TY  - JOUR
AU  - Raković, Dragan
AU  - Simonović, Aleksandar
AU  - Grbović, Aleksandar
AU  - Radović, Ljubica
AU  - Vorkapić, Miloš
AU  - Krstić, Branimir
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4783
AB  - This paper presents the failure analysis results of the helicopter skid landing gear. The helicopter skid landing gear fractured while the helicopter was on the ground at the airport. The aft cross tube of the landing gear assembly was found fractured into two pieces. Observation of crack propagation area at low magnification revealed numerous secondary cracks, inner surface irregularities while fracture surface indicated fatigue process. Macro-fractographic analysis of the fracture surface disclosed features that gave additional indication of fatigue. Examination of mating fracture surfaces under scanning electron microscope (SEM) detected the existence of irregularities in the material. Chemical analysis showed the aft cross tube is made of high-strength aluminum alloy. The stress analysis of skid landing gear, using the finite element method (FEM), has identified the stress-deformation condition of the helicopter landing gear with a detail insight of the stress state in the vicinity of the crack origin. The stress value, in case of maximal takeoff weight, was very high in the crack initiation zone. The results indicate the superposition of manufacturing-in, designing-in as well as operating in defects which led to total failure of the helicopter skid landing gear aft cross tube.
PB  - Elsevier
T2  - Engineering Failure Analysis
T1  - Fatigue fracture analysis of helicopter landing gear cross tube
VL  - 129
SP  - 105672
DO  - 10.1016/j.engfailanal.2021.105672
ER  - 

@article{
author = "Raković, Dragan and Simonović, Aleksandar and Grbović, Aleksandar and Radović, Ljubica and Vorkapić, Miloš and Krstić, Branimir",
year = "2021",
abstract = "This paper presents the failure analysis results of the helicopter skid landing gear. The helicopter skid landing gear fractured while the helicopter was on the ground at the airport. The aft cross tube of the landing gear assembly was found fractured into two pieces. Observation of crack propagation area at low magnification revealed numerous secondary cracks, inner surface irregularities while fracture surface indicated fatigue process. Macro-fractographic analysis of the fracture surface disclosed features that gave additional indication of fatigue. Examination of mating fracture surfaces under scanning electron microscope (SEM) detected the existence of irregularities in the material. Chemical analysis showed the aft cross tube is made of high-strength aluminum alloy. The stress analysis of skid landing gear, using the finite element method (FEM), has identified the stress-deformation condition of the helicopter landing gear with a detail insight of the stress state in the vicinity of the crack origin. The stress value, in case of maximal takeoff weight, was very high in the crack initiation zone. The results indicate the superposition of manufacturing-in, designing-in as well as operating in defects which led to total failure of the helicopter skid landing gear aft cross tube.",
publisher = "Elsevier",
journal = "Engineering Failure Analysis",
title = "Fatigue fracture analysis of helicopter landing gear cross tube",
volume = "129",
pages = "105672",
doi = "10.1016/j.engfailanal.2021.105672"
}

Raković, D., Simonović, A., Grbović, A., Radović, L., Vorkapić, M.,& Krstić, B.. (2021). Fatigue fracture analysis of helicopter landing gear cross tube. in Engineering Failure Analysis
Elsevier., 129, 105672.
https://doi.org/10.1016/j.engfailanal.2021.105672

Raković D, Simonović A, Grbović A, Radović L, Vorkapić M, Krstić B. Fatigue fracture analysis of helicopter landing gear cross tube. in Engineering Failure Analysis. 2021;129:105672.
doi:10.1016/j.engfailanal.2021.105672 .

Raković, Dragan, Simonović, Aleksandar, Grbović, Aleksandar, Radović, Ljubica, Vorkapić, Miloš, Krstić, Branimir, "Fatigue fracture analysis of helicopter landing gear cross tube" in Engineering Failure Analysis, 129 (2021):105672,
https://doi.org/10.1016/j.engfailanal.2021.105672 . .

