TY  - JOUR
AU  - Aranđelović, Mihajlo
AU  - Đorđević, Branislav
AU  - Sedmak, Simon
AU  - Radu, Dorin
AU  - Petrović, Ana
AU  - Dikić, Stefan
AU  - Sedmak, Aleksandar
PY  - 2024-06
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7360
AB  - Failure analysis of welded joint with multiple defects was performed taking into account the effect of all defects, not just a dominant one. Four cases of multiple defects in welded joint under the uniaxial tensile loading were investigated using extended Finite Element Method. Two-dimensional Finite Element Models were made according to the tensile specimens with initial crack located in a critical area of welded joint. For each multiple defects case, numerical simulation was performed with three initial crack depth. Engineering Critical Analysis was made using Failure Assessment Diagrams for each defect that was determined as critical for its welded joint case. Numerical simulation showed that the geometry of the most prominent one from a point of view of structural integrity. It was concluded that the vertical misalignment in combination with a secondary defect, had the most adverse effect which can lead to failure of welded structure.
PB  - Elsevier Ltd.
T2  - Engineering Failure Analysis
T1  - Failure analysis of welded joint with multiple defects by extended Finite Element Method and Engineering Critical Analysis
SP  - 108176
VL  - 160
DO  - 10.1016/j.engfailanal.2024.108176
ER  - 

@article{
author = "Aranđelović, Mihajlo and Đorđević, Branislav and Sedmak, Simon and Radu, Dorin and Petrović, Ana and Dikić, Stefan and Sedmak, Aleksandar",
year = "2024-06",
abstract = "Failure analysis of welded joint with multiple defects was performed taking into account the effect of all defects, not just a dominant one. Four cases of multiple defects in welded joint under the uniaxial tensile loading were investigated using extended Finite Element Method. Two-dimensional Finite Element Models were made according to the tensile specimens with initial crack located in a critical area of welded joint. For each multiple defects case, numerical simulation was performed with three initial crack depth. Engineering Critical Analysis was made using Failure Assessment Diagrams for each defect that was determined as critical for its welded joint case. Numerical simulation showed that the geometry of the most prominent one from a point of view of structural integrity. It was concluded that the vertical misalignment in combination with a secondary defect, had the most adverse effect which can lead to failure of welded structure.",
publisher = "Elsevier Ltd.",
journal = "Engineering Failure Analysis",
title = "Failure analysis of welded joint with multiple defects by extended Finite Element Method and Engineering Critical Analysis",
pages = "108176",
volume = "160",
doi = "10.1016/j.engfailanal.2024.108176"
}

Aranđelović, M., Đorđević, B., Sedmak, S., Radu, D., Petrović, A., Dikić, S.,& Sedmak, A.. (2024-06). Failure analysis of welded joint with multiple defects by extended Finite Element Method and Engineering Critical Analysis. in Engineering Failure Analysis
Elsevier Ltd.., 160, 108176.
https://doi.org/10.1016/j.engfailanal.2024.108176

Aranđelović M, Đorđević B, Sedmak S, Radu D, Petrović A, Dikić S, Sedmak A. Failure analysis of welded joint with multiple defects by extended Finite Element Method and Engineering Critical Analysis. in Engineering Failure Analysis. 2024;160:108176.
doi:10.1016/j.engfailanal.2024.108176 .

Aranđelović, Mihajlo, Đorđević, Branislav, Sedmak, Simon, Radu, Dorin, Petrović, Ana, Dikić, Stefan, Sedmak, Aleksandar, "Failure analysis of welded joint with multiple defects by extended Finite Element Method and Engineering Critical Analysis" in Engineering Failure Analysis, 160 (2024-06):108176,
https://doi.org/10.1016/j.engfailanal.2024.108176 . .

TY  - JOUR
AU  - Smoljanić, Tamara
AU  - Milovanović, Aleksa
AU  - Sedmak, Simon
AU  - Milović, Ljubica
AU  - Sedmak, Aleksandar
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7039
AB  - This paper presents development of numerical models for simulation of the behaviour of titanium alloy hip implants under static and dynamic loads, which is a part of extensive research involving the structural integrity of such implants under various loading conditions, as well as under exposure to aggressive environments. Numerical models were created in ABAQUS and ANSYS software packages, in order to determine the stress/strain distribution, the number of cycles to failure and stress intensity factors, for two different hip implant geometries. The ABAQUS models were used for static and ANSYS models for dynamic loads. The next stage in this analysis involved comparing these two cases, to determine the one with the better behaviour, depending on the exploitation conditions, which can greatly vary between different groups of patients. The targeted patient weight for all numerical simulations was 90 kg, while failure assessment diagrams were made for both implant geometries, assuming a crack length of 1 mm.
AB  - U ovom radu je prikazan razvoj numeričkih modela za simulaciju implantata za zamenu zgloba kuka pod
statičkim i dinamičkim opterećenjima, kao deo širokog istraživanja koje uključuje procenu integriteta
implantata kuka u različitim uslovima, kao što su zamor i korozija. Numerički modeli su napravljeni u
ABAQUS i ANSYS softverskim paketima, u cilju procene distribucije napon/deformacija i broja ciklusa do
loma, kao i vrednosti faktora intenziteta napona za dve različite geometrije implanta kuka. ABAQUS
modeli su korišćeni za simulaciju pod statičkim, a ANSYS modeli za simulaciju pod dinamičkim
opterećenjima. Sledeća etapa analize uključuje poređenje ova dva slučaja, kako bi se odredilo koja od
ove dve geometrije pruža bolje ponašanje u eksploatacionim uslovima, a koje mogu značajno varirati
zavisno od pacijenta. Simulacije su vršene za pacijenta mase 90 kg. Za ovu svrhu, dijagrami procene rizika
su napravljeni za obe navedene geometrije, pod pretpostavkom da je dužina inicijalne prsline 1 mm.
PB  - Savez hemijskih inženjera Srbije
T2  - Hemijska industrija
T1  - Numerical simulation of titanium alloy hip replacement implants behaviour under static and dynamic loads
T1  - Numerička simulacija implantata kuka od legure titanijuma pod
statičkim i dinamičkim opterećenjima
EP  - 292
IS  - 4
SP  - 283
VL  - 77
DO  - 10.2298/HEMIND221118026S
ER  - 

