TY  - JOUR
AU  - Momčilović, Nikola
AU  - Ilić, Nemanja
AU  - Kalajdžić, Milan
AU  - Ivošević, Špiro
AU  - Petrović, Ana
PY  - 2024
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7797
AB  - Standard structural assessments of ship hulls include the evaluation of the elastic structural response. Elastic analysis neglects extreme and unpredicted loadings, which can produce catastrophic outcomes, such as the loss of the ship’s ultimate strength. Moreover, hull elements are considered unaffected by age-related degradation. Therefore, this study models and quantifies the effect of corrosion-induced structural degradation on the ultimate strength of a high-tensile-steel (HTS) cargo ship using progressive collapse and nonlinear finite element methods. Uniform and pitting corrosion are modeled through selected scenarios, which hull elements might encounter during exploitation, producing a total of 148 calculation models. The findings show that corrosion-induced degradation can significantly decrease the ultimate strength of the hull (up to 30% for the most severe scenarios assessed). Furthermore, ultimate strength decreases almost proportionally to the amount of wastage considered. It was found that stiffener corrosion has a significant effect on the total ultimate strength. This study’s aim is to emphasize the vast importance of including ultimate strength along with ageing effects in industry-standard structural assessments of large HTS ship structures, designed to last for several decades whilst exposed to excessive and unpredicted bending moments.
PB  - MDPI
T2  - Journal of Marine Science and Engineering
T1  - Effect of Corrosion-Induced Structural Degradation on the Ultimate Strength of a High-Tensile-Steel Ship Hull
IS  - 5
SP  - 745
VL  - 12
DO  - 10.3390/jmse12050745
ER  - 

@article{
author = "Momčilović, Nikola and Ilić, Nemanja and Kalajdžić, Milan and Ivošević, Špiro and Petrović, Ana",
year = "2024",
abstract = "Standard structural assessments of ship hulls include the evaluation of the elastic structural response. Elastic analysis neglects extreme and unpredicted loadings, which can produce catastrophic outcomes, such as the loss of the ship’s ultimate strength. Moreover, hull elements are considered unaffected by age-related degradation. Therefore, this study models and quantifies the effect of corrosion-induced structural degradation on the ultimate strength of a high-tensile-steel (HTS) cargo ship using progressive collapse and nonlinear finite element methods. Uniform and pitting corrosion are modeled through selected scenarios, which hull elements might encounter during exploitation, producing a total of 148 calculation models. The findings show that corrosion-induced degradation can significantly decrease the ultimate strength of the hull (up to 30% for the most severe scenarios assessed). Furthermore, ultimate strength decreases almost proportionally to the amount of wastage considered. It was found that stiffener corrosion has a significant effect on the total ultimate strength. This study’s aim is to emphasize the vast importance of including ultimate strength along with ageing effects in industry-standard structural assessments of large HTS ship structures, designed to last for several decades whilst exposed to excessive and unpredicted bending moments.",
publisher = "MDPI",
journal = "Journal of Marine Science and Engineering",
title = "Effect of Corrosion-Induced Structural Degradation on the Ultimate Strength of a High-Tensile-Steel Ship Hull",
number = "5",
pages = "745",
volume = "12",
doi = "10.3390/jmse12050745"
}

Momčilović, N., Ilić, N., Kalajdžić, M., Ivošević, Š.,& Petrović, A.. (2024). Effect of Corrosion-Induced Structural Degradation on the Ultimate Strength of a High-Tensile-Steel Ship Hull. in Journal of Marine Science and Engineering
MDPI., 12(5), 745.
https://doi.org/10.3390/jmse12050745

Momčilović N, Ilić N, Kalajdžić M, Ivošević Š, Petrović A. Effect of Corrosion-Induced Structural Degradation on the Ultimate Strength of a High-Tensile-Steel Ship Hull. in Journal of Marine Science and Engineering. 2024;12(5):745.
doi:10.3390/jmse12050745 .

Momčilović, Nikola, Ilić, Nemanja, Kalajdžić, Milan, Ivošević, Špiro, Petrović, Ana, "Effect of Corrosion-Induced Structural Degradation on the Ultimate Strength of a High-Tensile-Steel Ship Hull" in Journal of Marine Science and Engineering, 12, no. 5 (2024):745,
https://doi.org/10.3390/jmse12050745 . .

