ASSESSING UNCERTAINTY IN CREEP LIFE OF GRADE 91 STEEL USING CRYSTAL PLASTICITY AND GRAIN BOUNDARY MICROSTRUCTURAL MODELS
Timothy TrusterDogwood A
This paper examines time to minimum creep rate and its uncertainty with respect to a set of fourteen material parameters. The microstructural model of Grade 91 steel includes both dislocation creep and grain boundary opening/sliding within a finite element model, and hence the simulations are relatively expensive and have several sources of nonlinearity. We will propagate uncertainty in the input material parameters of these two mechanisms and determine the aggregate uncertainty in the predicted time to minimum creep rate as well as the sensitivities of the parameters. The cost, stability, accuracy of the polynomial chaos expansion as a means for stochastic dimensional reduction is assessed against the classical Monte Carlo method.