@article{
author = "Smoljanić, Tamara and Milovanović, Aleksa and Sedmak, Simon and Milović, Ljubica and Sedmak, Aleksandar",
year = "2023",
abstract = "This paper presents development of numerical models for simulation of the behaviour of titanium alloy hip implants under static and dynamic loads, which is a part of extensive research involving the structural integrity of such implants under various loading conditions, as well as under exposure to aggressive environments. Numerical models were created in ABAQUS and ANSYS software packages, in order to determine the stress/strain distribution, the number of cycles to failure and stress intensity factors, for two different hip implant geometries. The ABAQUS models were used for static and ANSYS models for dynamic loads. The next stage in this analysis involved comparing these two cases, to determine the one with the better behaviour, depending on the exploitation conditions, which can greatly vary between different groups of patients. The targeted patient weight for all numerical simulations was 90 kg, while failure assessment diagrams were made for both implant geometries, assuming a crack length of 1 mm., U ovom radu je prikazan razvoj numeričkih modela za simulaciju implantata za zamenu zgloba kuka pod
statičkim i dinamičkim opterećenjima, kao deo širokog istraživanja koje uključuje procenu integriteta
implantata kuka u različitim uslovima, kao što su zamor i korozija. Numerički modeli su napravljeni u
ABAQUS i ANSYS softverskim paketima, u cilju procene distribucije napon/deformacija i broja ciklusa do
loma, kao i vrednosti faktora intenziteta napona za dve različite geometrije implanta kuka. ABAQUS
modeli su korišćeni za simulaciju pod statičkim, a ANSYS modeli za simulaciju pod dinamičkim
opterećenjima. Sledeća etapa analize uključuje poređenje ova dva slučaja, kako bi se odredilo koja od
ove dve geometrije pruža bolje ponašanje u eksploatacionim uslovima, a koje mogu značajno varirati
zavisno od pacijenta. Simulacije su vršene za pacijenta mase 90 kg. Za ovu svrhu, dijagrami procene rizika
su napravljeni za obe navedene geometrije, pod pretpostavkom da je dužina inicijalne prsline 1 mm.",
publisher = "Savez hemijskih inženjera Srbije",
journal = "Hemijska industrija",
title = "Numerical simulation of titanium alloy hip replacement implants behaviour under static and dynamic loads, Numerička simulacija implantata kuka od legure titanijuma pod
statičkim i dinamičkim opterećenjima",
pages = "292-283",
number = "4",
volume = "77",
doi = "10.2298/HEMIND221118026S"
}

Smoljanić, T., Milovanović, A., Sedmak, S., Milović, L.,& Sedmak, A.. (2023). Numerical simulation of titanium alloy hip replacement implants behaviour under static and dynamic loads. in Hemijska industrija
Savez hemijskih inženjera Srbije., 77(4), 283-292.
https://doi.org/10.2298/HEMIND221118026S

Smoljanić T, Milovanović A, Sedmak S, Milović L, Sedmak A. Numerical simulation of titanium alloy hip replacement implants behaviour under static and dynamic loads. in Hemijska industrija. 2023;77(4):283-292.
doi:10.2298/HEMIND221118026S .

Smoljanić, Tamara, Milovanović, Aleksa, Sedmak, Simon, Milović, Ljubica, Sedmak, Aleksandar, "Numerical simulation of titanium alloy hip replacement implants behaviour under static and dynamic loads" in Hemijska industrija, 77, no. 4 (2023):283-292,
https://doi.org/10.2298/HEMIND221118026S . .

TY  - CONF
AU  - Dikić, Stefan
AU  - Aranđelović, Mihajlo
AU  - Sedmak, Simon
AU  - Petrović, Ana
AU  - Đorđevic, Branislav
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6627
AB  - This paper is based on extensive research about the influence of multiple different welded joint defects on the integrity of welded structures. In this particular case, the focus was on the heat affected zone and its different sub regions - up to this point, it was observed as a whole, with homogeneous mechanical properties along its cross-section. Due to the need to describe its behaviour in more detail, it was concluded that metallographic characterisation of the heat affected zone is necessary. Metallographic tests have provided a detailed insight into the micro-structures with the heat affected zone, which would be difficult to predict in this case, due to specific conditions, i.e., a welding technology which was adopted with the purpose of deliberately causing a number of defects in the welded joint. This would result in a more realistic distribution of mechanical properties along the heat affected zone, which in turn would provide more accurate input data for numerical simulations, since the use of finite element method will be the next step in this research.
PB  - Elsevier B.V.
C3  - Procedia Structural Integrity
T1  - Metallographic characterization of the heat affected zone in welded joints with multiple defects
EP  - 265
SP  - 260
VL  - 48
DO  - 10.1016/j.prostr.2023.07.134
ER  - 

@conference{
author = "Dikić, Stefan and Aranđelović, Mihajlo and Sedmak, Simon and Petrović, Ana and Đorđevic, Branislav",
year = "2023",
abstract = "This paper is based on extensive research about the influence of multiple different welded joint defects on the integrity of welded structures. In this particular case, the focus was on the heat affected zone and its different sub regions - up to this point, it was observed as a whole, with homogeneous mechanical properties along its cross-section. Due to the need to describe its behaviour in more detail, it was concluded that metallographic characterisation of the heat affected zone is necessary. Metallographic tests have provided a detailed insight into the micro-structures with the heat affected zone, which would be difficult to predict in this case, due to specific conditions, i.e., a welding technology which was adopted with the purpose of deliberately causing a number of defects in the welded joint. This would result in a more realistic distribution of mechanical properties along the heat affected zone, which in turn would provide more accurate input data for numerical simulations, since the use of finite element method will be the next step in this research.",
publisher = "Elsevier B.V.",
journal = "Procedia Structural Integrity",
title = "Metallographic characterization of the heat affected zone in welded joints with multiple defects",
pages = "265-260",
volume = "48",
doi = "10.1016/j.prostr.2023.07.134"
}

Dikić, S., Aranđelović, M., Sedmak, S., Petrović, A.,& Đorđevic, B.. (2023). Metallographic characterization of the heat affected zone in welded joints with multiple defects. in Procedia Structural Integrity
Elsevier B.V.., 48, 260-265.
https://doi.org/10.1016/j.prostr.2023.07.134

Dikić S, Aranđelović M, Sedmak S, Petrović A, Đorđevic B. Metallographic characterization of the heat affected zone in welded joints with multiple defects. in Procedia Structural Integrity. 2023;48:260-265.
doi:10.1016/j.prostr.2023.07.134 .

