Gubeljak, N.

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  • Gubeljak, N. (3)
Projects

Author's Bibliography

Ductile fracture of pipe-ring notched bend specimens - Micromechanical analysis

Musraty, W.; Medjo, B.; Gubeljak, N.; Likeb, A.; Cvijović-Alagić, Ivana; Sedmak, A.; Rakin, Marko P.

(2017)

TY  - JOUR
AU  - Musraty, W.
AU  - Medjo, B.
AU  - Gubeljak, N.
AU  - Likeb, A.
AU  - Cvijović-Alagić, Ivana
AU  - Sedmak, A.
AU  - Rakin, Marko P.
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1532
AB  - Integrity of pipes is typically assessed by testing fracture mechanics specimens, such as compact tensile (CT) or single-edge notched bending (SENB). However, for some pipe dimensions it is not easy or possible to fabricate a specimen conforming to the requirements of standard procedures. A new type of specimen is proposed recently, which can be advantageous for relatively small pipe diameters and axial defects - the pipe ring notch bend specimen - PRNB. In this work, criteria for failure by ductile fracture of PRNB specimens are determined experimentally and by application of micromechanical analysis. The influence of size of the specimen, as well as size and shape of the stress concentrator, is analysed. The results of this study, along with previous authors results, lead to the conclusion that the pipe ring specimens can be applied in integrity assessment of pipes with defects. Also, the benefits of their application include much simpler fabrication and the same material history as the pipe itself. (C) 2017 Elsevier Ltd. All rights reserved.
T2  - Engineering Fracture Mechanics
T1  - Ductile fracture of pipe-ring notched bend specimens - Micromechanical analysis
VL  - 175
SP  - 247
EP  - 261
DO  - 10.1016/j.engfracmech.2017.01.022
ER  - 
@article{
author = "Musraty, W. and Medjo, B. and Gubeljak, N. and Likeb, A. and Cvijović-Alagić, Ivana and Sedmak, A. and Rakin, Marko P.",
year = "2017",
abstract = "Integrity of pipes is typically assessed by testing fracture mechanics specimens, such as compact tensile (CT) or single-edge notched bending (SENB). However, for some pipe dimensions it is not easy or possible to fabricate a specimen conforming to the requirements of standard procedures. A new type of specimen is proposed recently, which can be advantageous for relatively small pipe diameters and axial defects - the pipe ring notch bend specimen - PRNB. In this work, criteria for failure by ductile fracture of PRNB specimens are determined experimentally and by application of micromechanical analysis. The influence of size of the specimen, as well as size and shape of the stress concentrator, is analysed. The results of this study, along with previous authors results, lead to the conclusion that the pipe ring specimens can be applied in integrity assessment of pipes with defects. Also, the benefits of their application include much simpler fabrication and the same material history as the pipe itself. (C) 2017 Elsevier Ltd. All rights reserved.",
journal = "Engineering Fracture Mechanics",
title = "Ductile fracture of pipe-ring notched bend specimens - Micromechanical analysis",
volume = "175",
pages = "247-261",
doi = "10.1016/j.engfracmech.2017.01.022"
}
Musraty, W., Medjo, B., Gubeljak, N., Likeb, A., Cvijović-Alagić, I., Sedmak, A.,& Rakin, M. P.. (2017). Ductile fracture of pipe-ring notched bend specimens - Micromechanical analysis. in Engineering Fracture Mechanics, 175, 247-261.
https://doi.org/10.1016/j.engfracmech.2017.01.022
Musraty W, Medjo B, Gubeljak N, Likeb A, Cvijović-Alagić I, Sedmak A, Rakin MP. Ductile fracture of pipe-ring notched bend specimens - Micromechanical analysis. in Engineering Fracture Mechanics. 2017;175:247-261.
doi:10.1016/j.engfracmech.2017.01.022 .
Musraty, W., Medjo, B., Gubeljak, N., Likeb, A., Cvijović-Alagić, Ivana, Sedmak, A., Rakin, Marko P., "Ductile fracture of pipe-ring notched bend specimens - Micromechanical analysis" in Engineering Fracture Mechanics, 175 (2017):247-261,
https://doi.org/10.1016/j.engfracmech.2017.01.022 . .
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Microstructural morphology effects on fracture resistance and crack tip strain distribution in Ti-6Al-4V alloy for orthopedic implants

Cvijović-Alagić, Ivana; Gubeljak, N.; Rakin, Marko P.; Cvijović, Zorica M.; Geric, K.

