TY  - JOUR
AU  - Sedmak, Simon
AU  - Golubović, Zorana
AU  - Murariu, Alin
AU  - Sedmak, Aleksandar
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2860
AB  - The aim of this paper is to present the behaviour of specimens made of polyethylene material PE 80, subjected to tensile load until failure. Measurements of the temperature distribution have been done using the infrared thermography during specimens loading. Finite element analysis was performed in ABAQUS software, where numerical models were made based on the thermograms and force-displacement diagrams obtained from these experiments. Afterwards, results from the simulation were compared with the experimental results and it was determined in which way the model can be optimized so that these results comply at an acceptable level. Numerical model has shown that the highest values of plastic strain were located near the notch. Value of this plastic strain is several times greater than the values in the remaining parts of the specimen. The numerical analysis also determined that defining the load in displacement form was a much better solution than defining it using the force, since the results have shown much better compliance, and the calculation time was much shorter in this case.
PB  - Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd
T2  - Thermal Science
T1  - Numerical simulation of tensile testing of pe 80 polymer specimens
EP  - 649
IS  - 1
SP  - 641
VL  - 22
DO  - 10.2298/TSCI170219203S
ER  - 

@article{
author = "Sedmak, Simon and Golubović, Zorana and Murariu, Alin and Sedmak, Aleksandar",
year = "2018",
abstract = "The aim of this paper is to present the behaviour of specimens made of polyethylene material PE 80, subjected to tensile load until failure. Measurements of the temperature distribution have been done using the infrared thermography during specimens loading. Finite element analysis was performed in ABAQUS software, where numerical models were made based on the thermograms and force-displacement diagrams obtained from these experiments. Afterwards, results from the simulation were compared with the experimental results and it was determined in which way the model can be optimized so that these results comply at an acceptable level. Numerical model has shown that the highest values of plastic strain were located near the notch. Value of this plastic strain is several times greater than the values in the remaining parts of the specimen. The numerical analysis also determined that defining the load in displacement form was a much better solution than defining it using the force, since the results have shown much better compliance, and the calculation time was much shorter in this case.",
publisher = "Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd",
journal = "Thermal Science",
title = "Numerical simulation of tensile testing of pe 80 polymer specimens",
pages = "649-641",
number = "1",
volume = "22",
doi = "10.2298/TSCI170219203S"
}

Sedmak, S., Golubović, Z., Murariu, A.,& Sedmak, A.. (2018). Numerical simulation of tensile testing of pe 80 polymer specimens. in Thermal Science
Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd., 22(1), 641-649.
https://doi.org/10.2298/TSCI170219203S

Sedmak S, Golubović Z, Murariu A, Sedmak A. Numerical simulation of tensile testing of pe 80 polymer specimens. in Thermal Science. 2018;22(1):641-649.
doi:10.2298/TSCI170219203S .

Sedmak, Simon, Golubović, Zorana, Murariu, Alin, Sedmak, Aleksandar, "Numerical simulation of tensile testing of pe 80 polymer specimens" in Thermal Science, 22, no. 1 (2018):641-649,
https://doi.org/10.2298/TSCI170219203S . .

TY  - JOUR
AU  - Sedmak, Aleksandar
AU  - Tanasković, Drakče
AU  - Murariu, Alin
PY  - 2017
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2621
AB  - Experimental measurement and analytical calculation of preheating, i.e. interpass temperature during multi-pass repair welding has been presented. Analytical calculation is based on heat transfer analysis, whereas measurements have been performed by thermovision camera. Repair welding was performed on crane wheels in the Steelworks Smederevo. Comparison of results indicated that analytical calculation is good enough as the first approximation, but it needs further elaboration, e. g. taking into account the radiation component of heat dissipation and/or temperature dependence of material thermomechanical properties.
PB  - Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd
T2  - Thermal Science
T1  - Experimental and analytical evaluation of preheating temperature during multipass repair welding
EP  - 1009
IS  - 2
SP  - 1003
VL  - 21
DO  - 10.2298/TSCI160324077S
ER  - 

@article{
author = "Sedmak, Aleksandar and Tanasković, Drakče and Murariu, Alin",
year = "2017",
abstract = "Experimental measurement and analytical calculation of preheating, i.e. interpass temperature during multi-pass repair welding has been presented. Analytical calculation is based on heat transfer analysis, whereas measurements have been performed by thermovision camera. Repair welding was performed on crane wheels in the Steelworks Smederevo. Comparison of results indicated that analytical calculation is good enough as the first approximation, but it needs further elaboration, e. g. taking into account the radiation component of heat dissipation and/or temperature dependence of material thermomechanical properties.",
publisher = "Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd",
journal = "Thermal Science",
title = "Experimental and analytical evaluation of preheating temperature during multipass repair welding",
pages = "1009-1003",
number = "2",
volume = "21",
doi = "10.2298/TSCI160324077S"
}