Dikić, Stefan, Aranđelović, Mihajlo, Sedmak, Simon, Petrović, Ana, Đorđevic, Branislav, "Metallographic characterization of the heat affected zone in welded joints with multiple defects" in Procedia Structural Integrity, 48 (2023):260-265,
https://doi.org/10.1016/j.prostr.2023.07.134 . .

TY  - CONF
AU  - Smoljanić, Tamara
AU  - Sedmak, Simon
AU  - Milovanović, Aleksa
AU  - Milović, Ljubica
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6628
AB  - One of the most important aspects of materials typically used in biomedical engineering is their resistance to various unfavourable exploitation conditions, which greatly impact their work life. In terms of extreme conditions, two major factors include fatigue and corrosion, and a combination of these can significantly decrease the expected life of various implants. The focus of this paper will be on hip implants made of Ti-Al6-4V titanium alloy, a material commonly used in such applications, due to its resistance to corrosion and bio-compatibility. Research shown here was based on experimental testing of said alloy in order to determine its mechanical properties under different working environments, including normal, salty and wet conditions. These properties were then used as input data for Extended Finite Element method (XFEM) numerical simulations of fatigue crack growth in hip implants with various geometries. This was of particular interest since specimens which were kept in salty and wet environment had a slight degradation of yield stress and tensile strength, but an increase in plasticity.
PB  - Elsevier B.V.
C3  - Procedia Structural Integrity
T1  - Numerical simulation of fatigue crack growth in Ti-Al6-V4 hip implants under different exploitation conditions
EP  - 221
SP  - 215
VL  - 48
DO  - 10.1016/j.prostr.2023.07.151
UR  - https://hdl.handle.net/21.15107/rcub_technorep_6628
ER  - 

@conference{
author = "Smoljanić, Tamara and Sedmak, Simon and Milovanović, Aleksa and Milović, Ljubica",
year = "2023",
abstract = "One of the most important aspects of materials typically used in biomedical engineering is their resistance to various unfavourable exploitation conditions, which greatly impact their work life. In terms of extreme conditions, two major factors include fatigue and corrosion, and a combination of these can significantly decrease the expected life of various implants. The focus of this paper will be on hip implants made of Ti-Al6-4V titanium alloy, a material commonly used in such applications, due to its resistance to corrosion and bio-compatibility. Research shown here was based on experimental testing of said alloy in order to determine its mechanical properties under different working environments, including normal, salty and wet conditions. These properties were then used as input data for Extended Finite Element method (XFEM) numerical simulations of fatigue crack growth in hip implants with various geometries. This was of particular interest since specimens which were kept in salty and wet environment had a slight degradation of yield stress and tensile strength, but an increase in plasticity.",
publisher = "Elsevier B.V.",
journal = "Procedia Structural Integrity",
title = "Numerical simulation of fatigue crack growth in Ti-Al6-V4 hip implants under different exploitation conditions",
pages = "221-215",
volume = "48",
doi = "10.1016/j.prostr.2023.07.151",
url = "https://hdl.handle.net/21.15107/rcub_technorep_6628"
}

Smoljanić, T., Sedmak, S., Milovanović, A.,& Milović, L.. (2023). Numerical simulation of fatigue crack growth in Ti-Al6-V4 hip implants under different exploitation conditions. in Procedia Structural Integrity
Elsevier B.V.., 48, 215-221.
https://doi.org/10.1016/j.prostr.2023.07.151
https://hdl.handle.net/21.15107/rcub_technorep_6628

Smoljanić T, Sedmak S, Milovanović A, Milović L. Numerical simulation of fatigue crack growth in Ti-Al6-V4 hip implants under different exploitation conditions. in Procedia Structural Integrity. 2023;48:215-221.
doi:10.1016/j.prostr.2023.07.151
https://hdl.handle.net/21.15107/rcub_technorep_6628 .

Smoljanić, Tamara, Sedmak, Simon, Milovanović, Aleksa, Milović, Ljubica, "Numerical simulation of fatigue crack growth in Ti-Al6-V4 hip implants under different exploitation conditions" in Procedia Structural Integrity, 48 (2023):215-221,
https://doi.org/10.1016/j.prostr.2023.07.151 .,
https://hdl.handle.net/21.15107/rcub_technorep_6628 .

TY  - JOUR
AU  - Aranđelović, Mihajlo
AU  - Petrović, Ana
AU  - Đorđević, Branislav
AU  - Sedmak, Simon
AU  - Sedmak, Aleksandar
AU  - Dikić, Stefan
AU  - Radu, Dorin
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5601
AB  - The research represents the ongoing investigation of the welded joints behavior made of low-carbon low-alloyed steel in the presence of different multiple defects. Following the initial experimental and numerical analyses performed on low-grade steel, a set of experiments were performed with specimens made of steel EN 1.0044 (commercial designation S275JR), along with development of new numerical models. Four combinations were made, including defects like undercuts, excess weld metal, misalignment, weld face sagging and incomplete root penetration, considering that these defects are often encountered in practice, and can appear simultaneously. The finite element method (FEM) was used to simulate the experiments. Tensile properties of the HAZ and weld metal were calculated using strain measurements by the digital image correlation (DIC) method. The finite element method (FEM) results were in good agreement with the experimental ones.
PB  - MDPI
T2  - Sustainability
T1  - Effects of Multiple Defects on Welded Joint Behaviour under the Uniaxial Tensile Loading: Fem and Experimental Approach
IS  - 1
SP  - 761
VL  - 15
DO  - 10.3390/su15010761
ER  - 

