Συντάχθηκε 27-10-2015 08:12
από Dorothea Fragomichelaki
Email συντάκτη: dfragomichelaki<στο>tuc.gr
Ενημερώθηκε:
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Ιδιότητα: υπάλληλος ΜΠΔ.
ΠΟΛΥΤΕΧΝΕΙΟ ΚΡΗΤΗΣ
ΣΧΟΛΗ ΜΗΧΑΝΙΚΩΝ ΠΑΡΑΓΩΓΗΣ ΚΑΙ ΔΙΟΙΚΗΣΗΣ
ΠΑΡΟΥΣΙΑΣΗ ΔΙΔΑΚΤΟΡΙΚΗΣ ΔΙΑΤΡΙΒΗΣ
κου Ν. Καμινάκη
με θέμα
"Topology optimization of polymorphic structures and mechanisms using global and multicriteria optimization"
Πέμπτη 29 Οκτωβρίου 2015, 12.00 μ
Αίθουσα διαλέξεων Σχολής ΜΠΔ (Δ3 004),Πολυτεχνειούπολη
ΕΞΕΤΑΣΤΙΚΗ ΕΠΙΤΡΟΠΗ
1. Σταυρουλάκης Ε. Γεώργιος. (επιβλέπων)
2. Μαρινάκης Ιωάννης, Επικ. Καθ. Π.Κ., μέλος τριμελούς
3. Παπαλάμπρος Παναγιώτης, Καθ. Michigan University, U.S.A., μέλος τριμελούς
4. Μπιλάλης Νικόλαος, Καθ. Π.Κ.,
5. Τσομπανάκης Ιωάννης, Αν. Καθ. Π.Κ.,
6. Λαγαρός Νικόλαος, Επικ. Καθ. Ε.Μ.Π.,
7. Μυστακίδης Ευριπίδης, Καθ. Πανεπιστημίου Θεσσαλίας
Summary
Topology optimization solves the basic engineering design problem of distributing a limited amount of material in a design space in order to form a structure or a mechanism that works in an optimal way. One of the most interesting applications is the synthesis of compliant mechanisms. A compliant mechanism is a flexible monolithic structure that transforms an external load to motion along a specific direction and the same time is stiff enough to bear with the applied forces.
Multi-purpose compliant mechanisms are structures with all the above features that are able to deliver two or more different motions depending on the applied load case.The majority of materials in nature when stretched in one direction, they get thinner and vice versa. The opposite effect take place in auxetic materials. Auxetic materials are artificial microstructures with properties that may not be found in nature. Their mechanical properties are defined by their structure rather than their composition. The feature that describes them as auxetic is the negative Poisson’s ratio. This auxetic behavior occurs due to their specific internal structure and the way it deforms when the sample is uniaxially loaded. The design of auxetic materials can follow similar techniques to the compliant mechanism and is presented as application.
Topology optimization is used as a conceptual design tool for compliant mechanisms and auxetical materilas. In anycase several multi-objective topology optimization problems are first formulated. From numerical experiments it was noticed that when topology optimization starts from initial random material distributions, the resulted structures are different, meaning that local minima arise. Therefore, a hybrid algorithm utilizing the advantages of global optimization techniques, is proposed. The hybrid scheme uses topology optimization as the evaluation tool of the previously mentioned global optimization algorithms.
