TY  - JOUR
AU  - Bakić, Ramo
AU  - Milović, Ljubica
AU  - Jovičić, Radomir
AU  - Sedmak, Stojan
PY  - 2013
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2295
AB  - According to the Pressure Equipment Directive (PED 97/23/EC) a new produced storage tank can be accepted on the market only if the required quality is proved. In this way the structural integrity might be at the requested level. However, it is not possible to apply all rules and standards for the quality during service and after performed repairs that are necessary to sustain the structural integrity of the storage tank. Storage tanks of steel are produced in general as cylindrical or spherical, and individual segments are joined by welding. Welded joints are prone to crack occurrence, and for that they are critical locations for safety and structural integrity. According to standard EN ISO 5817 cracks are not acceptable defects in welded structures, and detected cracks have to be removed. The applicability of quality assurance approach to repaired pressure equipment is analyzed and discussed in this paper. In the first case welded joints in spherical storage tanks produced of normalized high strength steel (460 MPa yield stress) microalloyed with vanadium are analyzed, considering repair and structural integrity assessment. In the second case, dissimilar welded joints of structural and stainless steel are examined.
AB  - Prema Direktivi za opremu pod pritiskom (PED 97/23/ EC) novo proizvedeni rezervoari se mogu prihvatiti za tržište samo ako je zahtevani kvalitet i dokazan. Na taj način integritet konstrukcije može biti na zahtevanom nivou. Ipak nije moguće sprovesti sva pravila i standarde za kvalitet tokom eksploatacije i posle izvedenih popravki, potrebnih da se održi integritet konstrukcije rezervoara. Rezervoari od čelika se uglavnom proizvode kao cilindrični ili sferni, na kojima su pojedinačni segmenti spojeni zavarivanjem. Zavareni spojevi su skloni pojavi prslina, i zbog toga su oni kritična mesta za sigurnost i integritet konstrukcije. Prema standardu EN ISO 5817 prsline nisu dopuštene greške na zavarenim konstrukcijama, i otkrivene prsline treba da se eliminišu. Primenljivost pristupa osiguranja kvaliteta na popravljenu opremu pod pritiskom je u ovom radu analizirana i diskutovana. U prvom primeru su analizirani sferni rezervoari izrađeni od normalizovanog čelika visoke čvrstoće (napon tečenja 460 MPa) mikrolegiranog vanadijumom, razmatranjem popravke i ocene integriteta konstrukcije. U drugom primeru su ispitivani raznorodni zavareni spojevi konstrukcijskog i nerđajućeg čelika.
PB  - Society for Structural Integrity and Life, Institute for Material Testing
T2  - Integritet i vek konstrukcija
T1  - Quality assurance of storage tanks after in-service crack repairs
T1  - Osiguranje kvaliteta rezervoara u eksploataciji posle popravke prslina
EP  - 74
IS  - 1
SP  - 63
VL  - 13
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2295
ER  - 

@article{
author = "Bakić, Ramo and Milović, Ljubica and Jovičić, Radomir and Sedmak, Stojan",
year = "2013",
abstract = "According to the Pressure Equipment Directive (PED 97/23/EC) a new produced storage tank can be accepted on the market only if the required quality is proved. In this way the structural integrity might be at the requested level. However, it is not possible to apply all rules and standards for the quality during service and after performed repairs that are necessary to sustain the structural integrity of the storage tank. Storage tanks of steel are produced in general as cylindrical or spherical, and individual segments are joined by welding. Welded joints are prone to crack occurrence, and for that they are critical locations for safety and structural integrity. According to standard EN ISO 5817 cracks are not acceptable defects in welded structures, and detected cracks have to be removed. The applicability of quality assurance approach to repaired pressure equipment is analyzed and discussed in this paper. In the first case welded joints in spherical storage tanks produced of normalized high strength steel (460 MPa yield stress) microalloyed with vanadium are analyzed, considering repair and structural integrity assessment. In the second case, dissimilar welded joints of structural and stainless steel are examined., Prema Direktivi za opremu pod pritiskom (PED 97/23/ EC) novo proizvedeni rezervoari se mogu prihvatiti za tržište samo ako je zahtevani kvalitet i dokazan. Na taj način integritet konstrukcije može biti na zahtevanom nivou. Ipak nije moguće sprovesti sva pravila i standarde za kvalitet tokom eksploatacije i posle izvedenih popravki, potrebnih da se održi integritet konstrukcije rezervoara. Rezervoari od čelika se uglavnom proizvode kao cilindrični ili sferni, na kojima su pojedinačni segmenti spojeni zavarivanjem. Zavareni spojevi su skloni pojavi prslina, i zbog toga su oni kritična mesta za sigurnost i integritet konstrukcije. Prema standardu EN ISO 5817 prsline nisu dopuštene greške na zavarenim konstrukcijama, i otkrivene prsline treba da se eliminišu. Primenljivost pristupa osiguranja kvaliteta na popravljenu opremu pod pritiskom je u ovom radu analizirana i diskutovana. U prvom primeru su analizirani sferni rezervoari izrađeni od normalizovanog čelika visoke čvrstoće (napon tečenja 460 MPa) mikrolegiranog vanadijumom, razmatranjem popravke i ocene integriteta konstrukcije. U drugom primeru su ispitivani raznorodni zavareni spojevi konstrukcijskog i nerđajućeg čelika.",
publisher = "Society for Structural Integrity and Life, Institute for Material Testing",
journal = "Integritet i vek konstrukcija",
title = "Quality assurance of storage tanks after in-service crack repairs, Osiguranje kvaliteta rezervoara u eksploataciji posle popravke prslina",
pages = "74-63",
number = "1",
volume = "13",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2295"
}

Bakić, R., Milović, L., Jovičić, R.,& Sedmak, S.. (2013). Quality assurance of storage tanks after in-service crack repairs. in Integritet i vek konstrukcija
Society for Structural Integrity and Life, Institute for Material Testing., 13(1), 63-74.
https://hdl.handle.net/21.15107/rcub_technorep_2295

Bakić R, Milović L, Jovičić R, Sedmak S. Quality assurance of storage tanks after in-service crack repairs. in Integritet i vek konstrukcija. 2013;13(1):63-74.
https://hdl.handle.net/21.15107/rcub_technorep_2295 .