Sedmak, A., Tanasković, D.,& Murariu, A.. (2017). Experimental and analytical evaluation of preheating temperature during multipass repair welding. in Thermal Science
Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd., 21(2), 1003-1009.
https://doi.org/10.2298/TSCI160324077S

Sedmak A, Tanasković D, Murariu A. Experimental and analytical evaluation of preheating temperature during multipass repair welding. in Thermal Science. 2017;21(2):1003-1009.
doi:10.2298/TSCI160324077S .

Sedmak, Aleksandar, Tanasković, Drakče, Murariu, Alin, "Experimental and analytical evaluation of preheating temperature during multipass repair welding" in Thermal Science, 21, no. 2 (2017):1003-1009,
https://doi.org/10.2298/TSCI160324077S . .

TY  - JOUR
AU  - Dojčinović, Marina
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Murariu, Alin
AU  - Malešević, Zoranka
PY  - 2017
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2713
AB  - Hydropower plants need to develop means of protection of turbine and hydromechanical equipment from undesirable occurrences, such as degradation of parent material and/or weld metal of parts and structures caused by stresses and unpredictable influence of vibrations, fatigue, corrosion, erosion and cavitation. Results of tests that refer to the cavitation resistance of turbine runner blades made of cast steel 08X15H4 pi M pi, in accordance with GOST standard are presented in this paper. For the testing of cavitation resistance, the ultrasonic vibration test method is used (with the stationary sample), for which it is necessary to measure the mass loss during specified time intervals, while the cavitation resistance of the material is being defined, taking into account the incubation period and cavitation rate. Scanning electron microscope analysis is carried out to study the morphology of sample damage due to cavitation. The obtained results show that the tested steel has a good cavitation resistance and that fatigue is the main failure mechanism.
PB  - Institut za ispitivanje materijala, Beograd
T2  - Structural Integrity and Life
T1  - Cavitation resistance of turbine runner blades at the hydropower plant 'djerdap'
EP  - 60
IS  - 1
SP  - 55
VL  - 17
UR  - https://hdl.handle.net/21.15107/rcub_technorep_3504
ER  - 

@article{
author = "Dojčinović, Marina and Arsić, Miodrag and Bošnjak, Srđan and Murariu, Alin and Malešević, Zoranka",
year = "2017",
abstract = "Hydropower plants need to develop means of protection of turbine and hydromechanical equipment from undesirable occurrences, such as degradation of parent material and/or weld metal of parts and structures caused by stresses and unpredictable influence of vibrations, fatigue, corrosion, erosion and cavitation. Results of tests that refer to the cavitation resistance of turbine runner blades made of cast steel 08X15H4 pi M pi, in accordance with GOST standard are presented in this paper. For the testing of cavitation resistance, the ultrasonic vibration test method is used (with the stationary sample), for which it is necessary to measure the mass loss during specified time intervals, while the cavitation resistance of the material is being defined, taking into account the incubation period and cavitation rate. Scanning electron microscope analysis is carried out to study the morphology of sample damage due to cavitation. The obtained results show that the tested steel has a good cavitation resistance and that fatigue is the main failure mechanism.",
publisher = "Institut za ispitivanje materijala, Beograd",
journal = "Structural Integrity and Life",
title = "Cavitation resistance of turbine runner blades at the hydropower plant 'djerdap'",
pages = "60-55",
number = "1",
volume = "17",
url = "https://hdl.handle.net/21.15107/rcub_technorep_3504"
}

Dojčinović, M., Arsić, M., Bošnjak, S., Murariu, A.,& Malešević, Z.. (2017). Cavitation resistance of turbine runner blades at the hydropower plant 'djerdap'. in Structural Integrity and Life
Institut za ispitivanje materijala, Beograd., 17(1), 55-60.
https://hdl.handle.net/21.15107/rcub_technorep_3504

Dojčinović M, Arsić M, Bošnjak S, Murariu A, Malešević Z. Cavitation resistance of turbine runner blades at the hydropower plant 'djerdap'. in Structural Integrity and Life. 2017;17(1):55-60.
https://hdl.handle.net/21.15107/rcub_technorep_3504 .

Dojčinović, Marina, Arsić, Miodrag, Bošnjak, Srđan, Murariu, Alin, Malešević, Zoranka, "Cavitation resistance of turbine runner blades at the hydropower plant 'djerdap'" in Structural Integrity and Life, 17, no. 1 (2017):55-60,
https://hdl.handle.net/21.15107/rcub_technorep_3504 .

