Sedmak, Aleksandar

Link to this page

Authority KeyName Variants
143e1bac-dc71-4760-96f8-2c2b7829cd63
  • Sedmak, Aleksandar (3)
Projects

Author's Bibliography

Size Effect Assessment of KJc Experimental Data Using the Two-Step-Scaling Method

Mastilović, Sreten; Djordjević, Branislav; Sedmak, Aleksandar; Kirin, Snežana

(Society for Structural Integrity and Life, 2023)

TY  - CONF
AU  - Mastilović, Sreten
AU  - Djordjević, Branislav
AU  - Sedmak, Aleksandar
AU  - Kirin, Snežana
PY  - 2023
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2098
AB  - The phenomenon of ductile-to-brittle transition (DBT) in ferritic steels, widely used in design of nuclear reactor pres-sure vessels, has been a pervasive semi-centennial research topic. Due to the extremely pronounced experimental data scatter, the statistical approach to characterization of this problem has become inevitable from the earliest analyses. In the present study, the fracture toughness parameters derived from the EURO fracture toughness dataset for 22NiMoCr37 reactor steel are used with the aim to explore the utility of the recently proposed two-step-scaling method. Two widely different temperatures (-154 °C and -91 °C; belonging to the lower shelf and the DBT transition regions of fracture toughness, in respect) are selected to demon-strate the accuracy of extrapolation and interpolation of the fracture toughness CDF (cumulative distribution function) and the pertinent issues related to the method application. The fracture toughness measure used is the critical value of the stress intensity factor used in the master curve KJc (MPa√m). The obtained predictions are in good agreement with the experimental results and well within the inherent experimental data scatter. The prediction of the fracture toughness CDF obtained by extrapolation using the novel two-step-scaling method is reasonably conservative.
PB  - Society for Structural Integrity and Life
C3  - Structural Integrity and Life
T1  - Size Effect Assessment of KJc Experimental Data Using the Two-Step-Scaling Method
EP  - 110
IS  - 2
SP  - 105
VL  - 23
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_2098
ER  - 
@conference{
author = "Mastilović, Sreten and Djordjević, Branislav and Sedmak, Aleksandar and Kirin, Snežana",
year = "2023",
abstract = "The phenomenon of ductile-to-brittle transition (DBT) in ferritic steels, widely used in design of nuclear reactor pres-sure vessels, has been a pervasive semi-centennial research topic. Due to the extremely pronounced experimental data scatter, the statistical approach to characterization of this problem has become inevitable from the earliest analyses. In the present study, the fracture toughness parameters derived from the EURO fracture toughness dataset for 22NiMoCr37 reactor steel are used with the aim to explore the utility of the recently proposed two-step-scaling method. Two widely different temperatures (-154 °C and -91 °C; belonging to the lower shelf and the DBT transition regions of fracture toughness, in respect) are selected to demon-strate the accuracy of extrapolation and interpolation of the fracture toughness CDF (cumulative distribution function) and the pertinent issues related to the method application. The fracture toughness measure used is the critical value of the stress intensity factor used in the master curve KJc (MPa√m). The obtained predictions are in good agreement with the experimental results and well within the inherent experimental data scatter. The prediction of the fracture toughness CDF obtained by extrapolation using the novel two-step-scaling method is reasonably conservative.",
publisher = "Society for Structural Integrity and Life",
journal = "Structural Integrity and Life",
title = "Size Effect Assessment of KJc Experimental Data Using the Two-Step-Scaling Method",
pages = "110-105",
number = "2",
volume = "23",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2098"
}
Mastilović, S., Djordjević, B., Sedmak, A.,& Kirin, S.. (2023). Size Effect Assessment of KJc Experimental Data Using the Two-Step-Scaling Method. in Structural Integrity and Life
Society for Structural Integrity and Life., 23(2), 105-110.
https://hdl.handle.net/21.15107/rcub_rimsi_2098
Mastilović S, Djordjević B, Sedmak A, Kirin S. Size Effect Assessment of KJc Experimental Data Using the Two-Step-Scaling Method. in Structural Integrity and Life. 2023;23(2):105-110.
https://hdl.handle.net/21.15107/rcub_rimsi_2098 .
Mastilović, Sreten, Djordjević, Branislav, Sedmak, Aleksandar, Kirin, Snežana, "Size Effect Assessment of KJc Experimental Data Using the Two-Step-Scaling Method" in Structural Integrity and Life, 23, no. 2 (2023):105-110,
https://hdl.handle.net/21.15107/rcub_rimsi_2098 .

