{"id":{"repo_id":"greece","oai_identifier":"oai:10442/0546"},"canonical_url":"https://search.dev.ndltd.org/etd/greece/oai:10442/0546","repository":{"repo_id":"greece","name":"Greek National Archive of PhD Theses","base_url":"https://phdtheses.ekt.gr/eadd_oai/request"},"display":{"title":"ΕΛΕΓΧΟΜΕΝΗ ΔΙΑΔΟΣΗ ΡΩΓΜΩΝ ΛΟΓΩ ΚΟΠΩΣΗΣ ΣΕ ΣΥΝΘΗΚΕΣ ΣΥΝΤΟΝΙΣΜΟΥ","abstract":"FATIGUE CRACK PROPAGATION IN VARIOUS RESONATING MEMBERS IS STUDIED. THE CRACK PROPAGATION RATE IS RELATED TO THE STRESS INTENSITY FACTOR OR THE STRAIN ENERGY DENSITY FACTOR DEPENDING ON THE KIND OF THE APPLIED LOADING. FOR THIS PURPOSE, THE WELL KNOWN EQUATIONS OF PARIS AND SIH ARE USED. THE DEPTH OF THE CRACK DETERMINES THE LOCAL STIFFNESS INTRODUCED BY THE CRACK, WHICH IN TURN INFLUENCES THE DYNAMIC RESPONSE OF THE MEMBER UNDER AN EXTERNAL EXCITATION OF CONSTANT AMPLITUDE AND FREQUENCY. AS THE CRACK PROPAGATES, INTRODUCES ADDITIONAL FLEXIBILITY TO THE SYSTEM . AS THE CRACK PROPAGATES, INTRODUCES ADDITIONAL FLEXIBILITY TO THE SYSTEM, WHICH GUIDES TO SHIFT AWAY FROM RESONANCE AND RESULTS IN SMALLER LOADING OF THE CRACKED SECTION. THIS CAUSES THE CRACK PROPAGATION RATE TO BE DRASTICALLY REDUCED AND, UNDER CERTAIN CIRCUMSTANCES, TO BECOME SMALLER THAN A THRESHOLD LEVEL, CHARACTERISTIC OF THE MATERIAL CONSIDERED. THIS PHENOMENON CAN BE INTERPRETED AS DYNAMIC CRACK ARREST. FOR STRUCTURAL MEMBERS AND IF THE MATERIAL DAMPING DOMINATES, THE LOSS COEFFICIENT IS PROVED TO BE THE MAIN FACTOR DETERMINING DECISIVELY THE CRACK PROPAGATION RATE AT THE INITIAL STAGES OF THE CRACK GROWTH.","abstract_html":"FATIGUE CRACK PROPAGATION IN VARIOUS RESONATING MEMBERS IS STUDIED. THE CRACK PROPAGATION RATE IS RELATED TO THE STRESS