TY  - JOUR
AU  - Murariu, Alin
AU  - Lozanović Šajić, Jasmina
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2286
AB  - This paper highlights the changes of polyethylene behaviour during various loading rates as well as the influence of test temperature on the material characteristics. Passive infrared thermography method and a high speed infrared camera were used to observe the temperature changes of the sample surface during the tests. The experimental program was carried out on samples taken from PE80 polyethylene gas pipes with simulated imperfections with bilateral V-notch, U-notch, and central hole. Samples have been tensile tested and the results are correlated with the temperature distribution of the samples surface.
PB  - Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd
T2  - Thermal Science
T1  - Temperature and heat effects on polyethylene behaviour in the presence of imperfections
EP  - 1712
IS  - 5
SP  - 1703
VL  - 20
DO  - 10.2298/TSCI151110220M
ER  - 

@article{
author = "Murariu, Alin and Lozanović Šajić, Jasmina",
year = "2016",
abstract = "This paper highlights the changes of polyethylene behaviour during various loading rates as well as the influence of test temperature on the material characteristics. Passive infrared thermography method and a high speed infrared camera were used to observe the temperature changes of the sample surface during the tests. The experimental program was carried out on samples taken from PE80 polyethylene gas pipes with simulated imperfections with bilateral V-notch, U-notch, and central hole. Samples have been tensile tested and the results are correlated with the temperature distribution of the samples surface.",
publisher = "Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd",
journal = "Thermal Science",
title = "Temperature and heat effects on polyethylene behaviour in the presence of imperfections",
pages = "1712-1703",
number = "5",
volume = "20",
doi = "10.2298/TSCI151110220M"
}

Murariu, A.,& Lozanović Šajić, J.. (2016). Temperature and heat effects on polyethylene behaviour in the presence of imperfections. in Thermal Science
Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd., 20(5), 1703-1712.
https://doi.org/10.2298/TSCI151110220M

Murariu A, Lozanović Šajić J. Temperature and heat effects on polyethylene behaviour in the presence of imperfections. in Thermal Science. 2016;20(5):1703-1712.
doi:10.2298/TSCI151110220M .

Murariu, Alin, Lozanović Šajić, Jasmina, "Temperature and heat effects on polyethylene behaviour in the presence of imperfections" in Thermal Science, 20, no. 5 (2016):1703-1712,
https://doi.org/10.2298/TSCI151110220M . .

TY  - JOUR
AU  - Murariu, Alin
AU  - Golubović, Zorana
AU  - Sedmak, Aleksandar
AU  - Kreculj, Dragan D.
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2357
AB  - This paper highlights the changes of polyethylene behaviour during various loading rates. The experimental programme was carried out on samples taken from PE80 polyethylene gas pipes with simulated imperfections with bilateral V-notch, U-notch and central hole. The hybrid technique tensile test - infrared test was used for examining the fracture behaviour of PE80 thermoplastic material samples under different loading rates. Correlation between the loading rate and tensile strength of polyethylene has been established. It has been shown that tensile strength varies with loading rate according to a logarithmic law. Also, it was shown that viscoelastic-plastic character of the polymer material influences directly the specific response of material to loading rates.
PB  - Institut za ispitivanje materijala, Beograd
T2  - Structural Integrity and Life
T1  - Tensile behaviour of polyethylene under different loading rates in the presence of imperfections
EP  - 18
IS  - 1
SP  - 15
VL  - 16
UR  - https://hdl.handle.net/21.15107/rcub_machinery_2357
ER  - 

@article{
author = "Murariu, Alin and Golubović, Zorana and Sedmak, Aleksandar and Kreculj, Dragan D.",
year = "2016",
abstract = "This paper highlights the changes of polyethylene behaviour during various loading rates. The experimental programme was carried out on samples taken from PE80 polyethylene gas pipes with simulated imperfections with bilateral V-notch, U-notch and central hole. The hybrid technique tensile test - infrared test was used for examining the fracture behaviour of PE80 thermoplastic material samples under different loading rates. Correlation between the loading rate and tensile strength of polyethylene has been established. It has been shown that tensile strength varies with loading rate according to a logarithmic law. Also, it was shown that viscoelastic-plastic character of the polymer material influences directly the specific response of material to loading rates.",
publisher = "Institut za ispitivanje materijala, Beograd",
journal = "Structural Integrity and Life",
title = "Tensile behaviour of polyethylene under different loading rates in the presence of imperfections",
pages = "18-15",
number = "1",
volume = "16",
url = "https://hdl.handle.net/21.15107/rcub_machinery_2357"
}

Murariu, A., Golubović, Z., Sedmak, A.,& Kreculj, D. D.. (2016). Tensile behaviour of polyethylene under different loading rates in the presence of imperfections. in Structural Integrity and Life
Institut za ispitivanje materijala, Beograd., 16(1), 15-18.
https://hdl.handle.net/21.15107/rcub_machinery_2357

Murariu A, Golubović Z, Sedmak A, Kreculj DD. Tensile behaviour of polyethylene under different loading rates in the presence of imperfections. in Structural Integrity and Life. 2016;16(1):15-18.
https://hdl.handle.net/21.15107/rcub_machinery_2357 .