Bakić, Ramo, Milović, Ljubica, Jovičić, Radomir, Sedmak, Stojan, "Quality assurance of storage tanks after in-service crack repairs" in Integritet i vek konstrukcija, 13, no. 1 (2013):63-74,
https://hdl.handle.net/21.15107/rcub_technorep_2295 .

TY  - JOUR
AU  - Milović, Ljubica
AU  - Bulatović, Srđan
AU  - Aleksić, Vujadin
AU  - Radaković, Zoran
AU  - Marković, Svetislav
AU  - Sedmak, Stojan
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2050
AB  - From a fracture mechanics point of view on welded joints, it is assumed that the welded joint is pre-cracked such as that the fatigue life of the pre-cracked structure is then determined by the period of crack growth under variable load. Experimental data obtained by testing provide a substantial basis for a better understanding and an explanation of the phenomenon of material fatigue. Low cycle fatigue (LCF) occurs during the process of charging and discharging of reactors, pressure vessels and pipelines; the fatigue can be accelerated by an additional negative effect of temperature variation and the aggressive effect of the media contained inside the vessel, and during the exploitation of the equipment in the processing industry. In the present paper the results are presented of J-integral measurements at LCF of a low-alloyed high strength steel (HSLA) weld metal used in the submerged arc welding process in the manufacture of pressure vessels.
AB  - U zavarenim spojevima, sa gledišta mehanike loma, se pretpostavlja prisustvo prslina, gde se onda vek s obzirom na zamor takvih konstrukcija sa prslinama procenjuje vremenom rasta prsline pod promenljivim opterećenjem. Eksperimentalni podaci dobijeni ispitivanjem pružaju značajnu osnovu za bolje razumevanje i objašnjenje fenomena zamora materijala. Niskociklični zamor (LCF) se javlja u procesu punjenja i pražnjenja reaktora, posuda pod pritiskom i cevovoda; proces zamora može ubrzati dodatni negativan efekat promene temperature i efekat agresivne sredine sadržane u posudi, kao i tokom perioda eksploatacije opreme u procesnoj industriji. U ovom radu prikazani su rezultati merenja J integrala pri niskocikličnom zamoru (LCF) metala šava niskolegiranog čelika povišene čvrstoće (HSLA), koji se koristi u proizvodnji posuda pod pritiskom postupkom zavarivanja pod praškom.
PB  - Society for Structural Integrity and Life, Institute for Material Testing
T2  - Integritet i vek konstrukcija
T1  - Assessment of the behaviour of fatigue loaded HSLA steel welded joint by applying fracture mechanics parameters
T1  - Procena ponašanja zavarenog spoja HSLA čelika opterećenog na zamor primenom parametara mehanike loma
EP  - 179
IS  - 3
SP  - 175
VL  - 12
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2050
ER  - 

@article{
author = "Milović, Ljubica and Bulatović, Srđan and Aleksić, Vujadin and Radaković, Zoran and Marković, Svetislav and Sedmak, Stojan",
year = "2012",
abstract = "From a fracture mechanics point of view on welded joints, it is assumed that the welded joint is pre-cracked such as that the fatigue life of the pre-cracked structure is then determined by the period of crack growth under variable load. Experimental data obtained by testing provide a substantial basis for a better understanding and an explanation of the phenomenon of material fatigue. Low cycle fatigue (LCF) occurs during the process of charging and discharging of reactors, pressure vessels and pipelines; the fatigue can be accelerated by an additional negative effect of temperature variation and the aggressive effect of the media contained inside the vessel, and during the exploitation of the equipment in the processing industry. In the present paper the results are presented of J-integral measurements at LCF of a low-alloyed high strength steel (HSLA) weld metal used in the submerged arc welding process in the manufacture of pressure vessels., U zavarenim spojevima, sa gledišta mehanike loma, se pretpostavlja prisustvo prslina, gde se onda vek s obzirom na zamor takvih konstrukcija sa prslinama procenjuje vremenom rasta prsline pod promenljivim opterećenjem. Eksperimentalni podaci dobijeni ispitivanjem pružaju značajnu osnovu za bolje razumevanje i objašnjenje fenomena zamora materijala. Niskociklični zamor (LCF) se javlja u procesu punjenja i pražnjenja reaktora, posuda pod pritiskom i cevovoda; proces zamora može ubrzati dodatni negativan efekat promene temperature i efekat agresivne sredine sadržane u posudi, kao i tokom perioda eksploatacije opreme u procesnoj industriji. U ovom radu prikazani su rezultati merenja J integrala pri niskocikličnom zamoru (LCF) metala šava niskolegiranog čelika povišene čvrstoće (HSLA), koji se koristi u proizvodnji posuda pod pritiskom postupkom zavarivanja pod praškom.",
publisher = "Society for Structural Integrity and Life, Institute for Material Testing",
journal = "Integritet i vek konstrukcija",
title = "Assessment of the behaviour of fatigue loaded HSLA steel welded joint by applying fracture mechanics parameters, Procena ponašanja zavarenog spoja HSLA čelika opterećenog na zamor primenom parametara mehanike loma",
pages = "179-175",
number = "3",
volume = "12",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2050"
}

Milović, L., Bulatović, S., Aleksić, V., Radaković, Z., Marković, S.,& Sedmak, S.. (2012). Assessment of the behaviour of fatigue loaded HSLA steel welded joint by applying fracture mechanics parameters. in Integritet i vek konstrukcija
Society for Structural Integrity and Life, Institute for Material Testing., 12(3), 175-179.
https://hdl.handle.net/21.15107/rcub_technorep_2050

Milović L, Bulatović S, Aleksić V, Radaković Z, Marković S, Sedmak S. Assessment of the behaviour of fatigue loaded HSLA steel welded joint by applying fracture mechanics parameters. in Integritet i vek konstrukcija. 2012;12(3):175-179.
https://hdl.handle.net/21.15107/rcub_technorep_2050 .

