Handling uncertainties in the development of tight-binding potentials : application to zirconium hydride
Résumé
In the field of material science for energy applications, zirconium hydrides are studied both for
their useful application for hydrogen storage and for their negative effect on mechanical properties
of the nuclear fuel cladding material (zirconium) in water cooled reactors. At the atomic scale,
the tight-binding (TB) approximation has proven to be a satisfying method to develop potentials
that are both accurate and computationally tractable to model zirconium hydrides. Such poten tials are defined by a fixed number of parameters that need to be accurately identified for the
model to be reliable. The reliability is indeed closely related to the uncertainties associated with
parameters [1]. Even if the use of parametric potentials, TB or semi-empirical ones, is widely es tablished in the literature [2], very few studies discuss the quantification of such uncertainties [3–5].
This work aims at quantifying the uncertainty associated with the calibration of TB poten tials. A previously developed TB potential [6]is used, focusing on its ability to reproduce elastic
constants and lattice parameters of δ (cubic) and (tetragonal) zirconium hydrides. Uncertainty
Quantification (UQ) methods, based on polynomial chaos expansion and Bayesian inference, are
used to estimate the parameters uncertainties, through their a posteriori probability distributions
and starting from a limited number of experimental and DFT data. The accuracy of the TB
potential - with respect to the available data - is thus improved. In addition, having characterized
the uncertainty on the model parameters, we can estimate the uncertainty propagation on any
computed property.
Domaines
Physique [physics]
Fichier principal
DelMasto_COSIRES_TB.PDF (110.17 Ko)
Télécharger le fichier
Poster_DelMasto_COSIRES22.pdf (1.62 Mo)
Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Licence : Copyright (Tous droits réservés)
Licence : Copyright (Tous droits réservés)
Licence : Copyright (Tous droits réservés)