INTENSITY FACTOR OR THE STRAIN ENERGY DENSITY FACTOR DEPENDING ON THE KIND OF THE APPLIED LOADING. FOR THIS PURPOSE, THE WELL KNOWN EQUATIONS OF PARIS AND SIH ARE USED. THE DEPTH OF THE CRACK DETERMINES THE LOCAL STIFFNESS INTRODUCED BY THE CRACK, WHICH IN TURN INFLUENCES THE DYNAMIC RESPONSE OF THE MEMBER UNDER AN EXTERNAL EXCITATION OF CONSTANT AMPLITUDE AND FREQUENCY. AS THE CRACK PROPAGATES, INTRODUCES ADDITIONAL FLEXIBILITY TO THE SYSTEM . AS THE CRACK PROPAGATES, INTRODUCES ADDITIONAL FLEXIBILITY TO THE SYSTEM, WHICH GUIDES TO SHIFT AWAY FROM RESONANCE AND RESULTS IN SMALLER LOADING OF THE CRACKED SECTION. THIS CAUSES THE CRACK PROPAGATION RATE TO BE DRASTICALLY REDUCED AND, UNDER CERTAIN CIRCUMSTANCES, TO BECOME SMALLER THAN A THRESHOLD LEVEL, CHARACTERISTIC OF THE MATERIAL CONSIDERED. THIS PHENOMENON CAN BE INTERPRETED AS DYNAMIC CRACK ARREST. FOR STRUCTURAL MEMBERS AND IF THE MATERIAL DAMPING DOMINATES, THE LOSS COEFFICIENT IS PROVED TO BE THE MAIN FACTOR DETERMINING DECISIVELY THE CRACK PROPAGATION RATE AT THE INITIAL STAGES OF THE CRACK GROWTH.","abstract_has_math":false,"creators":["Δέντσορας, Αργύρης","Dentsoras, Argyris"],"institution":"University of Patras","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1987,"date_issued":"1987","date_published":"1987","updated_at":"2026-07-24T02:25:21Z","subjects":["Διάδοση ρωγμών","Κόπωση","Ρωγμή κόπωσης","ΣΥΝΤΕΛΕΣΤΗΣ ΑΠΟΣΒΕΣΗΣ ΥΛΙΚΟΥ","Συντονισμός","CRACK BECAUSE OF FATIGUE","Crack propagation","Fatigue","LOSS COEFFICIENT","Resonance","Επιστήμες Μηχανικού και Τεχνολογία","Επιστήμη Μηχανολόγου Μηχανικού","Engineering and Technology","Mechanical