A Note on the Effect of Statistical Sample Size on Fracture Toughness Characterization in the DTB Transition Region

Mastilović, Sreten; Djordjević, Branislav; Sedmak, Aleksandar

(Serbian Society of Mechanics, 2023)

TY  - CONF
AU  - Mastilović, Sreten
AU  - Djordjević, Branislav
AU  - Sedmak, Aleksandar
PY  - 2023
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2068
AB  - The ferritic steels, widely used as pressure-vessel materials in nuclear industry, are prone to embrittlement when exposed to neutron irradiation or temperature reduction within the DTB (ductile-to-brittle) transition region. This embrittlement may be accompanied by the increased size effect, which is a pronounced consequence of fracture mechanics not exhibited in the traditional plasticity theory. Therefore, the fracture toughness in the DTB transition temperature region is a stochastic extrinsic property well known for its aleatory variability. Consequently, the extremely-pronounced experimental data scatter necessitates the use of the statistical approach to material characterization. The recently proposed two-step-scaling approach to estimate the size effect of fracture toughness CDF (cumulative density function) in the DTB transition region relies heavily on regularity of arrangement of experimental data points for the two input sample sizes. This regularity of measurement values becomes an inherently iffy proposition in the case of statistically small data sets. Therefore, the ability of our novel approach to predict objectively the fracture toughness probability outside the experimental domain may be impaired in absence of the sufficient statistical size of the input data sets. Since the large-scale fracture toughness tests for nuclear pressure-vessel steels at low temperatures are very expensive, the present study is concerned with this issue of the statistically sufficient sample size. There are various statistical techniques to determine the sample size needed for a study, including power analysis and sample size calculation formulas. The appropriate method depends on the type of study, the research question, and the statistical analysis planned. These issues are addressed in this article.
PB  - Serbian Society of Mechanics
C3  - Collection of Articles Presented at the Ninth International Congress of the Serbian Society of Mechanics (July 5-7, 2023, Vrnjačka Banja, Serbia)
T1  - A Note on the Effect of Statistical Sample Size on Fracture Toughness Characterization in the DTB Transition Region
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_2068
ER  - 
@conference{
author = "Mastilović, Sreten and Djordjević, Branislav and Sedmak, Aleksandar",
year = "2023",
abstract = "The ferritic steels, widely used as pressure-vessel materials in nuclear industry, are prone to embrittlement when exposed to neutron irradiation or temperature reduction within the DTB (ductile-to-brittle) transition region. This embrittlement may be accompanied by the increased size effect, which is a pronounced consequence of fracture mechanics not exhibited in the traditional plasticity theory. Therefore, the fracture toughness in the DTB transition temperature region is a stochastic extrinsic property well known for its aleatory variability. Consequently, the extremely-pronounced experimental data scatter necessitates the use of the statistical approach to material characterization. The recently proposed two-step-scaling approach to estimate the size effect of fracture toughness CDF (cumulative density function) in the DTB transition region relies heavily on regularity of arrangement of experimental data points for the two input sample sizes. This regularity of measurement values becomes an inherently iffy proposition in the case of statistically small data sets. Therefore, the ability of our novel approach to predict objectively the fracture toughness probability outside the experimental domain may be impaired in absence of the sufficient statistical size of the input data sets. Since the large-scale fracture toughness tests for nuclear pressure-vessel steels at low temperatures are very expensive, the present study is concerned with this issue of the statistically sufficient sample size. There are various statistical techniques to determine the sample size needed for a study, including power analysis and sample size calculation formulas. The appropriate method depends on the type of study, the research question, and the statistical analysis planned. These issues are addressed in this article.",
publisher = "Serbian Society of Mechanics",
journal = "Collection of Articles Presented at the Ninth International Congress of the Serbian Society of Mechanics (July 5-7, 2023, Vrnjačka Banja, Serbia)",
title = "A Note on the Effect of Statistical Sample Size on Fracture Toughness Characterization in the DTB Transition Region",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2068"
}
Mastilović, S., Djordjević, B.,& Sedmak, A.. (2023). A Note on the Effect of Statistical Sample Size on Fracture Toughness Characterization in the DTB Transition Region. in Collection of Articles Presented at the Ninth International Congress of the Serbian Society of Mechanics (July 5-7, 2023, Vrnjačka Banja, Serbia)
Serbian Society of Mechanics..
https://hdl.handle.net/21.15107/rcub_rimsi_2068
Mastilović S, Djordjević B, Sedmak A. A Note on the Effect of Statistical Sample Size on Fracture Toughness Characterization in the DTB Transition Region. in Collection of Articles Presented at the Ninth International Congress of the Serbian Society of Mechanics (July 5-7, 2023, Vrnjačka Banja, Serbia). 2023;.
https://hdl.handle.net/21.15107/rcub_rimsi_2068 .
Mastilović, Sreten, Djordjević, Branislav, Sedmak, Aleksandar, "A Note on the Effect of Statistical Sample Size on Fracture Toughness Characterization in the DTB Transition Region" in Collection of Articles Presented at the Ninth International Congress of the Serbian Society of Mechanics (July 5-7, 2023, Vrnjačka Banja, Serbia) (2023),
https://hdl.handle.net/21.15107/rcub_rimsi_2068 .

