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Design of miniature specimens for calibration of ductile fracture criteria
Salvet, Patrik ; Vobejda, Radek (oponent) ; Šebek, František (vedoucí práce)
Numerical simulations have been rapidly progressing in recent years due to an increasing computational capacity. Finite element method has a great potential to partially replace and complement experiments, which are expensive, time consuming, and often difficult to perform. One of the major applications of numerical simulations is the prediction and simulation of material behavior. This thesis deals with the calibration and comparison of various phenomenological ductile fracture criteria dependent on stress triaxiality and third invariant of the deviatoric stress tensor, which can be implemented in finite element method to predict crack propagation. The ductile fracture criteria have been calibrated for aluminium alloy 2024-T351 using macroscopic samples. The calibration was done in MATLAB by approximating the calibration points with the ductile fracture criterion using the particle swarm optimization. Hookes’s law, a new recently proposed plasticity model, and an uncoupled ductile fracture model calibrated by the macroscopic samples have been implemented into Abaqus/Explicit to design four miniature specimens for an already designed tensile testing device. The designed miniature specimens capture various stress states in the fracture initiation zone, including uniaxial tension, shear stress, and plane strain. Based on a combination of experimental measurements and numerical simulations of these samples, the ductile fracture criteria can be calibrated to determine the suitability of miniature samples for the prediction of ductile fracture initiation and propagation.
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Design of miniature specimens for calibration of ductile fracture criteria
Salvet, Patrik ; Vobejda, Radek (oponent) ; Šebek, František (vedoucí práce)
Numerical simulations have been rapidly progressing in recent years due to an increasing computational capacity. Finite element method has a great potential to partially replace and complement experiments, which are expensive, time consuming, and often difficult to perform. One of the major applications of numerical simulations is the prediction and simulation of material behavior. This thesis deals with the calibration and comparison of various phenomenological ductile fracture criteria dependent on stress triaxiality and third invariant of the deviatoric stress tensor, which can be implemented in finite element method to predict crack propagation. The ductile fracture criteria have been calibrated for aluminium alloy 2024-T351 using macroscopic samples. The calibration was done in MATLAB by approximating the calibration points with the ductile fracture criterion using the particle swarm optimization. Hookes’s law, a new recently proposed plasticity model, and an uncoupled ductile fracture model calibrated by the macroscopic samples have been implemented into Abaqus/Explicit to design four miniature specimens for an already designed tensile testing device. The designed miniature specimens capture various stress states in the fracture initiation zone, including uniaxial tension, shear stress, and plane strain. Based on a combination of experimental measurements and numerical simulations of these samples, the ductile fracture criteria can be calibrated to determine the suitability of miniature samples for the prediction of ductile fracture initiation and propagation.
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