Engineering"],"languages":["gre"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["10.12681/eadd/0546"],"render_values":[{"text":"10.12681/eadd/0546","href":"https://doi.org/10.12681/eadd/0546","code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10442/hedi/0546","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Δέντσορας, Αργύρης","Dentsoras, Argyris"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["1987"]},{"key":"dc:publisher","label":"Institution","values":["University of Patras","Πανεπιστήμιο Πατρών"]},{"key":"dc:type","label":"Dc Type","values":["PhD Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Διάδοση ρωγμών","Κόπωση","Ρωγμή κόπωσης","ΣΥΝΤΕΛΕΣΤΗΣ ΑΠΟΣΒΕΣΗΣ ΥΛΙΚΟΥ","Συντονισμός","CRACK BECAUSE OF FATIGUE","Crack propagation","Fatigue","LOSS COEFFICIENT","Resonance","Επιστήμες Μηχανικού και Τεχνολογία","Επιστήμη Μηχανολόγου Μηχανικού","Engineering and Technology","Mechanical Engineering"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["gre"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["10.12681/eadd/0546","http://hdl.handle.net/10442/hedi/0546"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["FATIGUE CRACK PROPAGATION IN VARIOUS RESONATING MEMBERS IS STUDIED. THE CRACK PROPAGATION RATE IS RELATED TO THE STRESS INTENSITY FACTOR OR THE STRAIN ENERGY DENSITY FACTOR DEPENDING ON THE KIND OF THE APPLIED LOADING. FOR THIS PURPOSE, THE WELL KNOWN EQUATIONS OF PARIS AND SIH ARE USED. THE DEPTH OF THE CRACK DETERMINES THE LOCAL STIFFNESS INTRODUCED BY THE CRACK, WHICH IN TURN INFLUENCES THE DYNAMIC RESPONSE OF THE MEMBER UNDER AN EXTERNAL EXCITATION OF CONSTANT AMPLITUDE AND FREQUENCY. AS THE CRACK PROPAGATES, INTRODUCES ADDITIONAL FLEXIBILITY TO THE SYSTEM . AS THE CRACK PROPAGATES, INTRODUCES