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Ductile Fracture Criteria in Multiaxial Loading – Theory, Experiments and Application
Šebek, František ; Horyl, Petr (oponent) ; Španiel, Miroslav (oponent) ; Petruška, Jindřich (vedoucí práce)
This thesis is concerned with ductile fracture, which is a result of multiaxial quasi-static monotonic loading accompanied with large plastic deformations, while the local approach is considered for material degradation. In computations, the damage evolution is governed by used ductile fracture criteria. These were theoretically studied in the introduction, and the calibration procedure was proposed after the choice of suitable fracture criterion. Next, the experimental program was designed, and the tests on aluminium alloy 2024-T351, concerning tension, torsion and compression, were realized at a room temperature for the investigation of damage accumulation and reliable calibration of chosen phenomenological ductile fracture criterion, expressed through the fracture strain, and dependent on the hydrostatic pressure and deviatoric stress tensor. The ductile fracture model was then coupled with the yield criterion. Plasticity was considered in the form of taking into account the state of third invariant of deviatoric stress tensor as well for investigated material. The whole proposed approach that is fully applicable to multiaxial problems was implemented using user subroutine into the commercial software, based on the explicit finite element method. In the end, the application of the proposed approach to modelling of ductile fracture is presented in the form of verification using chosen specimens, resulting in the conclusions and recommendations for future studies.
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Zbytková životnost pecí v petrochemickém průmyslu
Horsák, Libor ; Vincour, Dušan (oponent) ; Lukavský, Jiří (oponent) ; Vejvoda, Stanislav (vedoucí práce)
Tato práce se věnuje zbytkové životnosti pecí v petrochemické průmyslu. O této oblasti není k dispozici ucelená publikace. Je vyjmenována a popsána většina hlavních jevů, které je potřeba při určování životnosti zohlednit. Největší pozornost je věnována kumulaci poškození vlivem tečení materiálu (creep), na základě měření na konkrétní peci. Jsou zde popsány některé poruchy pecí, které by mohly způsobit neplánované přerušení provozu, avšak vhodným zásahem se podařilo pece udržet v bezpečném provozu až do plánovaného odstavení pece. Práce neposkytuje ucelenou metodu, jak v praxi dospět k určení zbytkové životnosti pece, ale naznačuje směr, jak by v budoucnu mohla vzniknout komplexní metoda hodnocení zbytkové životnosti pecí v petrochemickém průmyslu.
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Zbytková životnost pecí v petrochemickém průmyslu
Horsák, Libor ; Vincour, Dušan (oponent) ; Lukavský, Jiří (oponent) ; Vejvoda, Stanislav (vedoucí práce)
Tato práce se věnuje zbytkové životnosti pecí v petrochemické průmyslu. O této oblasti není k dispozici ucelená publikace. Je vyjmenována a popsána většina hlavních jevů, které je potřeba při určování životnosti zohlednit. Největší pozornost je věnována kumulaci poškození vlivem tečení materiálu (creep), na základě měření na konkrétní peci. Jsou zde popsány některé poruchy pecí, které by mohly způsobit neplánované přerušení provozu, avšak vhodným zásahem se podařilo pece udržet v bezpečném provozu až do plánovaného odstavení pece. Práce neposkytuje ucelenou metodu, jak v praxi dospět k určení zbytkové životnosti pece, ale naznačuje směr, jak by v budoucnu mohla vzniknout komplexní metoda hodnocení zbytkové životnosti pecí v petrochemickém průmyslu.
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Ductile Fracture Criteria in Multiaxial Loading – Theory, Experiments and Application
Šebek, František ; Horyl, Petr (oponent) ; Španiel, Miroslav (oponent) ; Petruška, Jindřich (vedoucí práce)
This thesis is concerned with ductile fracture, which is a result of multiaxial quasi-static monotonic loading accompanied with large plastic deformations, while the local approach is considered for material degradation. In computations, the damage evolution is governed by used ductile fracture criteria. These were theoretically studied in the introduction, and the calibration procedure was proposed after the choice of suitable fracture criterion. Next, the experimental program was designed, and the tests on aluminium alloy 2024-T351, concerning tension, torsion and compression, were realized at a room temperature for the investigation of damage accumulation and reliable calibration of chosen phenomenological ductile fracture criterion, expressed through the fracture strain, and dependent on the hydrostatic pressure and deviatoric stress tensor. The ductile fracture model was then coupled with the yield criterion. Plasticity was considered in the form of taking into account the state of third invariant of deviatoric stress tensor as well for investigated material. The whole proposed approach that is fully applicable to multiaxial problems was implemented using user subroutine into the commercial software, based on the explicit finite element method. In the end, the application of the proposed approach to modelling of ductile fracture is presented in the form of verification using chosen specimens, resulting in the conclusions and recommendations for future studies.
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Ductile fracture criteria in multiaxial loading – theory, experiments and application
Šebek, František ; Petruška, Jindřich (vedoucí práce)
This thesis is concerned with ductile fracture, which is a result of multiaxial quasi-static monotonic loading accompanied with large plastic deformations, while the local approach is considered for material degradation. In computations, the damage evolution is governed by used ductile fracture criteria. These were theoretically studied in the introduction, and the calibration procedure was proposed after the choice of suitable fracture criterion. Next, the experimental program was designed, and the tests on aluminium alloy 2024-T351, concerning tension, torsion and compression, were realized at a room temperature for the investigation of damage accumulation and reliable calibration of chosen phenomenological ductile fracture criterion, expressed through the fracture strain, and dependent on the hydrostatic pressure and deviatoric stress tensor. The ductile fracture model was then coupled with the yield criterion. Plasticity was considered in the form of taking into account the state of third invariant of deviatoric stress tensor as well for investigated material. The whole proposed approach that is fully applicable to multiaxial problems was implemented using user subroutine into the commercial software, based on the explicit finite element method. In the end, the application of the proposed approach to modelling of ductile fracture is presented in the form of verification using chosen specimens, resulting in the conclusions and recommendations for future studies.
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