TY  - CONF
AU  - Momčilović, Nikola
AU  - Ilić, Nemanja
AU  - Kalajdžić, Milan
AU  - Ivošević, Špiro
AU  - Petrović, Ana
PY  - 2023
UR  - https://www.sciencedirect.com/science/article/pii/S245232162300522X
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7291
AB  - In general, ship structural integrity assessments consist of prescribed procedures given by the rules of classification societies, and if necessary, direct calculations. Direct calculations mostly include longitudinal strength analyses and buckling calculations for various service loadings and structural members. Resulting stress is compared to the allowable stress, which is also rule-prescribed and acts as a share of the yield stress of the material. This means that the structure is evaluated upon its elastic response. Moreover, ship structural assessments consider as-built scantlings, not diminished by ageing. Generally, extreme or once-in-a-lifetime loadings are neglected. They can include overloading scenarios that lead to the ship structural collapse or the loss of the ship’s carrying capacity, i.e., ultimate strength. Ultimate strength of the ship is represented by the maximum (ultimate) bending moment the structure can withstand. Its evaluation is important to determine the ship’s structural safety level with respect to its collapse. Therefore, this paper delivers the ultimate strength assessment for a typical bulk carrier having 180 m in length. For this purpose, an incremental-iterative progressivecollapse analysis (PCA) is used. In the first stage, ultimate strength of a bulk carrier is determined using as-built scantlings. In the next, ageing effects are considered within PCA by modeling scenarios that include both pitting and uniform corrosion. Pitting corrosion is defined by pitting intensity degree (DOP) and corrosion intensity degree (DOC), whilst the uniform corrosion is defined by thickness reduction. Results show that corrosion effects can significantly diminish the ultimate strength of the ship. This means that, in the design phase, structural assessments cannot be based just on as-built scantlings, but also might include ageing effects, as ships are designed to be reliable on the long-term.
C3  - Procedia Structural Integrity
T1  - Pitting and uniform corrosion effects on ultimate strength of a  bulk carrier
EP  - 18
SP  - 12
VL  - 48
DO  - 10.1016/j.prostr.2023.07.104
ER  - 

@conference{
author = "Momčilović, Nikola and Ilić, Nemanja and Kalajdžić, Milan and Ivošević, Špiro and Petrović, Ana",
year = "2023",
abstract = "In general, ship structural integrity assessments consist of prescribed procedures given by the rules of classification societies, and if necessary, direct calculations. Direct calculations mostly include longitudinal strength analyses and buckling calculations for various service loadings and structural members. Resulting stress is compared to the allowable stress, which is also rule-prescribed and acts as a share of the yield stress of the material. This means that the structure is evaluated upon its elastic response. Moreover, ship structural assessments consider as-built scantlings, not diminished by ageing. Generally, extreme or once-in-a-lifetime loadings are neglected. They can include overloading scenarios that lead to the ship structural collapse or the loss of the ship’s carrying capacity, i.e., ultimate strength. Ultimate strength of the ship is represented by the maximum (ultimate) bending moment the structure can withstand. Its evaluation is important to determine the ship’s structural safety level with respect to its collapse. Therefore, this paper delivers the ultimate strength assessment for a typical bulk carrier having 180 m in length. For this purpose, an incremental-iterative progressivecollapse analysis (PCA) is used. In the first stage, ultimate strength of a bulk carrier is determined using as-built scantlings. In the next, ageing effects are considered within PCA by modeling scenarios that include both pitting and uniform corrosion. Pitting corrosion is defined by pitting intensity degree (DOP) and corrosion intensity degree (DOC), whilst the uniform corrosion is defined by thickness reduction. Results show that corrosion effects can significantly diminish the ultimate strength of the ship. This means that, in the design phase, structural assessments cannot be based just on as-built scantlings, but also might include ageing effects, as ships are designed to be reliable on the long-term.",
journal = "Procedia Structural Integrity",
title = "Pitting and uniform corrosion effects on ultimate strength of a  bulk carrier",
pages = "18-12",
volume = "48",
doi = "10.1016/j.prostr.2023.07.104"
}

Momčilović, N., Ilić, N., Kalajdžić, M., Ivošević, Š.,& Petrović, A.. (2023). Pitting and uniform corrosion effects on ultimate strength of a  bulk carrier. in Procedia Structural Integrity, 48, 12-18.
https://doi.org/10.1016/j.prostr.2023.07.104

Momčilović N, Ilić N, Kalajdžić M, Ivošević Š, Petrović A. Pitting and uniform corrosion effects on ultimate strength of a  bulk carrier. in Procedia Structural Integrity. 2023;48:12-18.
doi:10.1016/j.prostr.2023.07.104 .