Murariu, Alin, Golubović, Zorana, Sedmak, Aleksandar, Kreculj, Dragan D., "Tensile behaviour of polyethylene under different loading rates in the presence of imperfections" in Structural Integrity and Life, 16, no. 1 (2016):15-18,
https://hdl.handle.net/21.15107/rcub_machinery_2357 .

TY  - JOUR
AU  - Murariu, Alin
AU  - Veljić, Darko
AU  - Barjaktarević, Dragana R.
AU  - Rakin, Marko
AU  - Radović, Nenad A.
AU  - Sedmak, Aleksandar
AU  - Djoković, Jelena M.
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2300
AB  - The heat generated during friction stir welding process depends on plastic deformation of the material and friction between the tool and the material. In this work, heat generation is analysed with respect to the material velocity around the tool in Al alloy Al2024-T351 plate. The slip rate of the tool relative to the workpiece material is related to the frictional heat generated. The material velocity, on the other hand, is related to the heat generated by plastic deformation. During the welding process, the slippage is the most pronounced on the front part of the tool shoulder. Also, it is higher on the retreating side than on the advancing side. Slip rate in the zone around the tool pin has very low values, almost negligible. In this zone, the heat generation from friction is very low, because the material is in paste-like state and subjected to intensive plastic deformation. The material flow velocity around the pin is higher in the zone around the root of the pin. In the radial direction, this quantity increases from the pin to the periphery of the tool shoulder.
PB  - Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd
T2  - Thermal Science
T1  - Influence of material velocity on heat generation during linear welding stage of friction stir welding
EP  - 1701
IS  - 5
SP  - 1693
VL  - 20
DO  - 10.2298/TSCI150904217M
ER  - 

@article{
author = "Murariu, Alin and Veljić, Darko and Barjaktarević, Dragana R. and Rakin, Marko and Radović, Nenad A. and Sedmak, Aleksandar and Djoković, Jelena M.",
year = "2016",
abstract = "The heat generated during friction stir welding process depends on plastic deformation of the material and friction between the tool and the material. In this work, heat generation is analysed with respect to the material velocity around the tool in Al alloy Al2024-T351 plate. The slip rate of the tool relative to the workpiece material is related to the frictional heat generated. The material velocity, on the other hand, is related to the heat generated by plastic deformation. During the welding process, the slippage is the most pronounced on the front part of the tool shoulder. Also, it is higher on the retreating side than on the advancing side. Slip rate in the zone around the tool pin has very low values, almost negligible. In this zone, the heat generation from friction is very low, because the material is in paste-like state and subjected to intensive plastic deformation. The material flow velocity around the pin is higher in the zone around the root of the pin. In the radial direction, this quantity increases from the pin to the periphery of the tool shoulder.",
publisher = "Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd",
journal = "Thermal Science",
title = "Influence of material velocity on heat generation during linear welding stage of friction stir welding",
pages = "1701-1693",
number = "5",
volume = "20",
doi = "10.2298/TSCI150904217M"
}

Murariu, A., Veljić, D., Barjaktarević, D. R., Rakin, M., Radović, N. A., Sedmak, A.,& Djoković, J. M.. (2016). Influence of material velocity on heat generation during linear welding stage of friction stir welding. in Thermal Science
Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd., 20(5), 1693-1701.
https://doi.org/10.2298/TSCI150904217M

Murariu A, Veljić D, Barjaktarević DR, Rakin M, Radović NA, Sedmak A, Djoković JM. Influence of material velocity on heat generation during linear welding stage of friction stir welding. in Thermal Science. 2016;20(5):1693-1701.
doi:10.2298/TSCI150904217M .

Murariu, Alin, Veljić, Darko, Barjaktarević, Dragana R., Rakin, Marko, Radović, Nenad A., Sedmak, Aleksandar, Djoković, Jelena M., "Influence of material velocity on heat generation during linear welding stage of friction stir welding" in Thermal Science, 20, no. 5 (2016):1693-1701,
https://doi.org/10.2298/TSCI150904217M . .