@article{
author = "Aranđelović, Mihajlo and Petrović, Ana and Đorđević, Branislav and Sedmak, Simon and Sedmak, Aleksandar and Dikić, Stefan and Radu, Dorin",
year = "2023",
abstract = "The research represents the ongoing investigation of the welded joints behavior made of low-carbon low-alloyed steel in the presence of different multiple defects. Following the initial experimental and numerical analyses performed on low-grade steel, a set of experiments were performed with specimens made of steel EN 1.0044 (commercial designation S275JR), along with development of new numerical models. Four combinations were made, including defects like undercuts, excess weld metal, misalignment, weld face sagging and incomplete root penetration, considering that these defects are often encountered in practice, and can appear simultaneously. The finite element method (FEM) was used to simulate the experiments. Tensile properties of the HAZ and weld metal were calculated using strain measurements by the digital image correlation (DIC) method. The finite element method (FEM) results were in good agreement with the experimental ones.",
publisher = "MDPI",
journal = "Sustainability",
title = "Effects of Multiple Defects on Welded Joint Behaviour under the Uniaxial Tensile Loading: Fem and Experimental Approach",
number = "1",
pages = "761",
volume = "15",
doi = "10.3390/su15010761"
}

Aranđelović, M., Petrović, A., Đorđević, B., Sedmak, S., Sedmak, A., Dikić, S.,& Radu, D.. (2023). Effects of Multiple Defects on Welded Joint Behaviour under the Uniaxial Tensile Loading: Fem and Experimental Approach. in Sustainability
MDPI., 15(1), 761.
https://doi.org/10.3390/su15010761

Aranđelović M, Petrović A, Đorđević B, Sedmak S, Sedmak A, Dikić S, Radu D. Effects of Multiple Defects on Welded Joint Behaviour under the Uniaxial Tensile Loading: Fem and Experimental Approach. in Sustainability. 2023;15(1):761.
doi:10.3390/su15010761 .

Aranđelović, Mihajlo, Petrović, Ana, Đorđević, Branislav, Sedmak, Simon, Sedmak, Aleksandar, Dikić, Stefan, Radu, Dorin, "Effects of Multiple Defects on Welded Joint Behaviour under the Uniaxial Tensile Loading: Fem and Experimental Approach" in Sustainability, 15, no. 1 (2023):761,
https://doi.org/10.3390/su15010761 . .

TY  - CONF
AU  - Aranđelović, Mihajlo
AU  - Sedmak, Simon
AU  - Jovičić, Radomir
AU  - Petrović, Ana
AU  - Dikić, Stefan
PY  - 2022
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6422
AB  - This paper presents the continued efforts in investigating behaviour of low-alloyed low-carbon steel welded joints in the presence of different combinations of multiple welding defects, (undercuts, incomplete root penetration, misalignments). Since these defect combinations can greatly affect the integrity of welded joints, due to significant changes in geometry which are induced by their presence. For this reason, a total of 8 numerical models were made, including four different defect combinations (2 models for each group). This number of models was equal to the number of actual test specimens that were used for tensile test experiments, which also provided the necessary input data (mechanical properties) for each model. The goal was to determine if the two models from each group were sufficiently similar to each other, so that in the future research, they could be replaced by a single, unified model for each defect combination. Comparison was made in terms of stress and strain distribution, and it was determined that three out of four models have nearly identical values, whereas the first group specimens had shown slightly bigger differences, which were still acceptable. Thus, it was concluded that a single representative model could be made for each defect combination group.
C3  - ECF23, European Conference on Fracture 2022, Procedia Structural Integrity
T1  - Optimisation of numerical models of welded joints with multiple defect combinations
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6017
ER  - 

@conference{
author = "Aranđelović, Mihajlo and Sedmak, Simon and Jovičić, Radomir and Petrović, Ana and Dikić, Stefan",
year = "2022",
abstract = "This paper presents the continued efforts in investigating behaviour of low-alloyed low-carbon steel welded joints in the presence of different combinations of multiple welding defects, (undercuts, incomplete root penetration, misalignments). Since these defect combinations can greatly affect the integrity of welded joints, due to significant changes in geometry which are induced by their presence. For this reason, a total of 8 numerical models were made, including four different defect combinations (2 models for each group). This number of models was equal to the number of actual test specimens that were used for tensile test experiments, which also provided the necessary input data (mechanical properties) for each model. The goal was to determine if the two models from each group were sufficiently similar to each other, so that in the future research, they could be replaced by a single, unified model for each defect combination. Comparison was made in terms of stress and strain distribution, and it was determined that three out of four models have nearly identical values, whereas the first group specimens had shown slightly bigger differences, which were still acceptable. Thus, it was concluded that a single representative model could be made for each defect combination group.",
journal = "ECF23, European Conference on Fracture 2022, Procedia Structural Integrity",
title = "Optimisation of numerical models of welded joints with multiple defect combinations",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6017"
}

Aranđelović, M., Sedmak, S., Jovičić, R., Petrović, A.,& Dikić, S.. (2022). Optimisation of numerical models of welded joints with multiple defect combinations. in ECF23, European Conference on Fracture 2022, Procedia Structural Integrity.
https://hdl.handle.net/21.15107/rcub_machinery_6017

Aranđelović M, Sedmak S, Jovičić R, Petrović A, Dikić S. Optimisation of numerical models of welded joints with multiple defect combinations. in ECF23, European Conference on Fracture 2022, Procedia Structural Integrity. 2022;.
https://hdl.handle.net/21.15107/rcub_machinery_6017 .