(2014)

TY  - JOUR
AU  - Cvijović-Alagić, Ivana
AU  - Gubeljak, N.
AU  - Rakin, Marko P.
AU  - Cvijović, Zorica M.
AU  - Geric, K.
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5755
AB  - The effects of microstructural morphology on the fracture behavior of Ti-6Al-4V ELI (extra-low impurity) alloy in two different heat treatment conditions were examined. Alloy was solution treated above (beta ST) and below (alpha + beta ST) beta transus temperature followed by furnace cooling (FC) in order to obtain the fully lamellar and equiaxed microstructures. Tensile and fracture toughness tests were conducted. The crack tip opening displacement (CTOD) and strain distribution near the crack tip were measured on the compact tension (CT) specimen surface by digital stereometric method. The crack propagation resistance (CTOD-R) curves were developed by applying the modified normalization method and critical CTOD values were determined. To identify the microstructural length scale controlling the fracture resistance of this alloy, the crack propagation path and fracture surface morphology were evaluated. It was found that the reduction in the characteristic microstructural dimension of an order of magnitude and significant change in the alpha phase aspect ratio contribute to drastic increase in the tensile properties and decrease in the crack initiation and propagation resistance. The fully lamellar microstructure displays slightly better biocompatibility because of the lower elastic modulus and superior fracture resistance. The enhanced crack propagation resistance of this microstructure is associated with the larger propensity for crack tip tortuousity, due to the coarser microstructural dimensions (lamellar colony size vs. primary alpha grain size). The difference in the crack propagation modes affects the shape and size of the actual crack tip strain distribution. These results were discussed correlating the complex multiple fracture mechanisms with the stress state in two microstructures. (C) 2013 Elsevier Ltd. All rights reserved.
T2  - Materials and Design
T1  - Microstructural morphology effects on fracture resistance and crack tip strain distribution in Ti-6Al-4V alloy for orthopedic implants
VL  - 53
SP  - 870
EP  - 880
DO  - 10.1016/j.matdes.2013.07.097
ER  - 
@article{
author = "Cvijović-Alagić, Ivana and Gubeljak, N. and Rakin, Marko P. and Cvijović, Zorica M. and Geric, K.",
year = "2014",
abstract = "The effects of microstructural morphology on the fracture behavior of Ti-6Al-4V ELI (extra-low impurity) alloy in two different heat treatment conditions were examined. Alloy was solution treated above (beta ST) and below (alpha + beta ST) beta transus temperature followed by furnace cooling (FC) in order to obtain the fully lamellar and equiaxed microstructures. Tensile and fracture toughness tests were conducted. The crack tip opening displacement (CTOD) and strain distribution near the crack tip were measured on the compact tension (CT) specimen surface by digital stereometric method. The crack propagation resistance (CTOD-R) curves were developed by applying the modified normalization method and critical CTOD values were determined. To identify the microstructural length scale controlling the fracture resistance of this alloy, the crack propagation path and fracture surface morphology were evaluated. It was found that the reduction in the characteristic microstructural dimension of an order of magnitude and significant change in the alpha phase aspect ratio contribute to drastic increase in the tensile properties and decrease in the crack initiation and propagation resistance. The fully lamellar microstructure displays slightly better biocompatibility because of the lower elastic modulus and superior fracture resistance. The enhanced crack propagation resistance of this microstructure is associated with the larger propensity for crack tip tortuousity, due to the coarser microstructural dimensions (lamellar colony size vs. primary alpha grain size). The difference in the crack propagation modes affects the shape and size of the actual crack tip strain distribution. These results were discussed correlating the complex multiple fracture mechanisms with the stress state in two microstructures. (C) 2013 Elsevier Ltd. All rights reserved.",
journal = "Materials and Design",
title = "Microstructural morphology effects on fracture resistance and crack tip strain distribution in Ti-6Al-4V alloy for orthopedic implants",
volume = "53",
pages = "870-880",
doi = "10.1016/j.matdes.2013.07.097"
}
Cvijović-Alagić, I., Gubeljak, N., Rakin, M. P., Cvijović, Z. M.,& Geric, K.. (2014). Microstructural morphology effects on fracture resistance and crack tip strain distribution in Ti-6Al-4V alloy for orthopedic implants. in Materials and Design, 53, 870-880.
https://doi.org/10.1016/j.matdes.2013.07.097
Cvijović-Alagić I, Gubeljak N, Rakin MP, Cvijović ZM, Geric K. Microstructural morphology effects on fracture resistance and crack tip strain distribution in Ti-6Al-4V alloy for orthopedic implants. in Materials and Design. 2014;53:870-880.
doi:10.1016/j.matdes.2013.07.097 .
Cvijović-Alagić, Ivana, Gubeljak, N., Rakin, Marko P., Cvijović, Zorica M., Geric, K., "Microstructural morphology effects on fracture resistance and crack tip strain distribution in Ti-6Al-4V alloy for orthopedic implants" in Materials and Design, 53 (2014):870-880,
https://doi.org/10.1016/j.matdes.2013.07.097 . .
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Micromechanical analysis of constraint effect on fracture initiation in strength mismatched welded

