Welcome

MechSys is a programming library for the implementation of simulation tools in mechanics. Its source code is mainly written in C++ with easier to use templates for further customization.

Potential applications include, for instance, solid mechanics and the dynamics of granular materials using the discrete element method, and both computational fluid dynamics and computational electromagnetics using the lattice Boltzmann method. For problems involving large deformations, a smooth particle hydrodynamics is also programmed to simulate fluids and soils at the continuum scale.

Discrete Element Method (DEM)

The Discrete Element Method is a powerful simulation scheme for soil, solid and fracture mechanics. Its fundamentals are simple, the body of study is divided in elements (could represent the individual grains in soils or pieces of solid in rocks) and Newton's laws are solve numerically to obtain their behaviour in time. Its popularity has grown in time since it reproduce naturally the elasto-plastic behaviour of soils and rocks and has many applications both in academy and industry. Mechsys DEM solver has the capability to deal with particles of general shape.

Lattice Boltzmann Method (LBM)

The Lattice Boltzmann Method was created to numerically solved the Boltzmann equation coming from statistical mechanics. It was shown that under some conditions it can also solve the Navier Stokes equations. Furthermore, it has proven to be a general Partial Differential Equation (PDE) solver. Mechsys has the traditional Navier Stokes solver module (LBM), a solver for Maxwell equations of electromagnetism (EMLBM) and the set of advection diffusion equations (ADLBM). As a novelty, Mechsys also couples DEM with LBM to have a powerful tool to simulate problems involving fluid and solid interaction.

Smooth Particle Hydrodynamics (SPH)

The Smooth Particle Hydrodynamics method was initially developed to solve Navier Stokes equations for fluids in situations involving large deformations and free surfaces. Later improvements have shown that SPH is also suitable to solve the constitutive equations of solids and soils. In Mechsys, SPH is coupled with DEM to produce simulation tools for problems such as debris flows and avalanches.

Acknowledgments

Mechsys development has been sponsored by the University of Queensland, the Australian Research Council (ARC Discovery Grant DP140100490 Qualitative and quantitative modelling of hydraulic fracturing of brittle materials) and the Advance Queensland Fellowship program (Grant AQ-15188 Pushing the boundaries of current numerical geotechnical modelling capabilities )

Examples

Some animations produced by MechSys' simulations are shown below. Additional animations can be found in Sergio Torres' Youtube channel for simulations created from Mechsys.

LBM Simulations

An imbibition-drainage simulation within a porous medium

A cavitation simulation where a fluid forms a liquid bubble

DEM Simulations

A triaxial test with general shaped particles

A brazilian test to determine the tensile strength of rocks

DEM+LBM Simulations

A DEM dolphin spinning and diving into an LBM pool

A simulation of the airblast hazard in block caving sites, the colormap represents the airspeed

EMLBM Simulations

A cross section area of a dipole antenna, both the electric (parallel to the plane) and the magnetic (perpendicular to the plane) fields are shown

An electric pulse (the electric field vector is going out from the screen) propagates between two media of different dielectric permittivity changing its speed and wavelength

SPH+DEM Simulations

A soil landslide simulated with SPH where the buildings are rigid structures represented by DEM particles

A debris flow simulation where the large boulders are represented by DEM and the mud with SPH

Featured publications

This is a selected list of scientific articles where Mechsys has been used.

