Global ETD Search
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Showing 1 to 15 of 15 for “"Stress triaxiality"”.
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Deformation and fracture of polycarbonate and rubber-modified polycarbonate under controlled temperature, deformation rate, and notch stress triaxiality
… effects of strain rate, temperature, and notch stress triaxiality on deformation and fracture are studied. The Arruda-Boyce constitutive model for glassy polymers and finite element simulations are used to simulate the deformation of the polycarbonate homopolymer subjected to compression and …
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Prediction of ductile crack formation in uncracked bodies
… of different weighting functions for different stress triaxiality ranges where different ductile crack formation mechanisms occur ("shear fracture" in negative stress triaxialities, void nucleation, growth, and linkage in high stress triaxialities, a transition mode in intermediate stress …
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Experimental investigation and constitutive modeling of the large deformation behavior of anisotropic steel sheets undergoing strain-induced phase transformation
… The experimental program for different stress states includes experiments for uniaxial tension, uniaxial compression, equi-biaxial tension, pure shear, and transverse plane strain tension. The resulting experimental data demonstrate the influence of both the stress triaxiality and Lode …
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Micromechanics of Hydrogen-Induced Crack Initiation in Pipeline Steels and Subcritical Crack Growth
… we quantify the void growth dependence on stress triaxiality and hydrogen-induced material softening as a function of position ahead of a crack tip. Correlation of the calculated void diameters with experimentally measured ones leads to the identification of a microstructural length that …
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Effects of prior ductile tearing on cleavage fracture in the ductile-to-brittle transition region
… surfaces which relaxes crack-tip constraint (stress triaxiality). In the mid-to-upper transition region, small amounts of ductile crack extension (typically $<$1-2 mm) routinely precede termination of the ${J-\Delta a}$ curve by brittle fracture. Large-scale yielding, coupled with small …
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Investigation of Taylor impact test of isotropic and anisotropic material through geometrical characteristics of specimens
… the plastic distributions and the dynamic yield stresses of specimens. A raise in yield strength is found in the copper alloy during the impact. It means that material properties of the copper alloy are sensitive to high strain rate. Yet such phenomenon is not found in the 2195-T8 …
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Fracture prediction in metal sheets
… accumulated equivalent plastic strain with the stress triaxiality as a weighting function is considered. Using the equations of plane stress von-Mises plasticity and the strain-to-stress mapping procedure, the BW fracture criterion is transformed to the spaces of the principal tensile strains …
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Development of a punching technique for ductile fracture testing over a wide range of stress states and strain rates
… shown that the dependence of ductility on the stress triaxiality and Lode parameter must be accounted for, but this dependence has not been investigated in the dynamic range. The aim of the current thesis is to contribute a new methodology based on an instrumented drop tower that will allow for …
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Micromechanical modeling of the toughening mechanisms in particle-modified semicrystalline polymers
… of filler particles and the level of applied stress triaxiality. In particular it is shown, that in the case where transcrystallized material spans the interparticle ligaments, the unique morphology of the matrix impedes dilatational expansion of the material, while promoting ...
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Effect of loading history in necking and fracture
… of Lode angle parameter, or the third deviatoric stress invariant, on plasticity and fracture is studied using flat-grooved transverse plane strain specimens. A generalized asymmetric plasticity model for isotropic materials with both pressure and Lode angle dependence is developed. Calibration …
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Edge fracture of AHSS sheets under out-of-plane loading followed by in-plane loading
… locus description with dependence on both stress triaxiality and Lode angle parameter. The proposed model successfully predict edge fracture in numerical simulation.
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Ductile fracture at intermediate stress triaxialities : experimental investigations and micro-mechanical modeling
… a comprehensive investigation into the effect of stress state on the onset of ductile fracture of an Advanced High Strength Steel (AHSS), covering development of new experimental procedures, material characterization and phenomenological as well as micro-mechanical modeling of the onset of …
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Ductile fracture after complex loading histories : experimental investigation and constitutive modeling
… the linear combination of the Hosford equivalent stress and the normal stress acting on the plane of maximum shear reaches a critical value. A comprehensive fracture initiation model is then obtained after transforming the localization criterion from the stress space to the space of equivalent …
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Chemomechanical modeling of hydrogen-induced degradation at high temperatures
… and the operating conditions, e.g., applied stress level and time. The API publication presents a series of Nelson curves specific to various steel compositions that are used extensively in the refining and petrochemical industries. These curves establish the safe operation regimes in a …
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Deformation and residual stresses at the intragranular scale – a study using high energy x-ray diffraction and modeling in polycrystalline alloys
Deformation and internal stress distribution in polycrystalline materials depend upon interactions among neighboring grains and sub-grains (substructure inside a grain). With the advent of high energy x-ray diffraction (HEXD), using synchrotron radiation, it has become possible to probe the bulk of …