Milović, Ljubica, Bulatović, Srđan, Aleksić, Vujadin, Radaković, Zoran, Marković, Svetislav, Sedmak, Stojan, "Assessment of the behaviour of fatigue loaded HSLA steel welded joint by applying fracture mechanics parameters" in Integritet i vek konstrukcija, 12, no. 3 (2012):175-179,
https://hdl.handle.net/21.15107/rcub_technorep_2050 .

TY  - JOUR
AU  - Sedmak, Stojan
AU  - Radaković, Zoran
AU  - Milović, Ljubica
AU  - Svetel, Igor
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2048
AB  - To avoid unexpected and frequent serious failures of objects and equipment in service, and save their structural integrity, proper experimental and theoretical analyses are required, that are supported by modeling and numerical analysis. Structural failures in service have been experienced and can not be neglected. The developed procedures, based on fracture mechanics, enable to predict behaviour of a crack in a fracture process and to evaluate the safety and reliability of a structure under the applied loading in an operating environment. Regarding the significance of structural integrity, objects are classified into three groups. In the first group are objects made of stone, not sensitive to cracking, as are the preserved monuments of the ancient era. The second group includes objects prone to fracture from cracks: in this case structural integrity assessment is a requirement in order to prevent failure. In the third group are modern engineering achievements as are very large buildings (e.g. Burj Khalifa), and nano-sized objects. They both require, involving new aspects, the consideration of functionality and reliability, in addition to safety. Several examples are presented here and discussed for each group.
AB  - Da bi se izbegli neočekivani i često ozbiljni otkazi u radu objekata i opreme i sačuvao integritet konstrukcija potrebne su odgovarajuće eksperimentalne i teorijske analize, podržane modeliranjem i numeričkom analizom. Mogućnost otkaza konstrukcije u radu se ne može zanemariti, jer se oni u praksi javljaju. Postupci, razvijeni na osnovu mehanike loma, omogućavaju da se predvidi ponašanje prsline u procesu loma i da se oceni sigurnost i pouzdanost konstrukcije pri opterećenju u radnim uslovima. Objekti su podeljeni u tri grupe s obzirom na značaj integriteta konstrukcije. U prvoj grupi su objekti, uglavnom izrađeni od kamena, koji nisu osetljivi na prsline, kao što su očuvani arheološki spomenici. Druga grupa uključuje konstrukcije sklone razvoju loma usled prslina: za njih se zahteva ocena integriteta da bi se sprečio otkaz. U trećoj grupi su nova tehnička dostignuća, kao što su velike građevine (na primer Burdž Kalifa) i objekti nano veličina. Zbog toga što se u oba slučaja unose novi aspekti, i objekti velikih i vrlo malih dimenzija zahtevaju da se, sem sigurnosti, razmotre funkcionalnost i pouzdanost. Za svaku grupu je nekoliko primera prikazano i diskutovano.
PB  - Society for Structural Integrity and Life, Institute for Material Testing
T2  - Integritet i vek konstrukcija
T1  - Significance and applicability of structural integrity assessment
T1  - Značaj i primenljivost ocene integriteta konstrukcija
EP  - 30
IS  - 1
SP  - 3
VL  - 12
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2048
ER  - 

@article{
author = "Sedmak, Stojan and Radaković, Zoran and Milović, Ljubica and Svetel, Igor",
year = "2012",
abstract = "To avoid unexpected and frequent serious failures of objects and equipment in service, and save their structural integrity, proper experimental and theoretical analyses are required, that are supported by modeling and numerical analysis. Structural failures in service have been experienced and can not be neglected. The developed procedures, based on fracture mechanics, enable to predict behaviour of a crack in a fracture process and to evaluate the safety and reliability of a structure under the applied loading in an operating environment. Regarding the significance of structural integrity, objects are classified into three groups. In the first group are objects made of stone, not sensitive to cracking, as are the preserved monuments of the ancient era. The second group includes objects prone to fracture from cracks: in this case structural integrity assessment is a requirement in order to prevent failure. In the third group are modern engineering achievements as are very large buildings (e.g. Burj Khalifa), and nano-sized objects. They both require, involving new aspects, the consideration of functionality and reliability, in addition to safety. Several examples are presented here and discussed for each group., Da bi se izbegli neočekivani i često ozbiljni otkazi u radu objekata i opreme i sačuvao integritet konstrukcija potrebne su odgovarajuće eksperimentalne i teorijske analize, podržane modeliranjem i numeričkom analizom. Mogućnost otkaza konstrukcije u radu se ne može zanemariti, jer se oni u praksi javljaju. Postupci, razvijeni na osnovu mehanike loma, omogućavaju da se predvidi ponašanje prsline u procesu loma i da se oceni sigurnost i pouzdanost konstrukcije pri opterećenju u radnim uslovima. Objekti su podeljeni u tri grupe s obzirom na značaj integriteta konstrukcije. U prvoj grupi su objekti, uglavnom izrađeni od kamena, koji nisu osetljivi na prsline, kao što su očuvani arheološki spomenici. Druga grupa uključuje konstrukcije sklone razvoju loma usled prslina: za njih se zahteva ocena integriteta da bi se sprečio otkaz. U trećoj grupi su nova tehnička dostignuća, kao što su velike građevine (na primer Burdž Kalifa) i objekti nano veličina. Zbog toga što se u oba slučaja unose novi aspekti, i objekti velikih i vrlo malih dimenzija zahtevaju da se, sem sigurnosti, razmotre funkcionalnost i pouzdanost. Za svaku grupu je nekoliko primera prikazano i diskutovano.",
publisher = "Society for Structural Integrity and Life, Institute for Material Testing",
journal = "Integritet i vek konstrukcija",
title = "Significance and applicability of structural integrity assessment, Značaj i primenljivost ocene integriteta konstrukcija",
pages = "30-3",
number = "1",
volume = "12",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2048"
}