History of ductile-to-brittle transition problem of ferritic steels

Djordjevic, Branislav; Sedmak, Aleksandar; Mastilović, Sreten; Popovic, Olivera; Kirin, Snezana

(Elsevier, 2022)

TY  - CONF
AU  - Djordjevic, Branislav
AU  - Sedmak, Aleksandar
AU  - Mastilović, Sreten
AU  - Popovic, Olivera
AU  - Kirin, Snezana
PY  - 2022
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1643
AB  - This paper presents a review of different approaches through history concerning DTB transition phenomenon of ferritic steels and
their characterization using FM concept, from the earliest studies based on LEFM to the application of the EPFM concept. The
large scattering of the experimental fracture toughness data, characteristic of all ferritic steels in the transition temperature region,
has imposed the need of including statistical methods for data processing. Such approach that began in the 1970s can be encountered
even nowadays as the base of fracture toughness data interpretation in DTB problems. An overview of studies with statistical
interpretation of experimental data in the transition temperature region is also given. Aforementioned provides a foundation for
novel approaches in DTB transition problems, which include size effects and scaling of geometrically similar specimens.
PB  - Elsevier
C3  - Procedia Structural Integrity
T1  - History of ductile-to-brittle transition problem of ferritic steels
EP  - 95
SP  - 88
VL  - 42
DO  - 10.1016/j.prostr.2022.12.010
ER  - 
@conference{
author = "Djordjevic, Branislav and Sedmak, Aleksandar and Mastilović, Sreten and Popovic, Olivera and Kirin, Snezana",
year = "2022",
abstract = "This paper presents a review of different approaches through history concerning DTB transition phenomenon of ferritic steels and
their characterization using FM concept, from the earliest studies based on LEFM to the application of the EPFM concept. The
large scattering of the experimental fracture toughness data, characteristic of all ferritic steels in the transition temperature region,
has imposed the need of including statistical methods for data processing. Such approach that began in the 1970s can be encountered
even nowadays as the base of fracture toughness data interpretation in DTB problems. An overview of studies with statistical
interpretation of experimental data in the transition temperature region is also given. Aforementioned provides a foundation for
novel approaches in DTB transition problems, which include size effects and scaling of geometrically similar specimens.",
publisher = "Elsevier",
journal = "Procedia Structural Integrity",
title = "History of ductile-to-brittle transition problem of ferritic steels",
pages = "95-88",
volume = "42",
doi = "10.1016/j.prostr.2022.12.010"
}
Djordjevic, B., Sedmak, A., Mastilović, S., Popovic, O.,& Kirin, S.. (2022). History of ductile-to-brittle transition problem of ferritic steels. in Procedia Structural Integrity
Elsevier., 42, 88-95.
https://doi.org/10.1016/j.prostr.2022.12.010
Djordjevic B, Sedmak A, Mastilović S, Popovic O, Kirin S. History of ductile-to-brittle transition problem of ferritic steels. in Procedia Structural Integrity. 2022;42:88-95.
doi:10.1016/j.prostr.2022.12.010 .
Djordjevic, Branislav, Sedmak, Aleksandar, Mastilović, Sreten, Popovic, Olivera, Kirin, Snezana, "History of ductile-to-brittle transition problem of ferritic steels" in Procedia Structural Integrity, 42 (2022):88-95,
https://doi.org/10.1016/j.prostr.2022.12.010 . .
2