Aranđelović, Mihajlo, Sedmak, Simon, Jovičić, Radomir, Petrović, Ana, Dikić, Stefan, "Optimisation of numerical models of welded joints with multiple defect combinations" in ECF23, European Conference on Fracture 2022, Procedia Structural Integrity (2022),
https://hdl.handle.net/21.15107/rcub_machinery_6017 .

TY  - JOUR
AU  - Kirin, Snežana
AU  - Jeremić, Lazar
AU  - Sedmak, Aleksandar
AU  - Martić, Igor
AU  - Sedmak, Simon
AU  - Vucetić, Ivana
AU  - Golubović, Tamara
PY  - 2020
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4383
AB  - Risk based analysis of reverse hydro power plant penstock structural integrity is performed using fracture mechanics parameters. To assess its structural integrity, extensive testing of the full-scale prototype had been performed, including hydrostatic over-pressurizing, during the design phase. More recently, the Failure Assessment Diagram has been used to evaluate probability, whereas phenomenological analysis has been used to estimate consequence, in the scope of common risk estimation. It is shown that over-pressuring has potential detrimental effect on pipeline safety, i.e. structural integrity.
PB  - Gruppo Italiano Frattura, Cassino
T2  - Frattura Ed Integrita Strutturale
T1  - Risk based analysis of RHPP penstock structural integrity
EP  - 352
IS  - 53
SP  - 345
DO  - 10.3221/IGF-ESIS.53.27
ER  - 

@article{
author = "Kirin, Snežana and Jeremić, Lazar and Sedmak, Aleksandar and Martić, Igor and Sedmak, Simon and Vucetić, Ivana and Golubović, Tamara",
year = "2020",
abstract = "Risk based analysis of reverse hydro power plant penstock structural integrity is performed using fracture mechanics parameters. To assess its structural integrity, extensive testing of the full-scale prototype had been performed, including hydrostatic over-pressurizing, during the design phase. More recently, the Failure Assessment Diagram has been used to evaluate probability, whereas phenomenological analysis has been used to estimate consequence, in the scope of common risk estimation. It is shown that over-pressuring has potential detrimental effect on pipeline safety, i.e. structural integrity.",
publisher = "Gruppo Italiano Frattura, Cassino",
journal = "Frattura Ed Integrita Strutturale",
title = "Risk based analysis of RHPP penstock structural integrity",
pages = "352-345",
number = "53",
doi = "10.3221/IGF-ESIS.53.27"
}

Kirin, S., Jeremić, L., Sedmak, A., Martić, I., Sedmak, S., Vucetić, I.,& Golubović, T.. (2020). Risk based analysis of RHPP penstock structural integrity. in Frattura Ed Integrita Strutturale
Gruppo Italiano Frattura, Cassino.(53), 345-352.
https://doi.org/10.3221/IGF-ESIS.53.27

Kirin S, Jeremić L, Sedmak A, Martić I, Sedmak S, Vucetić I, Golubović T. Risk based analysis of RHPP penstock structural integrity. in Frattura Ed Integrita Strutturale. 2020;(53):345-352.
doi:10.3221/IGF-ESIS.53.27 .

Kirin, Snežana, Jeremić, Lazar, Sedmak, Aleksandar, Martić, Igor, Sedmak, Simon, Vucetić, Ivana, Golubović, Tamara, "Risk based analysis of RHPP penstock structural integrity" in Frattura Ed Integrita Strutturale, no. 53 (2020):345-352,
https://doi.org/10.3221/IGF-ESIS.53.27 . .

TY  - JOUR
AU  - Doncheva, Elisaveta
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Sedmak, Simon
AU  - Trajanoska, Bojana
PY  - 2018
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3786
AB  - The industrial application of high-strength low-alloyed steel (HSLA) in welded structures has increased the demand for understanding fracture behavior and structural integrity assessment of this type of steel and produced welded joints. The aim of this paper is to simulate the experimental evaluation of the fracture mechanics specimens by using the micromechanical model. The investigation is performed on two standard single edge notch bend (SENB) specimens with imposed crack in the central region. Numerical analysis was carried out by using Simulia Abaqus software package on 2D models used to simulate the damage development on the local level. The comparison between numerical and experimental results is presented through measured values of J-integral, load-line displacement vu and crack growth resistance (J-Aa) curves. This paper shows that numerical simulations are promising in respect to their accuracy. The application of this model enables to decrease the amount of expensive experiments for determination of the load level that causes crack propagation.
PB  - Elsevier Science Bv, Amsterdam
T2  - ECF22 - Loading and Environmental Effects on Structural Integrity
T1  - Numerical simulation of crack propagation in high-strength low-alloyed welded steel
EP  - 488
SP  - 483
VL  - 13
DO  - 10.1016/j.prostr.2018.12.080
ER  - 

@article{
author = "Doncheva, Elisaveta and Međo, Bojan and Rakin, Marko and Sedmak, Simon and Trajanoska, Bojana",
year = "2018",
abstract = "The industrial application of high-strength low-alloyed steel (HSLA) in welded structures has increased the demand for understanding fracture behavior and structural integrity assessment of this type of steel and produced welded joints. The aim of this paper is to simulate the experimental evaluation of the fracture mechanics specimens by using the micromechanical model. The investigation is performed on two standard single edge notch bend (SENB) specimens with imposed crack in the central region. Numerical analysis was carried out by using Simulia Abaqus software package on 2D models used to simulate the damage development on the local level. The comparison between numerical and experimental results is presented through measured values of J-integral, load-line displacement vu and crack growth resistance (J-Aa) curves. This paper shows that numerical simulations are promising in respect to their accuracy. The application of this model enables to decrease the amount of expensive experiments for determination of the load level that causes crack propagation.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "ECF22 - Loading and Environmental Effects on Structural Integrity",
title = "Numerical simulation of crack propagation in high-strength low-alloyed welded steel",
pages = "488-483",
volume = "13",
doi = "10.1016/j.prostr.2018.12.080"
}

Doncheva, E., Međo, B., Rakin, M., Sedmak, S.,& Trajanoska, B.. (2018). Numerical simulation of crack propagation in high-strength low-alloyed welded steel. in ECF22 - Loading and Environmental Effects on Structural Integrity
Elsevier Science Bv, Amsterdam., 13, 483-488.
https://doi.org/10.1016/j.prostr.2018.12.080

Doncheva E, Međo B, Rakin M, Sedmak S, Trajanoska B. Numerical simulation of crack propagation in high-strength low-alloyed welded steel. in ECF22 - Loading and Environmental Effects on Structural Integrity. 2018;13:483-488.
doi:10.1016/j.prostr.2018.12.080 .