Sedmak, S., Radaković, Z., Milović, L.,& Svetel, I.. (2012). Significance and applicability of structural integrity assessment. in Integritet i vek konstrukcija
Society for Structural Integrity and Life, Institute for Material Testing., 12(1), 3-30.
https://hdl.handle.net/21.15107/rcub_technorep_2048

Sedmak S, Radaković Z, Milović L, Svetel I. Significance and applicability of structural integrity assessment. in Integritet i vek konstrukcija. 2012;12(1):3-30.
https://hdl.handle.net/21.15107/rcub_technorep_2048 .

Sedmak, Stojan, Radaković, Zoran, Milović, Ljubica, Svetel, Igor, "Significance and applicability of structural integrity assessment" in Integritet i vek konstrukcija, 12, no. 1 (2012):3-30,
https://hdl.handle.net/21.15107/rcub_technorep_2048 .

TY  - JOUR
AU  - Sedmak, Tamara
AU  - Bakić, Ramo
AU  - Sedmak, Stojan
AU  - Milović, Ljubica
AU  - Kirin, Snežana
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2051
AB  - The risk of brittle fracture of the penstock of the reversible pump turbine is recognized in an early stage of design. To reduce the cost of penstock construction one tunnel is accepted. The HSLA steel of 700 MPa yield stress, 47 mm thick, is selected for the most stressed penstock section. It was necessary to assure structural integrity of welded joints and the penstock structure by involving an appropriate maintenance and repair approach. Maintenance procedures are in continuous development, and the most promising probably is the risk-based approach, developed recently. Basic requirements of this approach are considered in the paper, and the possibility and convenience to apply them for the penstock is evaluated.
AB  - Rizik od krtog loma cevovoda reverzibilne turbine je ocenjen u ranoj fazi projektovanja. Da bi se smanjili troškovi izgradnje cevovoda prihvaćen je jedan tunel. Zbog toga je za najopterećeniji segment cevovoda izabran HSLA čelik, 700 MPa napona tečenja, debljine 47 mm. Bilo je potrebno i da se osigura integritet zavarenih spojeva i konstrukcije cevovoda uvođenjem odgovarajućeg pristupa za održavanje i opravke. Postupci održavanja se neprekidno razvijaju, a možda su najperspektivniji postupci zasnovani na riziku, razvijeni poslednjih godina. U radu su razmotreni osnovni zahtevi novih pristupa, i ocenjena je mogućnost i pogodnost njihove primene na cevovod.
PB  - Society for Structural Integrity and Life, Institute for Material Testing
T2  - Integritet i vek konstrukcija
T1  - Applicability of risk-based maintenance strategy to a penstock
T1  - Strategija održavanja zasnovana na riziku - primenljivost na cevovod
EP  - 196
IS  - 3
SP  - 191
VL  - 12
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2051
ER  - 

@article{
author = "Sedmak, Tamara and Bakić, Ramo and Sedmak, Stojan and Milović, Ljubica and Kirin, Snežana",
year = "2012",
abstract = "The risk of brittle fracture of the penstock of the reversible pump turbine is recognized in an early stage of design. To reduce the cost of penstock construction one tunnel is accepted. The HSLA steel of 700 MPa yield stress, 47 mm thick, is selected for the most stressed penstock section. It was necessary to assure structural integrity of welded joints and the penstock structure by involving an appropriate maintenance and repair approach. Maintenance procedures are in continuous development, and the most promising probably is the risk-based approach, developed recently. Basic requirements of this approach are considered in the paper, and the possibility and convenience to apply them for the penstock is evaluated., Rizik od krtog loma cevovoda reverzibilne turbine je ocenjen u ranoj fazi projektovanja. Da bi se smanjili troškovi izgradnje cevovoda prihvaćen je jedan tunel. Zbog toga je za najopterećeniji segment cevovoda izabran HSLA čelik, 700 MPa napona tečenja, debljine 47 mm. Bilo je potrebno i da se osigura integritet zavarenih spojeva i konstrukcije cevovoda uvođenjem odgovarajućeg pristupa za održavanje i opravke. Postupci održavanja se neprekidno razvijaju, a možda su najperspektivniji postupci zasnovani na riziku, razvijeni poslednjih godina. U radu su razmotreni osnovni zahtevi novih pristupa, i ocenjena je mogućnost i pogodnost njihove primene na cevovod.",
publisher = "Society for Structural Integrity and Life, Institute for Material Testing",
journal = "Integritet i vek konstrukcija",
title = "Applicability of risk-based maintenance strategy to a penstock, Strategija održavanja zasnovana na riziku - primenljivost na cevovod",
pages = "196-191",
number = "3",
volume = "12",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2051"
}

Sedmak, T., Bakić, R., Sedmak, S., Milović, L.,& Kirin, S.. (2012). Applicability of risk-based maintenance strategy to a penstock. in Integritet i vek konstrukcija
Society for Structural Integrity and Life, Institute for Material Testing., 12(3), 191-196.
https://hdl.handle.net/21.15107/rcub_technorep_2051

Sedmak T, Bakić R, Sedmak S, Milović L, Kirin S. Applicability of risk-based maintenance strategy to a penstock. in Integritet i vek konstrukcija. 2012;12(3):191-196.
https://hdl.handle.net/21.15107/rcub_technorep_2051 .

