[institut] Plan rada Odeljenja za mehaniku za decembar 2017.

[Odeljenje za mehaniku]

Poštovane koleginice i kolege,

u nastavku i prilogu ove poruke priložen je plan predavanja Odeljenja za 
mehaniku MISANU za decembar 2017.

Ukoliko ste u mogućnosti molimo vas da priloženi .pdf odštampate i izložite na 
oglasnim tablama vaših institucija.

S poštovanjem,
Tatjana Jakšić Krüger

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- PLAN RADA ZA DECEMBAR 2017. -
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Sreda, 6. decembar, 18:00

Si Mohamed Sah, Danish Technical University (DTU)

ASSESSING BOLTED JOINTS TIGHTNESS WITH MEASURED NATURAL FREQUENCY

Rezime: Structural health monitoring techniques based on vibration measurements 
have been receiving large attention in the last decades, in particular 
techniques used for estimating bolted joints tightness and detecting loosened 
bolts. Due to the exposure of bolted joints to external forces, the bolts may 
loosen and therefore affect the healthy functioning of the bolted structure. In 
this work, a technique is proposed to assess the level of bolt tightness and to 
quantify the tension based on the measured natural frequencies. An experiment 
is performed on two structure specimen where each one is clamped with a bolt. 
The excited natural frequencies are recorded as the bolts are gradually 
tightened. The measured frequencies trends were described by a one dimensional 
beam model with elastic supports. The sensitivity of the measured transverse 
frequency showed the reliability of this frequency-based technique in assessing 
bolt tightness. This technique can also quantify the bolt tension using the 
analytical model, which gave an excellent agreement with the experimental data 
for high bolt tension.

***

Sreda, 13. decembar, 18:00

Dragomir Zeković, Mašinski fakultet, Beograd

DINAMIKA MEHANIČKIH SISTEMA SA NELINEARNIM NEHOLONOMNIM VEZAMA - III ANALIZA 
KRETANjA

Rezime: Analizira se kretanje neholonomnih mehaničkih sistema, sastavljenih od 
dve materijalne tačke kojima se nameću različita nelinearna ograničenja na 
brzine tih tačaka – paralelnost brzine, jednakost intenziteta brzina i 
upravnost brzina. Za takve sisteme se analiziraju: jednačine veza, reakcije 
veza tj. način variranja takvih veza, trajektorije tačaka sistema, linearni 
integrali po generalisanim brzinama tj. ciklične koordinata. Na ovim modelima 
se jasno pokazuje da u slučaju nelinearnih neholonomnih veza Hamiltonovo 
dejstvo u opštem slučaju nema stacionarnu vrednost. Na kraju su izvedene 
jednačine brahistohronog kretanja opisanih sistema i određene brahistohrone 
određenih tačaka.

***

Sreda, 20. decembar, 18:00

Ván Péter, Institute for Particle and Nuclear Physics, Wigner Research Centre 
for Physics

INTERNAL VARIABLES IN THERMOMECHANICS: A SIMPLE APPROACH TO MEMORY AND WEAK 
NONLOCALITY

Rezime: The role of internal variables is to improve the performance and extend 
the validity of theories of mechanics and thermodynamics. However, their 
mechanical and thermodynamical appearance, the related theoretical structures 
are different and seemingly incompatible. In the presentation I show a unified 
treatment and  shortly survey the  various experimental and theoretical efforts 
of our group to develop and validate the theory.

***

Sreda, 27. decembar, 18:00

Vladimir Dragović, Matematički institut SANU
(naslov i rezime predavanja će biti naknadno dostavljeni)

___________________________
Najavljena predavanja će se održati u sali 301f, III sprat, Matematički 
institut, Knez Mihailova 36. Predavanja su namenjena širokom krugu slušalaca, 
uključujući studente redovnih i doktorskih studija.

Upravnik Odeljenja za mehaniku MISANU:
dr Božidar Jovanović
http://www.mi.sanu.ac.rs/novi_sajt/research/mechcoll.php
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