Doncheva, Elisaveta, Međo, Bojan, Rakin, Marko, Sedmak, Simon, Trajanoska, Bojana, "Numerical simulation of crack propagation in high-strength low-alloyed welded steel" in ECF22 - Loading and Environmental Effects on Structural Integrity, 13 (2018):483-488,
https://doi.org/10.1016/j.prostr.2018.12.080 . .

TY  - JOUR
AU  - Međo, Bojan
AU  - Arsić, Miodrag
AU  - Rakin, Marko
AU  - Sedmak, Simon
AU  - Savić, Zoran
PY  - 2018
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3791
AB  - Vital components of the beam that enable conjoint operation of two bridge cranes are braces and threaded spindle. The beam connects two bridge cranes with overall lifting capacity of 500 t (2 x 250 t) and enables their simultaneous conjoint operation during the rehabilitation or major overhaul of hydroelectric generating set equipment at the hydro power plant ''Djerdap 2'. Two braces are being installed instead of two hooks when this situation occurs. The threaded spindle is loaded with 500 t (5 MN), while braces are loaded with 250 t (2.5 MN) each. Integrity of structures is a relatively new scientific and engineering discipline which in a broader sense comprises condition analysis, behaviour diagnostics, service life evaluation and rehabilitation of structures, which means that beside the usual situation in which it is necessary to evaluate the integrity of a structure when a flaw is detected by means of non-destructive tests, this discipline also comprises stress condition analysis for the crackless structure, most often through the use of finite element method. This is the way to obtain precise and detailed distribution of displacements, deformations and stresses, which enables determination of weak spots on the structure, even before crack initiation. Non-destructive tests are performed in order to analyse the current condition of braces and the threaded spindle. On the basis of performed analytical calculations it is determined that the integrity is not threatened, although some internal non-homogeneities are detected by ultrasonic testing.
PB  - Society for Structural Integrity and Life, Institute for Material Testing
T2  - Structural Integrity and Life
T1  - Integrity assessment of vital beam components that enable conjoint operation of two bridge cranes
EP  - 59
IS  - 1
SP  - 53
VL  - 18
UR  - https://hdl.handle.net/21.15107/rcub_technorep_3791
ER  - 

@article{
author = "Međo, Bojan and Arsić, Miodrag and Rakin, Marko and Sedmak, Simon and Savić, Zoran",
year = "2018",
abstract = "Vital components of the beam that enable conjoint operation of two bridge cranes are braces and threaded spindle. The beam connects two bridge cranes with overall lifting capacity of 500 t (2 x 250 t) and enables their simultaneous conjoint operation during the rehabilitation or major overhaul of hydroelectric generating set equipment at the hydro power plant ''Djerdap 2'. Two braces are being installed instead of two hooks when this situation occurs. The threaded spindle is loaded with 500 t (5 MN), while braces are loaded with 250 t (2.5 MN) each. Integrity of structures is a relatively new scientific and engineering discipline which in a broader sense comprises condition analysis, behaviour diagnostics, service life evaluation and rehabilitation of structures, which means that beside the usual situation in which it is necessary to evaluate the integrity of a structure when a flaw is detected by means of non-destructive tests, this discipline also comprises stress condition analysis for the crackless structure, most often through the use of finite element method. This is the way to obtain precise and detailed distribution of displacements, deformations and stresses, which enables determination of weak spots on the structure, even before crack initiation. Non-destructive tests are performed in order to analyse the current condition of braces and the threaded spindle. On the basis of performed analytical calculations it is determined that the integrity is not threatened, although some internal non-homogeneities are detected by ultrasonic testing.",
publisher = "Society for Structural Integrity and Life, Institute for Material Testing",
journal = "Structural Integrity and Life",
title = "Integrity assessment of vital beam components that enable conjoint operation of two bridge cranes",
pages = "59-53",
number = "1",
volume = "18",
url = "https://hdl.handle.net/21.15107/rcub_technorep_3791"
}

Međo, B., Arsić, M., Rakin, M., Sedmak, S.,& Savić, Z.. (2018). Integrity assessment of vital beam components that enable conjoint operation of two bridge cranes. in Structural Integrity and Life
Society for Structural Integrity and Life, Institute for Material Testing., 18(1), 53-59.
https://hdl.handle.net/21.15107/rcub_technorep_3791

Međo B, Arsić M, Rakin M, Sedmak S, Savić Z. Integrity assessment of vital beam components that enable conjoint operation of two bridge cranes. in Structural Integrity and Life. 2018;18(1):53-59.
https://hdl.handle.net/21.15107/rcub_technorep_3791 .

Međo, Bojan, Arsić, Miodrag, Rakin, Marko, Sedmak, Simon, Savić, Zoran, "Integrity assessment of vital beam components that enable conjoint operation of two bridge cranes" in Structural Integrity and Life, 18, no. 1 (2018):53-59,
https://hdl.handle.net/21.15107/rcub_technorep_3791 .

