottenere il massimo angolo di disallineamento raggiungibile. Alla fine di queste analisi è emerso il potenziale di questa tecnologia. Agendo sui parametri geometrici più influenti sulle prestazioni, descritti nel corso di questa tesi, si possono ottenere componenti in grado di trasmettere coppie elevate sopportando angoli di flessione altrettanto importanti.
Numerical studies for the development of a flexible joint in corrugated composite laminate
COLOMBO, FABIO
2018/2019
Abstract
This thesis work illustrates a study on the performance of an axisymmetric corrugated laminate used as a flexible joint. This component both withstands a certain torque value and, at the same time, should be compliant in bending, so to be able to work in the presence of a misalignment. This thesis shows the geometries selected for preliminary analysis. A code for automatic generation of FE model is also described, which was designed to evaluate the different con figurations of the components with respect to the performance required for the components. The code is able to generate a con figuration by varying all the parameters involved in determining the components geometry. Given the constraints deriving from the input data, two basic geometries have chosen considering a corrugated axysimmetric laminate with different axes of revolution. These two basic geometries are called tubolar and disk geometries, both the tubular and the disk geometries have been analyzed, by varying from time to time the main geometrical parameters such as corrugation pitch, depth of corrugation and laminate thickness. Based on the results gradually obtained and the characteristics of each geometry, peculiar lamination strategies have been implemented. In the initial phase of the analysis, an efficiency parameter has been used to compare the performance of different con figurations with respect to the input data of the project. This efficiency parameter is equal to the ratio between the torsional buckling load and bending stiffness. The con figurations that express the highest efficiency value are the ones that perform the flexible joint function at best. Therefore these have been analyzed in a further phase of the study: the automatic generation code has been applied by imposing loads equal to the nominal ones. This is aimed at obtaining the maximum deflection angle that can be achieved by the component when subjected to the required torsional load. The design problem considered in this analysis is characterized by very high torque values applied to the joint. In such a condition the angle that can be obtained by the joint without failures is of the order of few degrees. The full potential of this technology has emerged. The geometrical parameters that most influence the performance have been identified and, acting on these, it is possible to obtain components capable of transmitting high torques and bearing signifi cant misalignment angles.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/165172