Προσομοίωση κατεργασίας HFMI  σε συγκολλήσεις GMAW  χάλυβα S700MC με την μέθοδο των πεπερασμένων στοιχείων

Λέκκας, Αριστείδης; Lekkas, Aristeidis

dc.contributor.author	Λέκκας, Αριστείδης	el
dc.contributor.author	Lekkas, Aristeidis	en
dc.date.accessioned	2023-08-24T11:07:31Z
dc.date.available	2023-08-24T11:07:31Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/57931
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.25628
dc.rights	Default License
dc.subject	Συγκολλήσεις	el
dc.subject	Χάλυβας υψηλής αντοχής	el
dc.subject	Παραμένουσες τάσεις	el
dc.subject	Συγκολλήσεις συμβολής	el
dc.subject	Μέθοδος απαλοιφής παραμενουσών τάσεων	el
dc.subject	Welding	en
dc.subject	GMAW	en
dc.subject	Butt joints	en
dc.subject	HFMI	en
dc.subject	Residual Stresses	en
dc.title	Προσομοίωση κατεργασίας HFMI σε συγκολλήσεις GMAW χάλυβα S700MC με την μέθοδο των πεπερασμένων στοιχείων	el
heal.type	bachelorThesis
heal.classification	Συγκολλήσεις	el
heal.language	el
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2023-06-16
heal.abstract	High Frequency Mechanical Impact treatment (HFMI) is a newer version of hammer and needle peening, where higher frequency impacts are employed, resulting in smaller spacing between the indentations. The main mechanisms favoring fatigue life improvement in welded components are the tensile residual stresses that usually exist at the weld toe due to welding are substituted by compressive residual stresses in the order of magnitude of the material yield strength, the transition from base to weld material is smoothened and the strain hardening that results from cold working, improve the fatigue resistance of the material at the weld toe. The method has gained popularity over conventional hammer peening, due to the greater treatment depths achieved, is user friendly and produces a uniform treated region with good repeatability. The beneficial effects of this PWT method on the fatigue life extension have been extensively reported in the literature. The fatigue life of the specimen treated by HFMI was reported to be lengthen between two and ten times depending on the weld configuration and the base material. Current study aims to investigate the influence of HFMI on the residual stresses field of a GMAW butt-weld joint of the HSLA steel S700MC 10 mm thick. For the numerical simulation of the HFMI-treatment, a suitable material hardening model was employed and stress relaxation during fatigue loading was taken into account. PIN was simulated as a discrete body in order to save computational time. Displacement-controlled simulations were carried out to estimate the local residual stress evolution considering the effect of combined isotropic-kinematic hardening law. Typical results are depicted and allow the correlation between experimental settings of the HFMI tool and the quantification of the residual stresses reduction in the weld area. Evaluation points out that HFMI can be used as a mitigation tool as it modifies residual stress fields radically and can play a vital role on the fatigue life extension of the weld studied.	en
heal.advisorName	Ζερβάκη, Άννα	el
heal.advisorName	Zervaki, Anna	en
heal.committeeMemberName	Ανυφαντής, Κωνσταντίνος	en
heal.committeeMemberName	Παπαδάκης, Γεώργιος	en
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Ναυπηγών Μηχανολόγων Μηχανικών. Τομέας Θαλάσσιων Κατασκευών. Εργαστήριο Ναυπηγικής Τεχνολογίας	el
heal.academicPublisherID	ntua
heal.fullTextAvailability	false