Seminar
MECHANICS OF MACHINES AND MECHANISMS - MODELS AND MATHEMATICAL METHODS

 

PROGRAM

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Plan rada Seminara Mehanika mašina i mehanizama - modeli i matematičke metode za NOVEMBAR 2021.

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UTORAK, 09.11.2021. u 18:00, Live stream
Bojan Međo, Marko Rakin, University of Belgrade, Faculty of Technology and Metallurgy, Serbia
Nenad Gubeljak, University of Maribor, Faculty of Mechanical Engineering, Slovenia
DETERMINATION OF FRACTURE PROPERTIES OF PIPELINE MATERIALS BY APPLICATION OF NON-STANDARD RING SPECIMENS
Determination of fracture properties of pipeline materials is an important issue in all industries which utilize the pressurized equipment. Generally, resistance to fracture of metallic structures is defined by standard testing procedures; one of the most widely used ones is ASTM E1820 - Standard Test Method for Measurement of Fracture Toughness. However, when these procedures are applied to thin-walled structures, such as pressure vessels and pipelines, the most pronounced problem is the fact that they require plane strain conditions in the specimen, i.e. sufficient thickness, in order to get a reliable result.
In the literature, many authors have dealt with this problem by introducing some non-standard specimen geometries and more or less complex testing procedures. An overview of the proposed specimens/procedures, as well as their advantages and drawbacks, will be given. The results obtained by the authors on recently introduced Pipe Ring Notched Bend (PRNB) specimens will be covered in more detail. These results include the ductile fracture analysis of ring specimens cut from the seamless and seam (welded) steel pipes. Finally, a new type of specimen - Pipe Ring Notched Tensile (PRNT) specimen, which is introduced and is currently being developed, will be described and the results obtained so far will be shown. The procedure for calculation of fracture mechanics parameters will be presented, with special emphasis on the influence of the loading type change (tension instead of bending).

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UTORAK, 23.11.2021. u 17:00, Live stream
Andjelka Hedrih, Katica (Stevanović) Hedrih, Mathematical Institute of the Serbian Academy of Sciences and Arts, Belgrade, Serbia
OSCILLATIONS AND STABILITY OF A COMPLEX CANTILEVER AND ITS POTENTIAL APPLICATIONS
Cantilevers have wide usage in industry and building constructions, in biosensors, AFM tips. The geometrical form of cantilever influences its stability. The model of the complex cantilever with attached masses is proposed and described. The complexity is in its geometrical form and different distribution of masses. The main body of the cantilever has ideally elastic properties. Other elements are rigidly connected to the man part of the cantilever. The complex cantilever can oscillate in two orthogonal planes. We investigate free and forced oscillation of this hybrid complex structure using the system of coupled differential equations. Specific geometrical parameters like angles and pattern of mass distribution influence stability of oscillatory modes of this complex cantilever. The problem of stability and instability of a complex cantilever will be analysed trough amplitude-frequency curves. Different geometrical designed in industry and bioscience will be discussed.

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Obavezno je nošenje maski i održavanje distance. Broj prisutnih na predavanju ograničen na najviše 10 (uključujući i predavača).

Seminar Mehanika mašina i mehanizama - modeli i matematičke metode započeo je sa radom u junu 2018.god. Seminar se održava do dva puta mesečno, utorkom u periodu od 17.00 - 19.00 u Matematičkom institutu SANU.

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