 Pei Zhang, Siqi Sun, Yilin Chen, SA Galindo-Torres, Weicheng Cui (2021) Coupled material point Lattice Boltzmann method for modeling fluid-structure interactions with large deformations Computer Methods in Applied Mechanics and Engineering https://doi.org/10.1016/j.cma.2021.114040 Mario German Trujillo-Vela, Sergio Andres Galindo-Torres, Xue Zhang, Alfonso Mariano Ramos-Canon, Jorge Alberto Escobar-Vargas (2020) Smooth particle hydrodynamics and discrete element method coupling scheme for the simulation of debris flow Computers and Getechnics https://doi.org/10.1016/j.compgeo.2020.103669 CS From, E Sauret, SA Galindo-Torres, YT Gu (2020) Application of high-order lattice Boltzmann pseudopotential models Physical Review E https://doi.org/10.1103/PhysRevE.101.033303 CS From, E Sauret, SA Galindo-Torres, YT Gu (2019) Interaction pressure tensor on high-order lattice Boltzmann models for nonideal fluids Physical Review E https://doi.org/10.1103/PhysRevE.99.063318 Aminpour M, Galindo Torres S A, Scheuermann A, Li L (2018) Pore-Scale Behavior of Darcy Flow in Static and Dynamic Porous Media Physical Review Applied https://doi.org/10.1103/PhysRevApplied.9.064025 Li Z, Galindo Torres SA, Yan G, Scheuermann A, Li L (2018) A lattice Boltzmann investigation of steady-state fluid distribution, capillary pressure and relative permeability of a porous medium: Effects of fluid and geometrical properties Advances in Water Resources https://doi.org/10.1016/j.advwatres.2018.04.009 Galindo-Torres SA, Palma S, Quintero S, Scheuermann A, Zhang X, Krabbenhoft K, Ruest M, Finn D (2018) An airblast hazard simulation engine for block caving sites. International Journal of Rock Mechanics and Mining Sciences. https://doi.org/10.1016/j.ijrmms.2018.04.034 Li M, Xiao M, Zhang P, Hamilton DP (2018) Morphospecies-dependent disaggregation of colonies of the cyanobacterium: Microcystis under high turbulent mixing. Water Research. https://doi.org/10.1016/j.watres.2018.05.017 Zhiqiang C, Moran W (2017) Pore-scale modelling of hydro-mechanical coupled mechanics in hydro-fracturing process Journal of Geophysical Research http://dx.doi.org/10.1002/2017JB013989 Behraftar S, Galindo-Torres SA, Scheuermann A, Williams DJ, Marques EAG, Janjani H (2017) Validation of a novel discrete-based model for fracturing of brittle materials. Computers and Geotechnics, http://dx.doi.org/10.1016/j.compgeo.2016.08.029 Zhang P, Galindo-Torres SA, Tang H, Jin G, Scheuermann A, Li L (2016) Lattice Boltzmann simulations of settling behaviors of irregularly shaped particles Physical Review E. https://doi.org/10.1103/PhysRevE.93.062612 To H.D., Scheuermann A., Galindo-Torres SA (2016) Sequential sphere packing by trilateration equations. Granular Matter , http://dx.doi.org/10.1007/s10035-016-0666-5 Galindo-Torres SA, Scheuermann A, Li L (2015) Boundary effects on the Soil Water Characteristic Curves obtained from lattice Boltzmann simulations. Computers and Geotechnics, http://dx.doi.org/10.1016/j.compgeo.2015.09.008 Gerolymatou E, Galindo-Torres SA, Triantafyllidis T (2015) Numerical Investigation of the Effect of Preexisting Discontinuities on Hydraulic Stimulation. Computers and Geotechnics, http://dx.doi.org/10.1016/j.compgeo.2015.05.013 HMD Harshani, Galindo-Torres SA, Scheuermann A (2015) Micro-mechanical analysis on the onset of erosion in granular materials. Philosophical Magazine, http://dx.doi.org/10.1080/14786435.2015.1049237 To H.D., Scheuermann A., Galindo-Torres SA (2014) Primary fabric fraction analysis of granular soils. Acta Geotechnica Special Issue: Hydraulic instabilities in granular materials Theory and Experiments , http://dx.doi.org/10.1007/s11440-014-0353-9 Galindo-Torres SA, Scheuermann A, Williams DJ, Muhlhaus HB (2013) A micro-mechanical approach for the study of contact erosion. Acta Geotechnica Special Issue: Hydraulic instabilities in granular materials Theory and Experiments , dx.doi.org/10.1007/s11440-013-0282-z Galindo-Torres SA (2013) A coupled Discrete Element Lattice Boltzmann Method for the simulation of fluid-solid interaction with particles of general shapes Computer Methods in Applied Mechanics and Engineering , dx.doi.org/10.1016/j.cma.2013.06.004 Galindo-Torres SA, Pedroso DM, Williams DJ, Muhlhaus HB (2013) Strength of non-spherical particle assemblies under triaxial and shearing loading configurations. Granular Matter, dx.doi.org/10.1007/s10035-013-0428-6 Galindo-Torres SA, Scheuermann A, Li L, Pedroso DM, Williams DJ (2013) A lattice Boltzmann model for studying transient effects during imbibition-drainage cycles in unsaturated soils. Computer Physics Communications, 184(4), 1086-1093. dx.doi.org/10.1016/j.cpc.2012.11.015 Galindo-Torres SA, Scheuermann A, Li L (2012) A numerical study of the permeability in a tensorial form for laminar flow in anisotropic media. Physical Review E, 86, 046306. dx.doi.org/10.1103/PhysRevE.86.046306 Galindo-Torres SA, Pedroso DM, Williams DJ, Li L (2012) Breaking processes in three-dimensional bonded granular materials with general shapes. Computer Physics Communications, 183(2), 266-277. dx.doi.org/10.1016/j.cpc.2011.10.001 Galindo-Torres SA, Pedroso DM (2010) Molecular dynamics simulations of complex shaped particles using Voronoi-based spheropolyhedra. Physical Review E, 81, 061303. dx.doi.org/10.1103/PhysRevE.81.061303 Galindo-Torres SA, Marroquin F, Wang Y, Pedroso DM, Castano J (2009) Molecular dynamics simulation of complex particles in three dimensions and the study of friction due to nonconvexity. Physical Review E, 79, 060301. dx.doi.org/10.1103/PhysRevE.79.060301

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