Sedmak, Tamara, Bakić, Ramo, Sedmak, Stojan, Milović, Ljubica, Kirin, Snežana, "Applicability of risk-based maintenance strategy to a penstock" in Integritet i vek konstrukcija, 12, no. 3 (2012):191-196,
https://hdl.handle.net/21.15107/rcub_technorep_2051 .

TY  - JOUR
AU  - Jovičić, Radomir
AU  - Sedmak, Aleksandar
AU  - Sedmak, Stojan
AU  - Milović, Ljubica
AU  - Jovičić, Katarina
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2049
AB  - After the occurrence of water droplets on the manhole outer wall of a storage tank for carbon dioxide, by detailed inspection, a net of cracks is detected in the manhole flange, close to the welded joint between the flange and manhole mantle. Since the droplets are found on the outer side, it is concluded that the through cracks are in question. The analysis of the number and the size of cracks, form and dimensions of manhole cracked segment, the properties of the applied material and stress state has lead to the conclusion that operational safety of the tank is endangered. In order to solve the problem, the damaged zone had to be eliminated and the shape of the manhole neck needed to be redesigned. After performed repairs, the storage tank could be put into operation again.
AB  - Posle pojave vodenih kapi na spoljašnjem zidu otvora za reviziju posude za skladištenje ugljen dioksida, detaljnom inspekcijom je otkrivena mreža prslina na prirubnici revizionog otvora, blizu zavarenog spoja između prirubnice i zida revizionog otvora. Pošto su kapljice uočene na spoljašnjoj strani, zaključuje se da su u pitanju prolazne prsline. Analizom broja i veličine prslina, oblika i dimenzija segmenta naprslog revizionog otvora, osobina primenjenog materijala i naponskog stanja, su doveli do zaključka da je radna sigurnost posude u opasnosti. Da bi se rešio ovaj problem, oštećena zona je morala da se ukloni, a oblik vrata revizionog otvora je morao da se rekonstruiše. Nakon obavljenih popravki, posuda za skladištenje je ponovo puštena u rad.
PB  - Society for Structural Integrity and Life, Institute for Material Testing
T2  - Integritet i vek konstrukcija
T1  - Leakage of an austenitic steel CO2 storage tank
T1  - Curenje posude za skladištenje CO2 od austenitnog čelika
EP  - 108
IS  - 2
SP  - 105
VL  - 12
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2049
ER  - 

@article{
author = "Jovičić, Radomir and Sedmak, Aleksandar and Sedmak, Stojan and Milović, Ljubica and Jovičić, Katarina",
year = "2012",
abstract = "After the occurrence of water droplets on the manhole outer wall of a storage tank for carbon dioxide, by detailed inspection, a net of cracks is detected in the manhole flange, close to the welded joint between the flange and manhole mantle. Since the droplets are found on the outer side, it is concluded that the through cracks are in question. The analysis of the number and the size of cracks, form and dimensions of manhole cracked segment, the properties of the applied material and stress state has lead to the conclusion that operational safety of the tank is endangered. In order to solve the problem, the damaged zone had to be eliminated and the shape of the manhole neck needed to be redesigned. After performed repairs, the storage tank could be put into operation again., Posle pojave vodenih kapi na spoljašnjem zidu otvora za reviziju posude za skladištenje ugljen dioksida, detaljnom inspekcijom je otkrivena mreža prslina na prirubnici revizionog otvora, blizu zavarenog spoja između prirubnice i zida revizionog otvora. Pošto su kapljice uočene na spoljašnjoj strani, zaključuje se da su u pitanju prolazne prsline. Analizom broja i veličine prslina, oblika i dimenzija segmenta naprslog revizionog otvora, osobina primenjenog materijala i naponskog stanja, su doveli do zaključka da je radna sigurnost posude u opasnosti. Da bi se rešio ovaj problem, oštećena zona je morala da se ukloni, a oblik vrata revizionog otvora je morao da se rekonstruiše. Nakon obavljenih popravki, posuda za skladištenje je ponovo puštena u rad.",
publisher = "Society for Structural Integrity and Life, Institute for Material Testing",
journal = "Integritet i vek konstrukcija",
title = "Leakage of an austenitic steel CO2 storage tank, Curenje posude za skladištenje CO2 od austenitnog čelika",
pages = "108-105",
number = "2",
volume = "12",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2049"
}

Jovičić, R., Sedmak, A., Sedmak, S., Milović, L.,& Jovičić, K.. (2012). Leakage of an austenitic steel CO2 storage tank. in Integritet i vek konstrukcija
Society for Structural Integrity and Life, Institute for Material Testing., 12(2), 105-108.
https://hdl.handle.net/21.15107/rcub_technorep_2049

Jovičić R, Sedmak A, Sedmak S, Milović L, Jovičić K. Leakage of an austenitic steel CO2 storage tank. in Integritet i vek konstrukcija. 2012;12(2):105-108.
https://hdl.handle.net/21.15107/rcub_technorep_2049 .

Jovičić, Radomir, Sedmak, Aleksandar, Sedmak, Stojan, Milović, Ljubica, Jovičić, Katarina, "Leakage of an austenitic steel CO2 storage tank" in Integritet i vek konstrukcija, 12, no. 2 (2012):105-108,
https://hdl.handle.net/21.15107/rcub_technorep_2049 .

