Uncertainty Quantification

p3-25 January 23 14:50-15:50

Bayesian Inference of Grain Growth Prediction via Multi-Phase-Field Models

S. Ito(The University of Tokyo), H. Nagao(The University of Tokyo), T. Kasuya(The University of Tokyo), and J. Inoue(The University of Tokyo)

Abstract

We propose a Bayesian inference methodology to evaluate unobservable parameters involved in multi-phase-field models with the aim of accurately predicting the observed grain growth, such as in metals and alloys. This approach integrates models and a set of observational image data of grain structures. Since the set of image data is not a time series, directly applying conventional inference techniques that require time series as the input data is difficult. The key idea in our methodology to overcome this difficulty is to construct a time series with an appropriate statistic that characterizes static image data of grain structures. Our methodology implements the empirical Bayes method. It can estimate not only a probability density function of the parameters but also an initial phase-field, which is generally unobservable in real experiments. After validating the proposed method through numerical tests using synthetic data, we apply it to real experimental images of grain structures in a steel alloy. The proposed method properly estimates unobservable parameters together with their uncertainties, and successfully selects the initial phase-field that best explains the experimental data from among candidate initial phase-fields.

Contact information

Dr. Shin-ichi Ito The University of Tokyo