Dobrojevic, M.; Rakin, Marko P.; Gubeljak, N.; Cvijović, Ivana; Zrilic, M.; Krunich, N.; Sedmak, A.

(2007)

TY  - CONF
AU  - Dobrojevic, M.
AU  - Rakin, Marko P.
AU  - Gubeljak, N.
AU  - Cvijović, Ivana
AU  - Zrilic, M.
AU  - Krunich, N.
AU  - Sedmak, A.
PY  - 2007
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6701
AB  - In this paper the micromechanical approach to ductile fracture was applied in a study of constraint effect on crack growth initiation in mismatched welded joints. The single-edged notched bend specimens (precrack length a(0)/W=0.32) were experimentally and numerically analyzed. The coupled micromechanical model proposed by Gurson, Tvergaard and Needleman was used. Constraint effect was tested by varying widths of the welded joints (6, 12 and 18mm). High-strength low-alloyed (HSLA) steel was used as the base metal in a quenched and tempered condition. The flux-cored are-welding process in shielding gas was used. Two different fillers were selected to obtain over- and undermatched weld metal. The micromechanical parameters used in prediction of the crack growth initiation on precracked specimen were calibrated on a round smooth specimen. The difference in fracture behavior between over- and undermatched welded joints obtained in experimental results was followed by numerical computations of void volume fraction in front of the crack tip.
C3  - Materials Science Forum
T1  - Micromechanical analysis of constraint effect on fracture initiation in strength mismatched welded
VL  - 555
SP  - 571
EP  - +
DO  - 10.4028/www.scientific.net/MSF.555.571
ER  - 
@conference{
author = "Dobrojevic, M. and Rakin, Marko P. and Gubeljak, N. and Cvijović, Ivana and Zrilic, M. and Krunich, N. and Sedmak, A.",
year = "2007",
abstract = "In this paper the micromechanical approach to ductile fracture was applied in a study of constraint effect on crack growth initiation in mismatched welded joints. The single-edged notched bend specimens (precrack length a(0)/W=0.32) were experimentally and numerically analyzed. The coupled micromechanical model proposed by Gurson, Tvergaard and Needleman was used. Constraint effect was tested by varying widths of the welded joints (6, 12 and 18mm). High-strength low-alloyed (HSLA) steel was used as the base metal in a quenched and tempered condition. The flux-cored are-welding process in shielding gas was used. Two different fillers were selected to obtain over- and undermatched weld metal. The micromechanical parameters used in prediction of the crack growth initiation on precracked specimen were calibrated on a round smooth specimen. The difference in fracture behavior between over- and undermatched welded joints obtained in experimental results was followed by numerical computations of void volume fraction in front of the crack tip.",
journal = "Materials Science Forum",
title = "Micromechanical analysis of constraint effect on fracture initiation in strength mismatched welded",
volume = "555",
pages = "571-+",
doi = "10.4028/www.scientific.net/MSF.555.571"
}
Dobrojevic, M., Rakin, M. P., Gubeljak, N., Cvijović, I., Zrilic, M., Krunich, N.,& Sedmak, A.. (2007). Micromechanical analysis of constraint effect on fracture initiation in strength mismatched welded. in Materials Science Forum, 555, 571-+.
https://doi.org/10.4028/www.scientific.net/MSF.555.571
Dobrojevic M, Rakin MP, Gubeljak N, Cvijović I, Zrilic M, Krunich N, Sedmak A. Micromechanical analysis of constraint effect on fracture initiation in strength mismatched welded. in Materials Science Forum. 2007;555:571-+.
doi:10.4028/www.scientific.net/MSF.555.571 .
Dobrojevic, M., Rakin, Marko P., Gubeljak, N., Cvijović, Ivana, Zrilic, M., Krunich, N., Sedmak, A., "Micromechanical analysis of constraint effect on fracture initiation in strength mismatched welded" in Materials Science Forum, 555 (2007):571-+,
https://doi.org/10.4028/www.scientific.net/MSF.555.571 . .
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