Energy Dissipation and Wave Propagation in Fragmented Materials Under Dynamic Loading
Fragmented media are solids consisting of blocks, layers or other segments that are not cemented or glued to each other and for that reason have some freedom of relative movement. Fragmented materials include certain types of geomaterials, such as blocky and layered rock masses, stratified and fractured rocks. Further examples include mortarless structures, dry stone walls, interlocking structures and even rubble pile-type asteroids. Modelling wave propagation and energy dissipation in such materials is crucial for geophysics, resource industry, including space mining as well as condition monitoring of mortarless structures. The project investigates wave propagation and impact energy dissipation in systems of fragments. In order to investigate energy dissipation under dynamic loading we consider 3D arrangements of masses (fragments) connected by bi-linear springs with viscous/damping terms. The necessity to use extremely large numbers of fragments to adequately represent the mechanics and dynamics of the material puts high demand on the computer performance and hence requires the use of a HPC
Area of science
Energy and Resources
Systems used
Magnus
Applications used
MOOSE FrameworkThe Challenge
Wave propagation and energy dissipation in layered materials, one of the types of fragmented materials, with many thin layers is modelled using Cosserat continuum formulation which takes into account bending resistance of the layers. The mathematical formulation and fully developed constitutive equations are available, obtained in our previous research. As the Cosserat continuum involves additional degrees of freedom, the corresponding computations require considerable resources, which necessitates the use of a HPC.
The Solution
MOOSE Framework located on Magnus Supercomputer, Pawsey Centre, is the only software available on supercomputers that implements the Cosserat continuum equations and contains special libraries and source codes, which allows accounting for additional (rotational) DOFs for analysis of layered media under both static and dynamic loading.
The Outcome
With the help of Magnus Supercomputer, it was possible to 1) compare results of wave propagation in elastic media in MOOSE Framework and Abaqus in order to explore the discrepancies caused by the viscosity of differential scheme, see Fig. 1, and 2) investigate wave propagation in 2D Cosserat media with very fine mesh and adequately analyse energy transformation throughout the analysis and the emergence of different waves due to rotations of fragments, see Fig. 2-5.
List of Publications
Khudyakov, M., A. Dyskin and E. Pasternak, 2019. Analysis of energy dissipation during wave propagation in fragmented geomaterials by forced oscillations of a simple impact element. Geophysical Research Abstracts, Vol. 21, EGU2019-11526, EGU General Assembly 2019.
Figure 1. Graphs of wave profiles in elastic media after different simulation times in MOOSE and Abaqus
Figure 2. Y direction (up is positive) displacement field in a semi-indefinite a Cosserat medium for half sine kinematic excitation after 2 seconds of simulation
Figure 3. X direction (right is positive) displacement field in a semi-indefinite a Cosserat medium for half sine kinematic excitation after 2 seconds of simulation
