Calibrating the stress-time curve of a combined finite-discrete element method to a Split Hopkinson Pressure Bar experiment. (June 2018)

• Record Type: Journal Article
• Authors: Osthus, Dave; Godinez, Humberto C.; Rougier, Esteban; Srinivasan, Gowri
• Is Part Of: International journal of rock mechanics and mining sciences. Volume 106(2018)
• Page Start: 278
• Page End: 288
• Publication Date: 2018-06
• Subjects: Combined finite-discrete element method -- Split-Hopkinson pressure bar -- Probabilistic calibration; Rock mechanics -- Periodicals; Soil mechanics -- Periodicals; Mining engineering -- Periodicals; Roches, Mécanique des -- Périodiques; Sols, Mécanique des -- Périodiques; Technique minière -- Périodiques; 624.151305
• DOI: 10.1016/j.ijrmms.2018.03.016
• Languages: English
• ISSNs: 1365-1609

Abstract

Abstract: We present a generic method for automatically calibrating a computer code to an experiment, with uncertainty, for a given "training" set of computer code runs. The calibration technique is general and probabilistic, meaning the calibration uncertainty is represented in the form of a probability distribution. We demonstrate the calibration method by calibrating a combined Finite-Discrete Element Method (FDEM) to a Split Hopkinson Pressure Bar (SHPB) experiment with a granite sample. The probabilistic calibration method combines runs of a FDEM computer simulation for a range of "training" settings and experimental uncertainty to develop a statistical emulator. The process allows for calibration of input parameters and produces output quantities with uncertainty estimates for settings where simulation results are desired. Input calibration and FDEM fitted results are presented. We find that the maximum shear strength σ t max and to a lesser extent maximum tensile strength σ n max govern the behavior of the stress-time curve before and around the peak, while the specific energy in Mode II (shear) E t largely governs the post-peak behavior of the stress-time curve. Good agreement is found between the calibrated FDEM and the SHPB experiment. Interestingly, we find the SHPB experiment to be rather uninformative for calibrating the softening-curve shape parameters ( a, b, and c ). This work stands as a successful demonstration of how a general probabilistic calibration framework can automatically calibrate FDEM parameters to an experiment.