Two-way multi-scaling for predicting fatigue crack nucleation in titanium alloys using parametrically homogenized constitutive models

Ozturk, Deniz; Kotha, Shravan; Pilchak, Adam L.; Ghosh, Somnath

doi:10.1016/j.jmps.2019.04.009

Cited by 41 publications

(26 citation statements)

References 69 publications

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“…It is an extension of the PHCMs for polycrystalline α-phase Titanium alloys developed in refs. 1,6,7 . In this paper a class of dual-phase α/β Ti alloys containing a single variant of crystallographic orientation corresponding to parallel α/ β lamellae in each colony is considered.…”

Section: Discussionmentioning

confidence: 99%

“…statistical distributions of RAMPs, which are calculated from spatial variability of the microstructure in EBSD scans using a sampling method that has been discussed in ref. 7 . The resulting statistical moments of RAMPs from this sampling method are given in Table 2 and incorporated in the stochastic material evolution by the expansion-based UP method.…”

Section: Effect Of Microstructural Uncertainty On Mechanical Responsementioning

confidence: 99%

“…γ a is the accumulated plastic slip on all the bcc slip systems at a given point. Finally, a yield-point phenomenon is attributed to the resistance due to precipitate shearing τ α p on the basal and prismatic slip systems in hcp crystals, and is represented using the following relationship 7 .…”

Section: Crystal Plasticity Model For Dual Phase Titanium Alloysmentioning

confidence: 99%

“…PHCMs for polycrystalline α-phase titanium alloys have been developed in refs. 1,6,7 . The physics-informed PHCMs differ from conventional phenomenological models in their unambiguous depiction of constitutive parameters and their dependencies.…”

Section: Introductionmentioning

confidence: 99%

“…The PHCMs in refs. 1,6,7 enable full-scale component analysis with explicit representation of microstructural features and characteristics. They enjoy high accuracy, while being many orders of magnitude more efficient than conventional multiscale analysis methods.…”

Section: Introductionmentioning

confidence: 99%

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Uncertainty-quantified parametrically homogenized constitutive models (UQ-PHCMs) for dual-phase α/β titanium alloys

2020

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This paper develops an uncertainty-quantified parametrically homogenized constitutive model (UQ-PHCM) for dual-phase α/β titanium alloys such as Ti6242S. Their microstructures are characterized by primary α-grains consisting of hcp crystals and transformed β-grains consisting of alternating laths of α (hcp) and β (bcc) phases. The PHCMs bridge length-scales through explicit microstructural representation in structure-scale constitutive models. The forms of equations are chosen to reflect fundamental deformation characteristics such as anisotropy, length-scale dependent flow stresses, tension-compression asymmetry, strain-rate dependency, and cyclic hardening under reversed loading conditions. Constitutive coefficients are functions of representative aggregated microstructural parameters or RAMPs that represent distributions of crystallographic orientation and morphology. The functional forms are determined by machine learning tools operating on a data-set generated by crystal plasticity FE analysis. For the dual phase alloys, an equivalent PHCM is developed from a weighted averaging rule to obtain the equivalent material response from individual PHCM responses of primary α and transformed β phases. The PHCMs are readily incorporated in FE codes like ABAQUS through user-defined material modeling windows such as UMAT. Significantly reduced number of solution variables in the PHCM simulations compared to micromechanical models, make them several orders of magnitude more efficient, but with comparable accuracy. Bayesian inference along with a Taylor-expansion based uncertainty propagation method is employed to quantify and propagate different uncertainties in PHCM such as model reduction error, data sparsity error and microstructural uncertainty. Numerical examples demonstrate the accuracy of PHCM and the relative importance of different sources of uncertainty.

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Section: Discussionmentioning

confidence: 99%

Section: Effect Of Microstructural Uncertainty On Mechanical Responsementioning

confidence: 99%

Section: Crystal Plasticity Model For Dual Phase Titanium Alloysmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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