TY  - JOUR
AU  - Vidanović, Nenad
AU  - Rašuo, Boško
AU  - Kastratović, Gordana
AU  - Grbović, Aleksandar
AU  - Puharić, Mirjana
AU  - Maksimović, Katarina
PY  - 2020
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4057
AB  - The main goal of this paper is to expand previously conducted study and consequently to upgrade the proposed multimodular numerical framework developed for fluid–structure interaction simulation (FSI) and multidisciplinary design optimization (MDO) purposes, in a manner that thermal–structure interaction is observed and implemented into the established numerical framework. The upgraded and considerably improved algorithm was used for MDO of the short-range ballistic missile (SRBM) model. Because of its high-speed regimes, this aircraft model was selected for the purpose of numerical modeling and optimization of aerodynamically heated structure. The present study is concerned with a broader observation of critical multipoint flight conditions and represents a more realistic scenario, which indicates this study as one contribution more in a scope of fluid–thermal–structure interaction (FTSI) numerical modeling and optimization. With respect to predefined objectives and constraints, multidisciplinary shape optimization of the fin structure resulted in overall improvement of the missile initial performances. Also, aerothermally induced critical responses of the fin structure were prevented. Numerical modeling of FSI/FTSI and MDO within an industry-accepted design tool resulted in powerful monolithic environment, which, with adopted multipoint regimes and multicriteria settings, was used for aerodynamic–thermal/structural optimization. The obtained results were compared with the results from the previous study conducted without thermal effects.
PB  - American Institute of Aeronautics and Astronautics
T2  - Journal of Spacecraft and Rockets
T1  - Multi-disciplinary Shape Optimization of Missile Fin Configuration Subject to Aerodynamic Heating
VL  - 57
IS  - 3
SP  - 510
EP  - 527
DO  - 10.2514/1.A34575
ER  - 

@article{
author = "Vidanović, Nenad and Rašuo, Boško and Kastratović, Gordana and Grbović, Aleksandar and Puharić, Mirjana and Maksimović, Katarina",
year = "2020",
abstract = "The main goal of this paper is to expand previously conducted study and consequently to upgrade the proposed multimodular numerical framework developed for fluid–structure interaction simulation (FSI) and multidisciplinary design optimization (MDO) purposes, in a manner that thermal–structure interaction is observed and implemented into the established numerical framework. The upgraded and considerably improved algorithm was used for MDO of the short-range ballistic missile (SRBM) model. Because of its high-speed regimes, this aircraft model was selected for the purpose of numerical modeling and optimization of aerodynamically heated structure. The present study is concerned with a broader observation of critical multipoint flight conditions and represents a more realistic scenario, which indicates this study as one contribution more in a scope of fluid–thermal–structure interaction (FTSI) numerical modeling and optimization. With respect to predefined objectives and constraints, multidisciplinary shape optimization of the fin structure resulted in overall improvement of the missile initial performances. Also, aerothermally induced critical responses of the fin structure were prevented. Numerical modeling of FSI/FTSI and MDO within an industry-accepted design tool resulted in powerful monolithic environment, which, with adopted multipoint regimes and multicriteria settings, was used for aerodynamic–thermal/structural optimization. The obtained results were compared with the results from the previous study conducted without thermal effects.",
publisher = "American Institute of Aeronautics and Astronautics",
journal = "Journal of Spacecraft and Rockets",
title = "Multi-disciplinary Shape Optimization of Missile Fin Configuration Subject to Aerodynamic Heating",
volume = "57",
number = "3",
pages = "510-527",
doi = "10.2514/1.A34575"
}

Vidanović, N., Rašuo, B., Kastratović, G., Grbović, A., Puharić, M.,& Maksimović, K.. (2020). Multi-disciplinary Shape Optimization of Missile Fin Configuration Subject to Aerodynamic Heating. in Journal of Spacecraft and Rockets
American Institute of Aeronautics and Astronautics., 57(3), 510-527.
https://doi.org/10.2514/1.A34575

Vidanović N, Rašuo B, Kastratović G, Grbović A, Puharić M, Maksimović K. Multi-disciplinary Shape Optimization of Missile Fin Configuration Subject to Aerodynamic Heating. in Journal of Spacecraft and Rockets. 2020;57(3):510-527.
doi:10.2514/1.A34575 .

Vidanović, Nenad, Rašuo, Boško, Kastratović, Gordana, Grbović, Aleksandar, Puharić, Mirjana, Maksimović, Katarina, "Multi-disciplinary Shape Optimization of Missile Fin Configuration Subject to Aerodynamic Heating" in Journal of Spacecraft and Rockets, 57, no. 3 (2020):510-527,
https://doi.org/10.2514/1.A34575 . .