Momčilović, Nikola, Ilić, Nemanja, Kalajdžić, Milan, Ivošević, Špiro, Petrović, Ana, "Pitting and uniform corrosion effects on ultimate strength of a  bulk carrier" in Procedia Structural Integrity, 48 (2023):12-18,
https://doi.org/10.1016/j.prostr.2023.07.104 . .

TY  - JOUR
AU  - Ivošević, Špiro
AU  - Kovač, Nataša
AU  - Momčilović, Nikola
AU  - Vukelić, Goran
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4243
AB  - The longitudinal girder (LG) between fuel oil tanks (FOT) and water ballast tanks in the double bottoms of ships represent critical structural parts whose watertight nature could be harmed by corrosion, thus, causing the pollution of water ballast tanks and adjacent areas. The new common structural rules (CSR) define the minimum thickness values of structural elements and corrosion margins. The assessment of the deviations from the prescribed values during ship operation could optimize the prescribed criteria. Assuming that corrosive processes begin after four years of operation, the paper analyzes a linear model that describes the percentage of plate wear as a function of the built-in thickness of LG of FOT. The research included 20 ships and provided the database for 1918 corrosion depth values. The gauging records included the average values of the original thickness of steel plates grouped in three intervals (11–13 mm, 13–15 mm, 15–18 mm). Based on the difference between the built-in and subsequently measured values, the paper analyzes the percentage of thickness reduction due to corrosion, concerning the original plate thickness. The findings of the research should facilitate the optimization of corrosion margins and prevent potential structural collapse and pollution.
PB  - MDPI
T2  - Journal of Marine Science and Engineering
T1  - Evaluation of the Corrosion Depth of Double Bottom Longitudinal Girder on Aging Bulk Carriers
IS  - 10
SP  - 1425
VL  - 10
DO  - doi.org/10.3390/jmse10101425
ER  - 

@article{
author = "Ivošević, Špiro and Kovač, Nataša and Momčilović, Nikola and Vukelić, Goran",
year = "2022",
abstract = "The longitudinal girder (LG) between fuel oil tanks (FOT) and water ballast tanks in the double bottoms of ships represent critical structural parts whose watertight nature could be harmed by corrosion, thus, causing the pollution of water ballast tanks and adjacent areas. The new common structural rules (CSR) define the minimum thickness values of structural elements and corrosion margins. The assessment of the deviations from the prescribed values during ship operation could optimize the prescribed criteria. Assuming that corrosive processes begin after four years of operation, the paper analyzes a linear model that describes the percentage of plate wear as a function of the built-in thickness of LG of FOT. The research included 20 ships and provided the database for 1918 corrosion depth values. The gauging records included the average values of the original thickness of steel plates grouped in three intervals (11–13 mm, 13–15 mm, 15–18 mm). Based on the difference between the built-in and subsequently measured values, the paper analyzes the percentage of thickness reduction due to corrosion, concerning the original plate thickness. The findings of the research should facilitate the optimization of corrosion margins and prevent potential structural collapse and pollution.",
publisher = "MDPI",
journal = "Journal of Marine Science and Engineering",
title = "Evaluation of the Corrosion Depth of Double Bottom Longitudinal Girder on Aging Bulk Carriers",
number = "10",
pages = "1425",
volume = "10",
doi = "doi.org/10.3390/jmse10101425"
}

Ivošević, Š., Kovač, N., Momčilović, N.,& Vukelić, G.. (2022). Evaluation of the Corrosion Depth of Double Bottom Longitudinal Girder on Aging Bulk Carriers. in Journal of Marine Science and Engineering
MDPI., 10(10), 1425.
https://doi.org/doi.org/10.3390/jmse10101425

Ivošević Š, Kovač N, Momčilović N, Vukelić G. Evaluation of the Corrosion Depth of Double Bottom Longitudinal Girder on Aging Bulk Carriers. in Journal of Marine Science and Engineering. 2022;10(10):1425.
doi:doi.org/10.3390/jmse10101425 .

Ivošević, Špiro, Kovač, Nataša, Momčilović, Nikola, Vukelić, Goran, "Evaluation of the Corrosion Depth of Double Bottom Longitudinal Girder on Aging Bulk Carriers" in Journal of Marine Science and Engineering, 10, no. 10 (2022):1425,
https://doi.org/doi.org/10.3390/jmse10101425 . .