Μη Γραμμική ανάλυση κελυφών με εφαρμογές στην ανάλυση πολλαπλών κλιμάκων.

Sotiropoulos, Gerasimos; Σωτηρόπουλος, Γεράσιμος

dc.contributor.author	Sotiropoulos, Gerasimos	el
dc.contributor.author	Σωτηρόπουλος, Γεράσιμος	en
dc.date.accessioned	2021-09-29T09:35:03Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/53908
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.21606
dc.rights	Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/gr/	*
dc.subject	Ανάλυση φορέων Με πεπερασμένα στοιχεία	el
dc.subject	Κελύφη	el
dc.subject	Ανάλυση φορέων σε πολλαπλές κλίμακες	el
dc.subject	Λυγισμός	el
dc.subject	Ετερογενή υλικά	el
dc.subject	Multiscale Analysis	en
dc.subject	Finite element analysis	en
dc.subject	Shells	en
dc.subject	Buckling	en
dc.subject	Heterogeneous materials	en
dc.title	Μη Γραμμική ανάλυση κελυφών με εφαρμογές στην ανάλυση πολλαπλών κλιμάκων.	el
dc.title	Nonlinear finite element modeling of shells for multiscale analysis applications	en
heal.type	doctoralThesis
heal.classification	Υπολογιστική Μηχανική	el
heal.dateAvailable	2022-09-28T21:00:00Z
heal.language	el
heal.language	en
heal.access	embargo
heal.recordProvider	ntua	el
heal.publicationDate	2021-05-21
heal.abstract	In this thesis a formulation for multi-scale analysis of thin shells is presented. It is based on the first order homogenization theory and it allows for modeling, in a FE2 method's context, of thin shells that meet the Kirchhoff Love hypothesis. The shells exhibit a heterogeneous micro-structure consisting of nonlinear materials and cohesive interfaces that periodically repeats itself in the in plane and out of plane direction of the shell with respect to its mid-surface. The proposed methodology is then extended to shell structures that may undergo large deformations and strains and the same hypotheses are exploited for the periodicity of their heterogeneities and their size scale. Appropriate use of an attached coordinate system for the transformation of the utilized strain measures enables the neutralization of the moderately large rotations’ effect on the implementation of constraints at the RVE level, simplifying this way the boundary value problem to be solved at the micro-structural level. Emanating from Hill's averaging theorem, which is satisfied by use of appropriated averaging relations for thin shells, the principle of virtual work for thin Kirchhoff Love shells is formulated to account for those transformations and the expression of a consistent Stiffness Matrix is analytically derived. The proposed methodology is assessed against popular benchmarks for thin shells and its applicability is demonstrated in virtual testing of thin nanocomposite structures. Next the mechanical behavior of graphene reinforced nanocomposite structures is studied in a first order homogenization context. A simplified thin shell homogenization approach is followed for the modeling of graphene sheets with equivalent shell elements and a cohesive zone finite element model is utilized for modeling of the polymer graphene interaction. The effect of various characteristics of the micro structure such as the strength of the cohesive zone and geometry defects of the graphene sheets on the overall properties of the nanocomposite are under study.	en
heal.sponsor	Theauthor gratefully acknowledges the funding received towards the Ph.D from the European Council Advanced Grant MASTER - Mastering the computational challenges in numerical modeling and optimum design of CNT reinforced composites and from the European Regional Development Fund and Greek national funds under the Grant HEAT - Optimal multiscale design of innovative materials for heat exchange applications.	el
heal.advisorName	Παπαδόπουλος, Βησσαρίων
heal.committeeMemberName	Γαντές, Χαράλαμπος	el
heal.committeeMemberName	Σπηλιόπουλος, Κωνσταντίνος	el
heal.committeeMemberName	Τριανταφύλλου, Σάββας	el
heal.committeeMemberName	Νεραντζάκη, Μαρία	el
heal.committeeMemberName	Κουμούσης, Βλάσιος	el
heal.committeeMemberName	Φραγκιαδάκης, Μιχαήλ	el
heal.committeeMemberName	Παπαδόπουλος, Βησσαρίων	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Πολιτικών Μηχανικών. Τομέας Δομοστατικής. Εργαστήριο Στατικής και Αντισεισμικών Ερευνών	el
heal.academicPublisherID	ntua
heal.numberOfPages	137 σ.	el
heal.fullTextAvailability	false