Procena integriteta zavarenih konstrukcija projektovanih sa smanjenim stepenom sigurnosti
Integrity assessment of welded structures designed with reduced safety
Author
Jeremić, LazarMentor
Sedmak, AleksandarCommittee members
Radaković, ZoranPopović, Olivera
Gnjatović, Nebojša
Sedmak, Simon
Metadata
Show full item recordAbstract
Predmet ove doktorske disertacije je istraživanje ponašanja zavarenih konstrukcija sa
smanjenim stepenom sigurnosti prema krtom lomu i otpornost na prsline u cilju ocene njenog
integriteta i veka. U tom slučaju posebna pažnja se posvećuje mestima koncentracije napona, jer se
krti lomovi ovih konstrukcija po pravilu događaju upravo na takvim mestima. Radi detaljnog
proučavanja nakstanka i rasta prsline, neophodna je primena principa mehanike loma, jer klasični
pristup konstruisanju (projektovanju) preko faktora koncentracije napona i čvrstoće u tom slučaju
nije dovoljan. Primenom parametra mehanike loma, kao što je faktor inteziteta napona, čiji opseg
definiše brzinu rasta prline, a čija kritična veličina (žilavost loma) određuje kritičnu dužinu prsline.
Time se obezbeđuje pouzdana procena integriteta konstrukcije (ako se dokaže da je faktor
intenziteta napona manji od žilavosti loma), odnosno procena veka konstrukcije (primenom zakona
mehanike loma na izračuvavanje krritičnih parametar...a za poznatu ili pretpostavljenu početnu
dužinu prsline, njenu kritičnu vrednost, kao i izračunati opseg faktora intenzitata napona).
Konzervativni pristup u svim koracima ove procedure obezbeđuje pouzdanu eksploataciju
konstrukcije sa smanjenim stepenom sigurnosti.
The subject of this doctoral dissertation is the research of the behavior of welded structures
with a reduced degree of safety on brittle fracture and crack resistance in order to assess its integrity
and age. In this case, special attention is paid to the stress concentration points, since the fractures
of these structures tend to occur exactly in such places. For the detailed study of the crack and
growth of the crack, it is necessary to apply the principle of fracture mechanics, since the classical
approach to design (design) through the factor of stress concentration and strength is not sufficient
in that case. Using the fracture mechanics parameter, such as the voltage intensity factor, whose
range defines the rate of crack growth, and whose critical size (fracture toughness) determines the
critical crack length. This ensures a reliable assessment of the integrity of the structure (if it is
proven that the stress intensity factor is less than the tensile strength of the fracture),... or the
assessment of the century of construction (by applying laws of fracture mechanics to calculate
critical parameters for known or assumed initial crack length, its critical value, as well as calculate
the range voltage intensities factor). A conservative approach in all steps of this procedure ensures
reliable exploitation of a structure with a reduced degree of safety
Faculty:
Универзитет у Београду, Машински факултетDate:
21-12-2020Projects:
- Developed new methods for diagnosis and examination mechanical structures (RS-MESTD-Technological Development (TD or TR)-35040)