TY  - CONF
AU  - Djordjević, Branislav
AU  - Mastilović, Sreten
AU  - Sedmak, Aleksandar
AU  - Dimic, Aleksandar
AU  - Sedmak, Simon
AU  - Arandjelovic, Mihajlo
PY  - 2023
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2069
AB  - The large scatter of the experimental fracture toughness data, characteristic of all ferritic steels in the ductile-to-brittle transition
temperature region, imposed the need to include statistical methods for data processing. Due to the inherent stochasticity, the
application of fracture mechanics concepts in the characterization of the DTB transition phenomenon has remained a challenging
task over the past 50 years. Various models were developed based on statistical approach to data processing in order to capture
the salient features of the phenomenon, but all of them have certain limitations because of the intrinsic complexity of the
problem. However, all these models provided a solid basis for the continued development of new approaches in the
characterization of DTB. Such two novel models are compared herein. They include size effects and utilize scaling of
geometrically similar C(T) specimens, with the aim of obtaining predictions of the fracture toughness. Both proposed models
have the weakest link statistics in common. In the present study, the EURO fracture toughness data set for 22NiMoCr37 reactor
steel is used and the experimental data obtained at temperature of -60 ºC is selected to demonstrate the accuracy of the estimates.
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, taking into account the inherent scatter of the
experimental data. The estimate of KJc cumulative distribution function obtained by extrapolation using the novel two-stepscaling
method is sensitive to the statistical size of the input data sets.
PB  - Elsevier B.V.
C3  - Procedia Structural Integrity
T1  - Comparison of two recent approaches to DTB characterization of ferritic steels
EP  - 596
SP  - 589
VL  - 47
DO  - 10.1016/j.prostr.2023.07.065
ER  - 

@conference{
author = "Djordjević, Branislav and Mastilović, Sreten and Sedmak, Aleksandar and Dimic, Aleksandar and Sedmak, Simon and Arandjelovic, Mihajlo",
year = "2023",
abstract = "The large scatter of the experimental fracture toughness data, characteristic of all ferritic steels in the ductile-to-brittle transition
temperature region, imposed the need to include statistical methods for data processing. Due to the inherent stochasticity, the
application of fracture mechanics concepts in the characterization of the DTB transition phenomenon has remained a challenging
task over the past 50 years. Various models were developed based on statistical approach to data processing in order to capture
the salient features of the phenomenon, but all of them have certain limitations because of the intrinsic complexity of the
problem. However, all these models provided a solid basis for the continued development of new approaches in the
characterization of DTB. Such two novel models are compared herein. They include size effects and utilize scaling of
geometrically similar C(T) specimens, with the aim of obtaining predictions of the fracture toughness. Both proposed models
have the weakest link statistics in common. In the present study, the EURO fracture toughness data set for 22NiMoCr37 reactor
steel is used and the experimental data obtained at temperature of -60 ºC is selected to demonstrate the accuracy of the estimates.
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, taking into account the inherent scatter of the
experimental data. The estimate of KJc cumulative distribution function obtained by extrapolation using the novel two-stepscaling
method is sensitive to the statistical size of the input data sets.",
publisher = "Elsevier B.V.",
journal = "Procedia Structural Integrity",
title = "Comparison of two recent approaches to DTB characterization of ferritic steels",
pages = "596-589",
volume = "47",
doi = "10.1016/j.prostr.2023.07.065"
}

Djordjević, B., Mastilović, S., Sedmak, A., Dimic, A., Sedmak, S.,& Arandjelovic, M.. (2023). Comparison of two recent approaches to DTB characterization of ferritic steels. in Procedia Structural Integrity
Elsevier B.V.., 47, 589-596.
https://doi.org/10.1016/j.prostr.2023.07.065

Djordjević B, Mastilović S, Sedmak A, Dimic A, Sedmak S, Arandjelovic M. Comparison of two recent approaches to DTB characterization of ferritic steels. in Procedia Structural Integrity. 2023;47:589-596.
doi:10.1016/j.prostr.2023.07.065 .

Djordjević, Branislav, Mastilović, Sreten, Sedmak, Aleksandar, Dimic, Aleksandar, Sedmak, Simon, Arandjelovic, Mihajlo, "Comparison of two recent approaches to DTB characterization of ferritic steels" in Procedia Structural Integrity, 47 (2023):589-596,
https://doi.org/10.1016/j.prostr.2023.07.065 . .

