b'HT9 ModelingPrincipal Investigator: Laurent CapolungoTeam Members/Collaborators: Andre Ruybalidhistory, (2) quantify the effects of varying microstructure on the statistics of performance (e.g., yield strength, minimum creep rate, swelling rate etc.)Empirical models fit to limited experimental data are unlikely to meet these requirements such that mechanistic constitutive laws are preferred. Further, from a pragmatic standpoint, constitutive models must be numerically efficient such as to enable utilization with finite element solvers (e.g., MOOSE). Unfortunately, while the literature offers a few advanced constitutive models for metals -and only one for HT9-, these cannot be seam-lessly introduced in MOOSE due to their computational burden. To Figure 1. Mean square relative errorT his task aims at developingaddress this limitation, this project maps for the output response of themodels for the mechanicalaims to develop and integrate a accumulated strain ss in the transientresponse of HT9 steels as asurrogate constitutive model for (top) and the steady-state (bottom)the mechanical response of HT9. regimes, for the surrogate model withfunction of its microstructure. The general idea is to generate emphasis on the transient regime Project Description: an extensive synthetic database Materials selection and qualificationmapping the response of the mate-for nuclear energy applicationsrial to its microstructure fingerprint entails that one can quantify theand then to mine the database to envelope of performance of compo- derive surrogate laws. The synthetic nents over their lifetime. Given thedatabase is generated via the use complexity of harsh environmentsof an advanced constitutive model to be encountered by the material,previously derived by the principal it is unlikely that decisions can beinvestigator (PI) and collaborators.made as to the viability of specificThe development of these surro-materials based on experiments/ gates and successful integration in tests alone. Therefore, models forfinite element solvers will enable the mechanical performance offor a quantification of the entire materials are needed. These predic- distributions of likely performance/tors must (i) be sufficiently generalresponse as a function of the fine to be applicable for arbitrary loading 154 2023|AFC ACCOMPLISHMENTS'