TY  - JOUR
AU  - Maneski, Taško
AU  - Sedmak, Aleksandar
AU  - Milović, Ljubica
AU  - Fertilio, Antun
AU  - Sedmak, Stojan
PY  - 2006
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/985
AB  - The leakage of tube-tubesheet joint of feedwater heater on the inlet required redesign and repair by additional tube welding. The original design took into account only the sealing, and subsequently after some period leakage occurred due to tube displacement in tubesheet, caused by thermal and mechanical overload. Repair procedure included cutting out the heater header along the welded joint, preparing and welding the tubes to the tubesheet and repeated welding of the header. The header and tubesheet are made of carbon steel. Welding procedure anticipated an austenitic soft interlayer and local heat treatment for residual stress relaxation before final joining. Fitness-for-purpose assessment has been issued and models were developed by finite element analysis according to the design solution and condition after repair. The results of mechanical and thermal responses of model confirmed that repaired feedwater heater is fit for purpose.
AB  - Pricurivanje na spoju cevi i cevne place na ulazu u zagrejač vode je zahtevalo rekonstrukciju i popravku dodatnim zavarivanjem cevi. Prvobitnim projektom je u obzir uzeto samo zaptivanje i posle nekog vremena u radu je došlo do curenja zbog pomeranja cevi u cevnoj ploči, izazvanog termičkim i mehaničkim preopterećenjem. Postupak popravke je predvideo isecanje glave zagrejača po zavarenom spoju, pripremu i zavarivanje cevi za cevnu ploču, i ponovno zavarivanje glave. Glava i cevna ploča su izrađeni od ugljeničnog čelika. Postupak zavarivanja je predvideo austenitni meki sloj i lokalnu termičku obradu za otpuštanje zaostalih napona pre završnog spajanja. Ocena podobnosti za upotrebu je zahtevana i razvijeni su modeli prema projektnom rešenju i stanju posle popravke analizom konačnim elementima Rezultati mehaničkog i termičkog odgovora modela su potvrdili da je popravljeni zagrejač napojne vode podoban za upotrebu.
PB  - Society for Structural Integrity and Life, Institute for Material Testing
T2  - Integritet i vek konstrukcija
T1  - Fitness-for-purpose assessment of repaired feedwater heater
T1  - Ocena podobnosti za upotrebu zagrejača napojne vode posle popravke
EP  - 120
IS  - 3
SP  - 111
VL  - 6
UR  - https://hdl.handle.net/21.15107/rcub_technorep_985
ER  - 

@article{
author = "Maneski, Taško and Sedmak, Aleksandar and Milović, Ljubica and Fertilio, Antun and Sedmak, Stojan",
year = "2006",
abstract = "The leakage of tube-tubesheet joint of feedwater heater on the inlet required redesign and repair by additional tube welding. The original design took into account only the sealing, and subsequently after some period leakage occurred due to tube displacement in tubesheet, caused by thermal and mechanical overload. Repair procedure included cutting out the heater header along the welded joint, preparing and welding the tubes to the tubesheet and repeated welding of the header. The header and tubesheet are made of carbon steel. Welding procedure anticipated an austenitic soft interlayer and local heat treatment for residual stress relaxation before final joining. Fitness-for-purpose assessment has been issued and models were developed by finite element analysis according to the design solution and condition after repair. The results of mechanical and thermal responses of model confirmed that repaired feedwater heater is fit for purpose., Pricurivanje na spoju cevi i cevne place na ulazu u zagrejač vode je zahtevalo rekonstrukciju i popravku dodatnim zavarivanjem cevi. Prvobitnim projektom je u obzir uzeto samo zaptivanje i posle nekog vremena u radu je došlo do curenja zbog pomeranja cevi u cevnoj ploči, izazvanog termičkim i mehaničkim preopterećenjem. Postupak popravke je predvideo isecanje glave zagrejača po zavarenom spoju, pripremu i zavarivanje cevi za cevnu ploču, i ponovno zavarivanje glave. Glava i cevna ploča su izrađeni od ugljeničnog čelika. Postupak zavarivanja je predvideo austenitni meki sloj i lokalnu termičku obradu za otpuštanje zaostalih napona pre završnog spajanja. Ocena podobnosti za upotrebu je zahtevana i razvijeni su modeli prema projektnom rešenju i stanju posle popravke analizom konačnim elementima Rezultati mehaničkog i termičkog odgovora modela su potvrdili da je popravljeni zagrejač napojne vode podoban za upotrebu.",
publisher = "Society for Structural Integrity and Life, Institute for Material Testing",
journal = "Integritet i vek konstrukcija",
title = "Fitness-for-purpose assessment of repaired feedwater heater, Ocena podobnosti za upotrebu zagrejača napojne vode posle popravke",
pages = "120-111",
number = "3",
volume = "6",
url = "https://hdl.handle.net/21.15107/rcub_technorep_985"
}

Maneski, T., Sedmak, A., Milović, L., Fertilio, A.,& Sedmak, S.. (2006). Fitness-for-purpose assessment of repaired feedwater heater. in Integritet i vek konstrukcija
Society for Structural Integrity and Life, Institute for Material Testing., 6(3), 111-120.
https://hdl.handle.net/21.15107/rcub_technorep_985

Maneski T, Sedmak A, Milović L, Fertilio A, Sedmak S. Fitness-for-purpose assessment of repaired feedwater heater. in Integritet i vek konstrukcija. 2006;6(3):111-120.
https://hdl.handle.net/21.15107/rcub_technorep_985 .

Maneski, Taško, Sedmak, Aleksandar, Milović, Ljubica, Fertilio, Antun, Sedmak, Stojan, "Fitness-for-purpose assessment of repaired feedwater heater" in Integritet i vek konstrukcija, 6, no. 3 (2006):111-120,
https://hdl.handle.net/21.15107/rcub_technorep_985 .

TY  - JOUR
AU  - Jallouf, S.
AU  - Milović, Ljubica
AU  - Pluvinage, Guy
AU  - Carmasol, A.
AU  - Sedmak, Stojan
PY  - 2005
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/747
AB  - In this paper SINTAP Level 1 procedure has been used to determine the safety factor and the reliability factor for a boiler tube exhibiting a longitudinal defect inside the tube weld. These factors are obtained using probabilistic FORM/SORM methods. The influence of temperature on the safety and reliability of factors is discussed.
AB  - U radu je korišćen postupak SINTAP nivo 1 za određivanje stepena sigurnosti i faktora pouzdanosti na cevima parnog kotla kod kojih je otkrivena uzdužna prslina u zavarenom spoju. Ovi stepeni su dobijeni pomoću metode verovatnoće SORM/FORM. Razmatra se i uticaj temperature na stepen sigurnosti i faktor pouzdanost.
PB  - Society for Structural Integrity and Life, Institute for Material Testing
T2  - Integritet i vek konstrukcija
T1  - Determination of safety margin and reliability factor of boiler tube with surface crack
T1  - Određivanje stepena sigurnosti i faktora pouzdanosti kotlovskih cevi sa površinskom prslinom
EP  - 162
IS  - 3
SP  - 151
VL  - 5
UR  - https://hdl.handle.net/21.15107/rcub_technorep_747
ER  - 

@article{
author = "Jallouf, S. and Milović, Ljubica and Pluvinage, Guy and Carmasol, A. and Sedmak, Stojan",
year = "2005",
abstract = "In this paper SINTAP Level 1 procedure has been used to determine the safety factor and the reliability factor for a boiler tube exhibiting a longitudinal defect inside the tube weld. These factors are obtained using probabilistic FORM/SORM methods. The influence of temperature on the safety and reliability of factors is discussed., U radu je korišćen postupak SINTAP nivo 1 za određivanje stepena sigurnosti i faktora pouzdanosti na cevima parnog kotla kod kojih je otkrivena uzdužna prslina u zavarenom spoju. Ovi stepeni su dobijeni pomoću metode verovatnoće SORM/FORM. Razmatra se i uticaj temperature na stepen sigurnosti i faktor pouzdanost.",
publisher = "Society for Structural Integrity and Life, Institute for Material Testing",
journal = "Integritet i vek konstrukcija",
title = "Determination of safety margin and reliability factor of boiler tube with surface crack, Određivanje stepena sigurnosti i faktora pouzdanosti kotlovskih cevi sa površinskom prslinom",
pages = "162-151",
number = "3",
volume = "5",
url = "https://hdl.handle.net/21.15107/rcub_technorep_747"
}

Jallouf, S., Milović, L., Pluvinage, G., Carmasol, A.,& Sedmak, S.. (2005). Determination of safety margin and reliability factor of boiler tube with surface crack. in Integritet i vek konstrukcija
Society for Structural Integrity and Life, Institute for Material Testing., 5(3), 151-162.
https://hdl.handle.net/21.15107/rcub_technorep_747

Jallouf S, Milović L, Pluvinage G, Carmasol A, Sedmak S. Determination of safety margin and reliability factor of boiler tube with surface crack. in Integritet i vek konstrukcija. 2005;5(3):151-162.
https://hdl.handle.net/21.15107/rcub_technorep_747 .

Jallouf, S., Milović, Ljubica, Pluvinage, Guy, Carmasol, A., Sedmak, Stojan, "Determination of safety margin and reliability factor of boiler tube with surface crack" in Integritet i vek konstrukcija, 5, no. 3 (2005):151-162,
https://hdl.handle.net/21.15107/rcub_technorep_747 .

TY  - CONF
AU  - Rakin, Marko
AU  - Sedmak, Aleksandar
AU  - Cvijović, Zorica
AU  - Zrilić, Milorad
AU  - Sedmak, Stojan
PY  - 2004
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5399
AB  - We present results of the combined design-theoretical investigation of the mechanism of crack growth at the onset of ductile fracture of NPP reactor pressure vessels. Micromechanical approach to the prediction of ductile fracture has been applied, according to which the volume fraction of voids in the deformed material is determined by the finite-element method. On the basis of CT-specimen tests and known damage parameters, determined for smooth spherical specimens, we propose a micromechanical criterion of crack growth initiation for ductile fracture.
C3  - Strength of Materials
T1  - Micromechanical coupled study of crack growth initiation criterion in pressure vessel steel
EP  - 36
IS  - 1
SP  - 33
VL  - 36
DO  - 10.1023/B:STOM.0000020111.90136.97
ER  - 

@conference{
author = "Rakin, Marko and Sedmak, Aleksandar and Cvijović, Zorica and Zrilić, Milorad and Sedmak, Stojan",
year = "2004",
abstract = "We present results of the combined design-theoretical investigation of the mechanism of crack growth at the onset of ductile fracture of NPP reactor pressure vessels. Micromechanical approach to the prediction of ductile fracture has been applied, according to which the volume fraction of voids in the deformed material is determined by the finite-element method. On the basis of CT-specimen tests and known damage parameters, determined for smooth spherical specimens, we propose a micromechanical criterion of crack growth initiation for ductile fracture.",
journal = "Strength of Materials",
title = "Micromechanical coupled study of crack growth initiation criterion in pressure vessel steel",
pages = "36-33",
number = "1",
volume = "36",
doi = "10.1023/B:STOM.0000020111.90136.97"
}

Rakin, M., Sedmak, A., Cvijović, Z., Zrilić, M.,& Sedmak, S.. (2004). Micromechanical coupled study of crack growth initiation criterion in pressure vessel steel. in Strength of Materials, 36(1), 33-36.
https://doi.org/10.1023/B:STOM.0000020111.90136.97

Rakin M, Sedmak A, Cvijović Z, Zrilić M, Sedmak S. Micromechanical coupled study of crack growth initiation criterion in pressure vessel steel. in Strength of Materials. 2004;36(1):33-36.
doi:10.1023/B:STOM.0000020111.90136.97 .

Rakin, Marko, Sedmak, Aleksandar, Cvijović, Zorica, Zrilić, Milorad, Sedmak, Stojan, "Micromechanical coupled study of crack growth initiation criterion in pressure vessel steel" in Strength of Materials, 36, no. 1 (2004):33-36,
https://doi.org/10.1023/B:STOM.0000020111.90136.97 . .