TY  - JOUR
AU  - Mastilović, Sreten
AU  - Đorđević, Branislav
AU  - Sedmak, Aleksandar
PY  - 2022
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1536
AB  - Ever since the 1980s there is a sustained interest in the size effect, as one of the most pronounced consequences of fracture mechanics. In the present study, the investigation of the size effect is focused on estimation of the Weibull cumulative distribution function (CDF) of the critical value of the J-integral (J(c)) in the transition temperature region under constraint of a small statistical sample size. Specifically, the J(c) experimental data correspond to the C(T) specimen testing of the reactor pressure-vessel steel 20MnMoNi55 at only two geometrically-similar sizes. Thus, a simple approximate scaling algorithm has been developed to tackle the effect of the C(T) specimen size on the J(c) CDF under these circumstances. Due to the specific form of the two-parameter Weibull CDF, F(J(c) vertical bar beta, eta), the scaling procedure is applied according to a two-step scheme. First, the J(c)-scaling is performed to ensure the approximate overlap of the points that correspond to the CDF value F(J(c) = eta) = 1 - 1/e approximate to 0.632 for different C(T) specimen widths (W), which assumes eta.W-kappa= const. Second, the F-scaling is performed to ensure the equality of the slopes of the CDF in the scaled (F.W(xi)vs. J(c).W-kappa) space. The objective of the sketched approach is to obtain a size-dependent J(c) CDF that encapsulates a reasonably conservative data extrapolation.
PB  - Elsevier
T2  - Engineering Failure Analysis
T1  - A scaling approach to size effect modeling of J(c) CDF for 20MnMoNi55 reactor steel in transition temperature region
VL  - 131
DO  - 10.1016/j.engfailanal.2021.105838
ER  - 

@article{
author = "Mastilović, Sreten and Đorđević, Branislav and Sedmak, Aleksandar",
year = "2022",
abstract = "Ever since the 1980s there is a sustained interest in the size effect, as one of the most pronounced consequences of fracture mechanics. In the present study, the investigation of the size effect is focused on estimation of the Weibull cumulative distribution function (CDF) of the critical value of the J-integral (J(c)) in the transition temperature region under constraint of a small statistical sample size. Specifically, the J(c) experimental data correspond to the C(T) specimen testing of the reactor pressure-vessel steel 20MnMoNi55 at only two geometrically-similar sizes. Thus, a simple approximate scaling algorithm has been developed to tackle the effect of the C(T) specimen size on the J(c) CDF under these circumstances. Due to the specific form of the two-parameter Weibull CDF, F(J(c) vertical bar beta, eta), the scaling procedure is applied according to a two-step scheme. First, the J(c)-scaling is performed to ensure the approximate overlap of the points that correspond to the CDF value F(J(c) = eta) = 1 - 1/e approximate to 0.632 for different C(T) specimen widths (W), which assumes eta.W-kappa= const. Second, the F-scaling is performed to ensure the equality of the slopes of the CDF in the scaled (F.W(xi)vs. J(c).W-kappa) space. The objective of the sketched approach is to obtain a size-dependent J(c) CDF that encapsulates a reasonably conservative data extrapolation.",
publisher = "Elsevier",
journal = "Engineering Failure Analysis",
title = "A scaling approach to size effect modeling of J(c) CDF for 20MnMoNi55 reactor steel in transition temperature region",
volume = "131",
doi = "10.1016/j.engfailanal.2021.105838"
}

Mastilović, S., Đorđević, B.,& Sedmak, A.. (2022). A scaling approach to size effect modeling of J(c) CDF for 20MnMoNi55 reactor steel in transition temperature region. in Engineering Failure Analysis
Elsevier., 131.
https://doi.org/10.1016/j.engfailanal.2021.105838

Mastilović S, Đorđević B, Sedmak A. A scaling approach to size effect modeling of J(c) CDF for 20MnMoNi55 reactor steel in transition temperature region. in Engineering Failure Analysis. 2022;131.
doi:10.1016/j.engfailanal.2021.105838 .

Mastilović, Sreten, Đorđević, Branislav, Sedmak, Aleksandar, "A scaling approach to size effect modeling of J(c) CDF for 20MnMoNi55 reactor steel in transition temperature region" in Engineering Failure Analysis, 131 (2022),
https://doi.org/10.1016/j.engfailanal.2021.105838 . .