Lecture "Discrete element method for modeling wave propagation in dry and saturated granular media"

PhD Hongyang Cheng from the University of Twente (NL) delivers the lecture "Discrete element method for modeling wave propagation in dry and saturated granular media". The students and researchers are invited on Tuesday, the 11th of September, at 10:30 am, room F of the DST.
 
Abstract
The Discrete Element Method (DEM) captures the collective behavior of a granular material by tracking the kinematics of the constituent grains. DEM simulations using measured particle configurations as input, e.g., from X-ray imaging, allows for a micromechanical interpretation on the acoustic response of a given granular system. This talk covers the fundamentals of DEM and the applications to wave propagation in dry and saturated granular media. For the calibration of DEM models, we use an iterative Bayesian filtering approach to infer the posterior probability distribution of grain properties, conditioned to experimental data. Once calibrated, time and frequency domain techniques can be applied to investigate the acoustic properties such as dispersion relations. The numerical modeling of wave propagation in saturated granular media requires a coupling of hydrodynamics with particle motion. The coupling scheme is briefly presented and its powerful capability shown in the comparison with Biot's analytical solution of wave velocities in saturated granular-elastic media.
 
Short biography
Dr. Cheng is a postdoc in the Multi-Scale Mechanics group of Prof. Stefan Luding at the University of Twente (UT). Before joining the UT, he worked on multiscale characterization of structured/nonstructured fibre-soil mixtures at Hiroshima University, Japan. During his PhD, he initiated an independent research line on Bayesian uncertainty quantification in discrete element method (DEM) simulations of granular media. He developed a Bayesian calibration toolbox GrainLearning for the open-source DEM package YADE, which allows the inference of grain properties from macroscopic measurements. Within the Bayesian framework, his research now focuses on wave propagation in dry and saturated granular media, using coupled numerical methods (DEM/FEM/LBM).
 
Only for the students of the Master Course in Exploration and Applied Geophysics, participating to the lecture will contribute to obtain cfu for the "Other Activities".