ADDITIONAL FLEXIBILITY TO THE SYSTEM, WHICH GUIDES TO SHIFT AWAY FROM RESONANCE AND RESULTS IN SMALLER LOADING OF THE CRACKED SECTION. THIS CAUSES THE CRACK PROPAGATION RATE TO BE DRASTICALLY REDUCED AND, UNDER CERTAIN CIRCUMSTANCES, TO BECOME SMALLER THAN A THRESHOLD LEVEL, CHARACTERISTIC OF THE MATERIAL CONSIDERED. THIS PHENOMENON CAN BE INTERPRETED AS DYNAMIC CRACK ARREST. FOR STRUCTURAL MEMBERS AND IF THE MATERIAL DAMPING DOMINATES, THE LOSS COEFFICIENT IS PROVED TO BE THE MAIN FACTOR DETERMINING DECISIVELY THE CRACK PROPAGATION RATE AT THE INITIAL STAGES OF THE CRACK GROWTH.","ΣΤΗΝ ΕΡΓΑΣΙΑ ΑΥΤΗ ΕΞΕΤΑΖΕΤΑΙ ΤΟ ΦΑΙΝΟΜΕΝΟ ΤΗΣ ΕΛΕΓΧΟΜΕΝΗΣ ΔΙΑΔΟΣΗΣ ΡΩΓΜΩΝ ΛΟΓΩ ΚΟΠΩΣΗΣ ΣΕ ΔΙΑΦΟΡΕΣ ΤΑΛΑΝΤΟΥΜΕΝΕΣ ΚΑΤΑΣΚΕΥΕΣ ΣΕ ΣΥΝΘΗΚΕΣ ΣΥΝΤΟΝΙΣΜΟΥ. ΣΕ ΤΑΛΑΝΤΟΥΜΕΝΑ ΣΥΣΤΗΜΑΤΑ ΣΥΝΕΧΟΥΣ 'Η ΚΑΤΑΝΕΜΗΜΕΝΗΣ ΜΑΖΑΣ, ΚΑΤΩ ΑΠΟ ΑΠΛΗ 'Η ΣΥΝΔΥΑΣΜΕΝΗ ΦΟΡΤΙΣΗ, ΕΦΑΡΜΟΖΟΝΤΑΙ ΟΙ ΓΝΩΣΤΕΣ ΣΧΕΣΕΙΣ ΤΩΝ PARIS ΚΑΙ SIH ΑΝΑΛΟΓΑ, ΠΟΥ ΣΧΕΤΙΖΟΥΝ ΤΟΝ ΡΥΘΜΟ ΔΙΑΔΟΣΗΣ ΜΙΑΣ ΡΩΓΜΗΣ ΜΕ ΤΗΝ ΜΕΤΑΒΟΛΗ ΤΗΣ ΤΙΜΗΣ ΤΟΥ ΠΕΔΙΟΥ ΜΕΤΑΒΟΛΗΣ ΤΟΥ ΣΥΝΤΕΛΕΣΤΗ ΕΝΤΑΣΗΣ ΤΑΣΗΣ 'Η ΤΟΥ ΣΥΝΤΕΛΕΣΤΗ ΠΥΚΝΟΤΗΤΑΣ ΕΝΕΡΓΕΙΑΣ ΠΑΡΑΜΟΡΦΩΣΗΣ. Σ'ΕΝΑ ΑΡΧΙΚΑ ΡΗΓΜΑΤΩΜΕΝΟ ΣΥΣΤΗΜΑ, ΚΑΠΟΙΑ ΑΠ'ΤΙΣ ΙΔΙΟΣΥΧΝΟΤΗΤΕΣ ΤΟΥ ΕΧΕΙ ΤΡΟΠΟΠΟΙΗΘΕΙ ΕΛΑΦΡΑ ΛΟΓΩ ΡΩΓΜΗΣ. ΜΕ ΔΕΔΟΜΕΝΟ ΤΟΝ ΣΥΝΤΟΝΙΣΜΟ, Η ΡΩΓΜΗ ΔΙΑΔΙΔΕΤΑΙ, ΑΛΛΑΖΟΥΝ ΤΑ ΕΛΑΣΤΙΚΑ ΧΑΡΑΚΤΗΡΙΣΤΙΚΑ ΤΟΥ ΣΥΣΤΗΜΑΤΟΣ. ΕΤΣΙ ΠΑΥΕΙ ΒΑΘΜΙΑΙΑ ΝΑ ΥΠΑΡΧΕΙ ΣΥΝΤΟΝΙΣΜΟΣ ΚΑΙ Ο ΕΛΑΤΤΩΜΕΝΟΣ ΡΥΘΜΟΣ ΔΙΑΔΟΣΗΣ ΜΠΟΡΕΙ ΝΑ ΓΙΝΕΙ ΜΙΚΡΟΤΕΡΟΣ ΑΠΟ ΜΙΑ ΟΡΙΑΚΗ ΤΙΜΗ, ΧΑΡΑΚΤΗΡΙΣΤΙΚΗ ΤΟΥ ΥΛΙΚΟΥ ΚΑΙ ΠΡΑΚΤΙΚΑ ΝΑ ΣΤΑΜΑΤΗΣΕΙ Η ΔΙΑΔΟΣΗ. ΤΟ ΦΑΙΝΟΜΕΝΟ ΟΝΟΜΑΖΕΤΑΙ ΔΥΝΑΜΙΚΗ ΣΥΛΛΗΨΗ ΤΗΣ ΡΩΓΜΗΣ. ΤΕΛΟΣ ΜΕ ΤΗΝ ΠΑΡΑΔΟΧΗ ΟΤΙ ΚΥΡΙΑΡΧΟΣ ΑΠΟΣΒΕΣΤΙΚΟΣ ΜΗΧΑΝΙΣΜΟΣ ΕΙΝΑΙ Η ΑΠΟΣΒΕΣΗ ΥΛΙΚΟΥ, ΑΠΟΔΕΙΚΝΥΕΤΑΙ ΟΤΙ Ο ΣΥΝΤΕΛΕΣΤΗΣ ΑΠΟΣΒΕΣΗΣ ΚΑΘΟΡΙΖΕΙ ΑΠΟΦΑΣΙΣΤΙΚΑ ΤΟΝ ΡΥΘΜΟ ΔΙΑΔΟΣΗΣ ΣΤΑ ΠΡΩΤΑ ΣΤΑΔΙΑ ΤΟΥ ΦΑΙΝΟΜΕΝΟΥ ΚΑΙ ΤΗΝ ΥΠΑΡΞΗ 'Η ΜΗ ΔΥΝΑΜΙΚΗΣ ΣΥΛΛΗΨΗΣ ΤΗΣ ΡΩΓΜΗΣ."]