TY  - JOUR
AU  - Rakin, Marko
AU  - Sedmak, Aleksandar
AU  - Zrilić, Milorad
AU  - Putić, Slaviša
AU  - Sedmak, Stojan
PY  - 2003
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/538
AB  - Pressure vessels are often made of low-alloyed steel that should be characterized by proper values of strenght, toughness, formability and weldability. In this paper the crack initiation in low-alloyed ferritic steel (Rp0.2 ≈ 475 MPa, Rm ≈620 MPa) has been analyzed using micromechanical approach to ductile fracture, where the critical values for material failure are determined by combining both experimental and numerical procedure. The values of the model parameters determined on simple specimens for the material characterization have been successfully used for predicting the onset of stable crack growth on precracked geometry. In that way so-called "transferability" of the micromechanical parameters has been established and their geometry-independence has been confirmed, which is of practical significance for the analysis of integrity of structure with initial cracks.
AB  - U izradi posuda pod pritiskom u znatnoj meri se koriste niskolegirani čelici koji treba da imaju odgovarajuće vrednosti čvrstoće, žilavosti, sposobnosti oblikovanja i zavarljivosti. U radu je analiziran nastanak prsline u niskolegiranom feritnom čeliku (Rp0.2 ≈475 MPa, Rm ≈620 MPa) primenom mikromehaničkog pristupa za žilav lom, gde se kritične vrednosti parametara otkaza materijala određuju kombinovanim eksperimentalno-numeričkim postupkom. Vrednosti parametara modela koje su određene na jednostavnim uzorcima za karakterizaciju materijala, uspešno su korišćene u predviđanju početka stabilnog rasta prsline na geometriji sa početnom prslinom. Time je ostvarena tzv. "prenosivost" mikromehaničkih parametara modela i potvrđena njihova nezavisnost od geometrije, što ima praktičan značaj u analizi integriteta konstrukcija na kojima su otkrivene prsline.
PB  - Savez mašinskih i elektrotehničkih inženjera i tehničara Srbije (SMEITS), Beograd
T2  - Procesna tehnika
T1  - An analysis of occurrence and beginning of stable crack growth in the low-alloyed steel for pressure vessels
T1  - Analiza nastanka i početka stabilnog rasta prsline u niskolegiranom čeliku za posude pod pritiskom
EP  - 81
IS  - 1
SP  - 78
VL  - 19
UR  - https://hdl.handle.net/21.15107/rcub_technorep_538
ER  - 

@article{
author = "Rakin, Marko and Sedmak, Aleksandar and Zrilić, Milorad and Putić, Slaviša and Sedmak, Stojan",
year = "2003",
abstract = "Pressure vessels are often made of low-alloyed steel that should be characterized by proper values of strenght, toughness, formability and weldability. In this paper the crack initiation in low-alloyed ferritic steel (Rp0.2 ≈ 475 MPa, Rm ≈620 MPa) has been analyzed using micromechanical approach to ductile fracture, where the critical values for material failure are determined by combining both experimental and numerical procedure. The values of the model parameters determined on simple specimens for the material characterization have been successfully used for predicting the onset of stable crack growth on precracked geometry. In that way so-called "transferability" of the micromechanical parameters has been established and their geometry-independence has been confirmed, which is of practical significance for the analysis of integrity of structure with initial cracks., U izradi posuda pod pritiskom u znatnoj meri se koriste niskolegirani čelici koji treba da imaju odgovarajuće vrednosti čvrstoće, žilavosti, sposobnosti oblikovanja i zavarljivosti. U radu je analiziran nastanak prsline u niskolegiranom feritnom čeliku (Rp0.2 ≈475 MPa, Rm ≈620 MPa) primenom mikromehaničkog pristupa za žilav lom, gde se kritične vrednosti parametara otkaza materijala određuju kombinovanim eksperimentalno-numeričkim postupkom. Vrednosti parametara modela koje su određene na jednostavnim uzorcima za karakterizaciju materijala, uspešno su korišćene u predviđanju početka stabilnog rasta prsline na geometriji sa početnom prslinom. Time je ostvarena tzv. "prenosivost" mikromehaničkih parametara modela i potvrđena njihova nezavisnost od geometrije, što ima praktičan značaj u analizi integriteta konstrukcija na kojima su otkrivene prsline.",
publisher = "Savez mašinskih i elektrotehničkih inženjera i tehničara Srbije (SMEITS), Beograd",
journal = "Procesna tehnika",
title = "An analysis of occurrence and beginning of stable crack growth in the low-alloyed steel for pressure vessels, Analiza nastanka i početka stabilnog rasta prsline u niskolegiranom čeliku za posude pod pritiskom",
pages = "81-78",
number = "1",
volume = "19",
url = "https://hdl.handle.net/21.15107/rcub_technorep_538"
}

Rakin, M., Sedmak, A., Zrilić, M., Putić, S.,& Sedmak, S.. (2003). An analysis of occurrence and beginning of stable crack growth in the low-alloyed steel for pressure vessels. in Procesna tehnika
Savez mašinskih i elektrotehničkih inženjera i tehničara Srbije (SMEITS), Beograd., 19(1), 78-81.
https://hdl.handle.net/21.15107/rcub_technorep_538

Rakin M, Sedmak A, Zrilić M, Putić S, Sedmak S. An analysis of occurrence and beginning of stable crack growth in the low-alloyed steel for pressure vessels. in Procesna tehnika. 2003;19(1):78-81.
https://hdl.handle.net/21.15107/rcub_technorep_538 .

Rakin, Marko, Sedmak, Aleksandar, Zrilić, Milorad, Putić, Slaviša, Sedmak, Stojan, "An analysis of occurrence and beginning of stable crack growth in the low-alloyed steel for pressure vessels" in Procesna tehnika, 19, no. 1 (2003):78-81,
https://hdl.handle.net/21.15107/rcub_technorep_538 .