TY  - JOUR
AU  - Jeremić, Lazar
AU  - Đorđević, Branislav
AU  - Sedmak, Simon
AU  - Sedmak, Aleksandar
AU  - Rakin, Marko
AU  - Arandelović, Mihajlo
PY  - 2018
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3777
AB  - Presented is the effect of plasma hardfacing (or just hardfacing) and carbides presence on the occurrence of cracks and microcracks in the welded layer. The reasons behind this phenomenon are analysed and explained. In addition, the plasma welding technology with all the necessary data such as welding parameters is shown for the case of undamaged tooth of a machine used for the milling of marble. The welded layer with a significant amount of tungsten-carbide is applied onto new, undamaged tooth in order to improve the characteristics of the surface layer of the base material by increasing its hardness which leads to increasing of wear resistance and impact toughness. After welding, the tooth is cut using electrical discharge machining (EDM) for examining the applied surface layer in different locations throughout the welded joint. Macro and microstructural analysis aided in determining the characteristics of the surface layer. The nature and causes of cracks and microcracks are analysed in order to provide a better solution to avoid crack occurrence, as well as in determining their potential effect on the integrity of the tooth as a whole.
PB  - Society for Structural Integrity and Life, Institute for Material Testing
T2  - Structural Integrity and Life
T1  - Effect of plasma hardfacing and carbides presence on the occurrence of cracks and microcracks
EP  - 103
IS  - 2
SP  - 99
VL  - 18
UR  - https://hdl.handle.net/21.15107/rcub_technorep_3777
ER  - 

@article{
author = "Jeremić, Lazar and Đorđević, Branislav and Sedmak, Simon and Sedmak, Aleksandar and Rakin, Marko and Arandelović, Mihajlo",
year = "2018",
abstract = "Presented is the effect of plasma hardfacing (or just hardfacing) and carbides presence on the occurrence of cracks and microcracks in the welded layer. The reasons behind this phenomenon are analysed and explained. In addition, the plasma welding technology with all the necessary data such as welding parameters is shown for the case of undamaged tooth of a machine used for the milling of marble. The welded layer with a significant amount of tungsten-carbide is applied onto new, undamaged tooth in order to improve the characteristics of the surface layer of the base material by increasing its hardness which leads to increasing of wear resistance and impact toughness. After welding, the tooth is cut using electrical discharge machining (EDM) for examining the applied surface layer in different locations throughout the welded joint. Macro and microstructural analysis aided in determining the characteristics of the surface layer. The nature and causes of cracks and microcracks are analysed in order to provide a better solution to avoid crack occurrence, as well as in determining their potential effect on the integrity of the tooth as a whole.",
publisher = "Society for Structural Integrity and Life, Institute for Material Testing",
journal = "Structural Integrity and Life",
title = "Effect of plasma hardfacing and carbides presence on the occurrence of cracks and microcracks",
pages = "103-99",
number = "2",
volume = "18",
url = "https://hdl.handle.net/21.15107/rcub_technorep_3777"
}

Jeremić, L., Đorđević, B., Sedmak, S., Sedmak, A., Rakin, M.,& Arandelović, M.. (2018). Effect of plasma hardfacing and carbides presence on the occurrence of cracks and microcracks. in Structural Integrity and Life
Society for Structural Integrity and Life, Institute for Material Testing., 18(2), 99-103.
https://hdl.handle.net/21.15107/rcub_technorep_3777

Jeremić L, Đorđević B, Sedmak S, Sedmak A, Rakin M, Arandelović M. Effect of plasma hardfacing and carbides presence on the occurrence of cracks and microcracks. in Structural Integrity and Life. 2018;18(2):99-103.
https://hdl.handle.net/21.15107/rcub_technorep_3777 .

Jeremić, Lazar, Đorđević, Branislav, Sedmak, Simon, Sedmak, Aleksandar, Rakin, Marko, Arandelović, Mihajlo, "Effect of plasma hardfacing and carbides presence on the occurrence of cracks and microcracks" in Structural Integrity and Life, 18, no. 2 (2018):99-103,
https://hdl.handle.net/21.15107/rcub_technorep_3777 .

TY  - JOUR
AU  - Međo, Bojan
AU  - Arsić, Miodrag
AU  - Rakin, Marko
AU  - Sedmak, Simon
AU  - Malesević, Zoranka
AU  - Savić, Zoran
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3159
AB  - Vertical Kaplan turbines with nominal power of 176 MW manufactured in Russia are installed in 6 hydroelectric generating sets at hydro power plant 'Djerdap 1' (Kladovo, Serbia). Most of the components are made of materials in accordance to GOST and ASTM standards. During rehabilitation of hydroelectric generating set, the analysis of the current state and integrity assessment of turbine regulation system pipeline required non-destructive tests on parent material and welded joints between pipes and pipes-elbows. The purpose of the regulation system, comprising of the pipeline for the turbine regulator oil supply, is to open and close vanes of the guide vane apparatus and to regulate the position of runner blades and their number of revolutions. Internal pressure in the regulation system is p = 4 MPa. Structural integrity is a recent scientific and engineering discipline which in broader sense comprises state analysis and behaviour diagnostics, service life assessment and rehabilitation of structures, meaning that beside the usual situation where structural integrity assessment is required when flaws are detected by non-destructive testing, this discipline is also includes stress state analysis. This approach is especially important for welded structures, since cracktype flaws can originate from welding and from unfavourable service conditions. In this paper, the results of non-destructive tests referring to the lack of penetration in roots of butt-welded joints between pipes and pipes-elbows, as well as tensile test results of technical specimens with reinforcements and in specimens with parallel machined sides and standard dimensions, are presented in order to carry out the integrity assessment of the turbine regulation system pipeline of hydroelectric generating set A6 at hydro power plant Djerdap 1. Results of analytical strength calculation of butt-welded joints between 2 pipes, and pipe-elbow with a lack of penetration in the root are also presented.
PB  - Society for Structural Integrity and Life, Institute for Material Testing
T2  - Structural Integrity and Life
T1  - Integrity assessment of regulation system pipeline elements in hydroelectric generating set a6 of hydro power plant 'Djerdap 1'
EP  - 78
IS  - 2
SP  - 71
VL  - 16
UR  - https://hdl.handle.net/21.15107/rcub_technorep_3159
ER  - 