},{"key":"dc:title","label":"Title","values":["ΕΛΕΓΧΟΜΕΝΗ ΔΙΑΔΟΣΗ ΡΩΓΜΩΝ ΛΟΓΩ ΚΟΠΩΣΗΣ ΣΕ ΣΥΝΘΗΚΕΣ ΣΥΝΤΟΝΙΣΜΟΥ","RESONANCE CONTROLLED FATIGUE CRACK PROPAGATION"]}]}],"canonical_facts":{"dc:creator":["Δέντσορας, Αργύρης","Dentsoras, Argyris"],"dc:date":["1987"],"dc:description":["FATIGUE CRACK PROPAGATION IN VARIOUS RESONATING MEMBERS IS STUDIED. THE CRACK PROPAGATION RATE IS RELATED TO THE STRESS INTENSITY FACTOR OR THE STRAIN ENERGY DENSITY FACTOR DEPENDING ON THE KIND OF THE APPLIED LOADING. FOR THIS PURPOSE, THE WELL KNOWN EQUATIONS OF PARIS AND SIH ARE USED. THE DEPTH OF THE CRACK DETERMINES THE LOCAL STIFFNESS INTRODUCED BY THE CRACK, WHICH IN TURN INFLUENCES THE DYNAMIC RESPONSE OF THE MEMBER UNDER AN EXTERNAL EXCITATION OF CONSTANT AMPLITUDE AND FREQUENCY. AS THE CRACK PROPAGATES, INTRODUCES ADDITIONAL FLEXIBILITY TO THE SYSTEM . AS THE CRACK PROPAGATES, INTRODUCES ADDITIONAL FLEXIBILITY TO THE SYSTEM, WHICH GUIDES TO SHIFT AWAY FROM RESONANCE AND RESULTS IN SMALLER LOADING OF THE CRACKED SECTION. THIS CAUSES THE CRACK PROPAGATION RATE TO BE DRASTICALLY REDUCED AND, UNDER CERTAIN CIRCUMSTANCES, TO BECOME SMALLER THAN A THRESHOLD LEVEL, CHARACTERISTIC OF THE MATERIAL CONSIDERED. THIS PHENOMENON CAN BE INTERPRETED AS DYNAMIC CRACK ARREST. FOR STRUCTURAL MEMBERS AND IF THE MATERIAL DAMPING DOMINATES, THE LOSS COEFFICIENT IS PROVED TO BE THE MAIN FACTOR DETERMINING DECISIVELY THE CRACK PROPAGATION RATE AT THE INITIAL STAGES OF THE CRACK GROWTH.","ΣΤΗΝ ΕΡΓΑΣΙΑ ΑΥΤΗ ΕΞΕΤΑΖΕΤΑΙ ΤΟ ΦΑΙΝΟΜΕΝΟ ΤΗΣ ΕΛΕΓΧΟΜΕΝΗΣ ΔΙΑΔΟΣΗΣ ΡΩΓΜΩΝ ΛΟΓΩ ΚΟΠΩΣΗΣ ΣΕ ΔΙΑΦΟΡΕΣ ΤΑΛΑΝΤΟΥΜΕΝΕΣ ΚΑΤΑΣΚΕΥΕΣ ΣΕ ΣΥΝΘΗΚΕΣ ΣΥΝΤΟΝΙΣΜΟΥ. ΣΕ ΤΑΛΑΝΤΟΥΜΕΝΑ ΣΥΣΤΗΜΑΤΑ ΣΥΝΕΧΟΥΣ 'Η ΚΑΤΑΝΕΜΗΜΕΝΗΣ ΜΑΖΑΣ, ΚΑΤΩ ΑΠΟ ΑΠΛΗ 'Η ΣΥΝΔΥΑΣΜΕΝΗ ΦΟΡΤΙΣΗ, ΕΦΑΡΜΟΖΟΝΤΑΙ ΟΙ ΓΝΩΣΤΕΣ ΣΧΕΣΕΙΣ ΤΩΝ PARIS ΚΑΙ SIH ΑΝΑΛΟΓΑ, ΠΟΥ ΣΧΕΤΙΖΟΥΝ ΤΟΝ ΡΥΘΜΟ ΔΙΑΔΟΣΗΣ ΜΙΑΣ ΡΩΓΜΗΣ ΜΕ ΤΗΝ ΜΕΤΑΒΟΛΗ ΤΗΣ ΤΙΜΗΣ ΤΟΥ ΠΕΔΙΟΥ ΜΕΤΑΒΟΛΗΣ ΤΟΥ ΣΥΝΤΕΛΕΣΤΗ ΕΝΤΑΣΗΣ ΤΑΣΗΣ 'Η ΤΟΥ ΣΥΝΤΕΛΕΣΤΗ ΠΥΚΝΟΤΗΤΑΣ ΕΝΕΡΓΕΙΑΣ ΠΑΡΑΜΟΡΦΩΣΗΣ. Σ'ΕΝΑ ΑΡΧΙΚΑ ΡΗΓΜΑΤΩΜΕΝΟ ΣΥΣΤΗΜΑ, ΚΑΠΟΙΑ ΑΠ'ΤΙΣ ΙΔΙΟΣΥΧΝΟΤΗΤΕΣ ΤΟΥ ΕΧΕΙ ΤΡΟΠΟΠΟΙΗΘΕΙ ΕΛΑΦΡΑ ΛΟΓΩ ΡΩΓΜΗΣ. ΜΕ ΔΕΔΟΜΕΝΟ ΤΟΝ ΣΥΝΤΟΝΙΣΜΟ, Η ΡΩΓΜΗ ΔΙΑΔΙΔΕΤΑΙ, ΑΛΛΑΖΟΥΝ ΤΑ ΕΛΑΣΤΙΚΑ ΧΑΡΑΚΤΗΡΙΣΤΙΚΑ ΤΟΥ ΣΥΣΤΗΜΑΤΟΣ. ΕΤΣΙ ΠΑΥΕΙ ΒΑΘΜΙΑΙΑ ΝΑ ΥΠΑΡΧΕΙ ΣΥΝΤΟΝΙΣΜΟΣ ΚΑΙ Ο ΕΛΑΤΤΩΜΕΝΟΣ ΡΥΘΜΟΣ ΔΙΑΔΟΣΗΣ ΜΠΟΡΕΙ ΝΑ ΓΙΝΕΙ ΜΙΚΡΟΤΕΡΟΣ ΑΠΟ ΜΙΑ ΟΡΙΑΚΗ ΤΙΜΗ, ΧΑΡΑΚΤΗΡΙΣΤΙΚΗ ΤΟΥ ΥΛΙΚΟΥ ΚΑΙ ΠΡΑΚΤΙΚΑ ΝΑ ΣΤΑΜΑΤΗΣΕΙ Η ΔΙΑΔΟΣΗ. ΤΟ ΦΑΙΝΟΜΕΝΟ ΟΝΟΜΑΖΕΤΑΙ ΔΥΝΑΜΙΚΗ ΣΥΛΛΗΨΗ ΤΗΣ ΡΩΓΜΗΣ. ΤΕΛΟΣ ΜΕ ΤΗΝ ΠΑΡΑΔΟΧΗ ΟΤΙ ΚΥΡΙΑΡΧΟΣ ΑΠΟΣΒΕΣΤΙΚΟΣ ΜΗΧΑΝΙΣΜΟΣ ΕΙΝΑΙ Η ΑΠΟΣΒΕΣΗ ΥΛΙΚΟΥ, ΑΠΟΔΕΙΚΝΥΕΤΑΙ ΟΤΙ Ο ΣΥΝΤΕΛΕΣΤΗΣ ΑΠΟΣΒΕΣΗΣ ΚΑΘΟΡΙΖΕΙ ΑΠΟΦΑΣΙΣΤΙΚΑ ΤΟΝ ΡΥΘΜΟ ΔΙΑΔΟΣΗΣ ΣΤΑ ΠΡΩΤΑ ΣΤΑΔΙΑ ΤΟΥ ΦΑΙΝΟΜΕΝΟΥ ΚΑΙ ΤΗΝ ΥΠΑΡΞΗ 'Η ΜΗ ΔΥΝΑΜΙΚΗΣ ΣΥΛΛΗΨΗΣ ΤΗΣ ΡΩΓΜΗΣ."],"dc:identifier":["10.12681/eadd/0546","http://hdl.handle.net/10442/hedi/0546"],"dc:language":["gre"],"dc:publisher":["University of Patras","Πανεπιστήμιο Πατρών"],"dc:subject":["Διάδοση ρωγμών","Κόπωση","Ρωγμή κόπωσης","ΣΥΝΤΕΛΕΣΤΗΣ ΑΠΟΣΒΕΣΗΣ ΥΛΙΚΟΥ","Συντονισμός","CRACK BECAUSE OF FATIGUE","Crack propagation","Fatigue","LOSS COEFFICIENT","Resonance","Επιστήμες Μηχανικού και Τεχνολογία","Επιστήμη Μηχανολόγου Μηχανικού","Engineering and Technology","Mechanical Engineering"],"dc:title":["ΕΛΕΓΧΟΜΕΝΗ ΔΙΑΔΟΣΗ ΡΩΓΜΩΝ ΛΟΓΩ ΚΟΠΩΣΗΣ ΣΕ ΣΥΝΘΗΚΕΣ ΣΥΝΤΟΝΙΣΜΟΥ","RESONANCE CONTROLLED FATIGUE CRACK PROPAGATION"],"dc:type":["PhD Thesis"]},"updated_at":"2026-07-24T02:25:21Z"}