Dear Behzad,

There is no big difference between the two; both are members of the DEM approach. They provide slightly different functionality, particularly in the range of interaction laws supported

The Discrete Element Method (DEM) is the name assigned to a family of numerical modelling techniques which represent a material volume as a large number of indivisible particles (usually spheres) that interact via simple Newtonian forces. Wikipedia provides a very good introduction to the DEM:

http:// en.wikipedia. org/wiki/ Discrete_ element_ method

The LSM (and its derivative software LSMearth and ESyS-Particle) all implement the Discrete Element Method (DEM), as defined in the wikipedia page above. For reasons of simplicity we have restricted ourselves to dealing with spheres and simple bonded clusters of spheres rather than considering arbitrary particle shapes. We hope to extend ESyS-Particle to handle arbitrary particle shapes in the next few years.

The Discrete Element Method is a generic numerical method. Each software package that implements the DEM (e.g. TRUBAL, SDEM, EDEM, PFC3D, Yade, ESyS-Particle) tend to provide slightly different functionality, particularly in the range of interaction laws supported. ESyS-Particle provides a number of interaction laws for both bonded and unbonded interactions between spheres that may be either non-rotational, rotational, or rotational-thermal. The physics underlying these interaction laws has been motivated by the desire to simulate earthquakes, rock breakage and frictional granular media flow. Consequently the exact mathematical form of the interactions may differ somewhat to similar interaction laws in other DEM software.

1-A Review of Discrete Element Method (DEM) Particle Shapes and Size Distributions for Lunar Soil

NASA Technical Reports Server (NTRS)

Lane, John E.; Metzger, Philip T.; Wilkinson, R. Allen

2010-01-01

As part of ongoing efforts to develop models of lunar soil mechanics, this report reviews two topics that are important to discrete element method (DEM) modeling the behavior of soils (such as lunar soils): (1) methods of modeling particle shapes and (2) analytical representations of particle size distribution. The choice of particle shape complexity is driven primarily by opposing tradeoffs with total number of particles, computer memory, and total simulation computer processing time. The choice is also dependent on available DEM software capabilities. For example, PFC2D/PFC3D and EDEM support clustering of spheres; MIMES incorporates superquadric particle shapes; and BLOKS3D provides polyhedra shapes. Most commercial and custom DEM software supports some type of complex particle shape beyond the standard sphere. Convex polyhedra, clusters of spheres and single parametric particle shapes such as the ellipsoid, polyellipsoid, and superquadric, are all motivated by the desire to introduce asymmetry into the particle shape, as well as edges and corners, in order to better simulate actual granular particle shapes and behavior. An empirical particle size distribution (PSD) formula is shown to fit desert sand data from Bagnold. Particle size data of JSC-1a obtained from a fine particle analyzer at the NASA Kennedy Space Center is also fitted to a similar empirical PSD function.

Hoping this will be helpful,

Rafik

Dear Rafik, thanks for your information. Obviously our fields of research are significantly different. I am want to see for geotechnical application (stress transfer through soil) which software is easier to use and have more capabilities. 

Basically it depends what project you are modeling. From what I know,  PFC3D is suitable for Geotechnical problems, however not for complex geometry or combined structural analysis. I mean simple Triaxial modeling, oedometer, Steady and Transiant Flow are possbile, however complex modeling would take a lot of time when precision or particle size matters.

PFC is definitely more suitable for geotechnical problems. If you are looking for a open-source solution I would go with Yade. It has similar capabilities as PFC. Check out the link below, especially the list of publications. You might find something relevant to your research.

https://yade-dem.org

Dr. Behzad Fatahi , did you find an answer to the question you raised in 2015.

Please share, as I am new to start EDEM for my work, I would like to know from you.

Thanks