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Title: Calibrating the stress-time curve of a combined finite-discrete element method to a Split Hopkinson Pressure Bar experiment

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.

Authors:
 [1];  [1];  [1];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE; LANL Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1435489
Alternate Identifier(s):
OSTI ID: 1438151
Report Number(s):
LA-UR-18-22744
Journal ID: ISSN 1365-1609
Grant/Contract Number:  
AC52-06NA25396
Resource Type:
Journal Article: Published Article
Journal Name:
International Journal of Rock Mechanics and Mining Sciences
Additional Journal Information:
Journal Volume: 106; Journal ID: ISSN 1365-1609
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
97 MATHEMATICS AND COMPUTING; Computer Science; Mathematics; Material Science

Citation Formats

Osthus, Dave, Godinez, Humberto C., Rougier, Esteban, and Srinivasan, Gowri. Calibrating the stress-time curve of a combined finite-discrete element method to a Split Hopkinson Pressure Bar experiment. United States: N. p., 2018. Web. doi:10.1016/j.ijrmms.2018.03.016.
Osthus, Dave, Godinez, Humberto C., Rougier, Esteban, & Srinivasan, Gowri. Calibrating the stress-time curve of a combined finite-discrete element method to a Split Hopkinson Pressure Bar experiment. United States. doi:10.1016/j.ijrmms.2018.03.016.
Osthus, Dave, Godinez, Humberto C., Rougier, Esteban, and Srinivasan, Gowri. Tue . "Calibrating the stress-time curve of a combined finite-discrete element method to a Split Hopkinson Pressure Bar experiment". United States. doi:10.1016/j.ijrmms.2018.03.016.
@article{osti_1435489,
title = {Calibrating the stress-time curve of a combined finite-discrete element method to a Split Hopkinson Pressure Bar experiment},
author = {Osthus, Dave and Godinez, Humberto C. and Rougier, Esteban and Srinivasan, Gowri},
abstractNote = {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 σtmax and to a lesser extent maximum tensile strength σnmax govern the behavior of the stress-time curve before and around the peak, while the specific energy in Mode II (shear) Et 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.},
doi = {10.1016/j.ijrmms.2018.03.016},
journal = {International Journal of Rock Mechanics and Mining Sciences},
number = ,
volume = 106,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2018},
month = {Tue May 01 00:00:00 EDT 2018}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.ijrmms.2018.03.016

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