@article{
author = "Međo, Bojan and Arsić, Miodrag and Rakin, Marko and Sedmak, Simon and Malesević, Zoranka and Savić, Zoran",
year = "2016",
abstract = "Vertical Kaplan turbines with nominal power of 176 MW manufactured in Russia are installed in 6 hydroelectric generating sets at hydro power plant 'Djerdap 1' (Kladovo, Serbia). Most of the components are made of materials in accordance to GOST and ASTM standards. During rehabilitation of hydroelectric generating set, the analysis of the current state and integrity assessment of turbine regulation system pipeline required non-destructive tests on parent material and welded joints between pipes and pipes-elbows. The purpose of the regulation system, comprising of the pipeline for the turbine regulator oil supply, is to open and close vanes of the guide vane apparatus and to regulate the position of runner blades and their number of revolutions. Internal pressure in the regulation system is p = 4 MPa. Structural integrity is a recent scientific and engineering discipline which in broader sense comprises state analysis and behaviour diagnostics, service life assessment and rehabilitation of structures, meaning that beside the usual situation where structural integrity assessment is required when flaws are detected by non-destructive testing, this discipline is also includes stress state analysis. This approach is especially important for welded structures, since cracktype flaws can originate from welding and from unfavourable service conditions. In this paper, the results of non-destructive tests referring to the lack of penetration in roots of butt-welded joints between pipes and pipes-elbows, as well as tensile test results of technical specimens with reinforcements and in specimens with parallel machined sides and standard dimensions, are presented in order to carry out the integrity assessment of the turbine regulation system pipeline of hydroelectric generating set A6 at hydro power plant Djerdap 1. Results of analytical strength calculation of butt-welded joints between 2 pipes, and pipe-elbow with a lack of penetration in the root are also presented.",
publisher = "Society for Structural Integrity and Life, Institute for Material Testing",
journal = "Structural Integrity and Life",
title = "Integrity assessment of regulation system pipeline elements in hydroelectric generating set a6 of hydro power plant 'Djerdap 1'",
pages = "78-71",
number = "2",
volume = "16",
url = "https://hdl.handle.net/21.15107/rcub_technorep_3159"
}

Međo, B., Arsić, M., Rakin, M., Sedmak, S., Malesević, Z.,& Savić, Z.. (2016). Integrity assessment of regulation system pipeline elements in hydroelectric generating set a6 of hydro power plant 'Djerdap 1'. in Structural Integrity and Life
Society for Structural Integrity and Life, Institute for Material Testing., 16(2), 71-78.
https://hdl.handle.net/21.15107/rcub_technorep_3159

Međo B, Arsić M, Rakin M, Sedmak S, Malesević Z, Savić Z. Integrity assessment of regulation system pipeline elements in hydroelectric generating set a6 of hydro power plant 'Djerdap 1'. in Structural Integrity and Life. 2016;16(2):71-78.
https://hdl.handle.net/21.15107/rcub_technorep_3159 .

Međo, Bojan, Arsić, Miodrag, Rakin, Marko, Sedmak, Simon, Malesević, Zoranka, Savić, Zoran, "Integrity assessment of regulation system pipeline elements in hydroelectric generating set a6 of hydro power plant 'Djerdap 1'" in Structural Integrity and Life, 16, no. 2 (2016):71-78,
https://hdl.handle.net/21.15107/rcub_technorep_3159 .

TY  - JOUR
AU  - Rakin, Marko
AU  - Cvijović, Zorica
AU  - Sedmak, Aleksandar
AU  - Sedmak, S
PY  - 2002
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5371
AB  - For the description of the mechanical behavior of a cracked material, we use a macromechanical model of fracture based on the well-known criterion of plastic yield for porous materials. This model is realized as a computational scheme with the help of the finite-element method. The critical values of the micromechanical parameters of damage are experimentally measured and numerically evaluated for smooth specimens with an aim to predict the onset of plastic yield in a compact cracked specimen. For a low-alloy pressure-vessel steel considered as an example, we show that the proposed micromechanical model can be used for the prediction of the onset of fracture processes in both smooth and compact specimens.
PB  - Springer, New York
T2  - Materials Science
T1  - Analysis of the transferability of micromechanical parameters of damage of steel under the conditions of ductile-fracture initiation
EP  - 113
IS  - 1
SP  - 104
VL  - 38
DO  - 10.1023/A:1020185001499
ER  - 

@article{
author = "Rakin, Marko and Cvijović, Zorica and Sedmak, Aleksandar and Sedmak, S",
year = "2002",
abstract = "For the description of the mechanical behavior of a cracked material, we use a macromechanical model of fracture based on the well-known criterion of plastic yield for porous materials. This model is realized as a computational scheme with the help of the finite-element method. The critical values of the micromechanical parameters of damage are experimentally measured and numerically evaluated for smooth specimens with an aim to predict the onset of plastic yield in a compact cracked specimen. For a low-alloy pressure-vessel steel considered as an example, we show that the proposed micromechanical model can be used for the prediction of the onset of fracture processes in both smooth and compact specimens.",
publisher = "Springer, New York",
journal = "Materials Science",
title = "Analysis of the transferability of micromechanical parameters of damage of steel under the conditions of ductile-fracture initiation",
pages = "113-104",
number = "1",
volume = "38",
doi = "10.1023/A:1020185001499"
}

Rakin, M., Cvijović, Z., Sedmak, A.,& Sedmak, S.. (2002). Analysis of the transferability of micromechanical parameters of damage of steel under the conditions of ductile-fracture initiation. in Materials Science
Springer, New York., 38(1), 104-113.
https://doi.org/10.1023/A:1020185001499

Rakin M, Cvijović Z, Sedmak A, Sedmak S. Analysis of the transferability of micromechanical parameters of damage of steel under the conditions of ductile-fracture initiation. in Materials Science. 2002;38(1):104-113.
doi:10.1023/A:1020185001499 .

Rakin, Marko, Cvijović, Zorica, Sedmak, Aleksandar, Sedmak, S, "Analysis of the transferability of micromechanical parameters of damage of steel under the conditions of ductile-fracture initiation" in Materials Science, 38, no. 1 (2002):104-113,
https://doi.org/10.1023/A:1020185001499 . .