What You Can Simulate with Aspherix®

Some Highlights

Watch Aspherix® in action. These six DEM simulations show what particle simulation can do in real engineering work:

Particle Shapes

​Real particles are rarely round. Aspherix® supports a large variety of particle shapes, so pellets, grains, tablets, ore, fibers or agglomerates can be modelled with the shape that matches the material.

Use spheres, multisperes, superqudrics, convex or concave meshed particles or flexible / breakable agglomerates.

Physics Models

What makes a bulk material behave the way it does happens at the level of individual particles: how particles push, stick, rub and roll against each other, how they take up liquid, exchange heat or break apart. Aspherix® covers these effects with a large library of validated models.

The contact models range from classic Hertz and Hooke formulations to elasto-plastic, adhesive and time- or temperature-dependent variants, with several rolling friction models on top. Cohesive and wet materials are handled by JKR and SJKR cohesion, powder models and liquid bridges that form, transport liquid, evaporate and solidify, from spray coating to agglomeration. Heat conduction, radiation, melting and mass transfer describe thermal and chemical processes, while bond models make it possible to simulate flexible fibers and breakable agglomerates. Attrition and equipment wear show what happens to the product and the machine over time. Electrostatic charging, electrical conductivity and magnetic forces complete the range.

Every model is ready to combine with any other, so the simulation reflects the material, not the limits of the software. Browse the detailed model overview below.

Scalability & Speed

Industrial processes involve millions of particles, complex geometries and long process times, and results are still needed quickly. Aspherix® is built to handle this, from a desktop workstation to a large HPC cluster or the cloud, with no change to the simulation setup. You typically set up the case in the GUI and then send it to the cluster for computation.

On CPUs, standard MPI parallelization has shown near-linear scaling up to 1,000 cores and 100 million particles. Dynamic load balancing keeps all cores busy even when the particles fill only a small, moving part of the domain. On NVIDIA GPUs, a single graphics card matches or beats 64 CPU cores for cases above roughly 500,000 particles. Independent benchmarks found Aspherix® about 3× faster than its predecessor LIGGGHTS® on CPU. This makes industrial-scale simulations practical in everyday engineering work.

Coarse-graining represents groups of particles as larger parcels while keeping the bulk behavior. Scaling laws are applied automatically to contacts, cohesion, drag and heat and mass exchange, so no manual re-tuning is needed. Dynamic coarsening and refinement put detail only where it matters, saving up to 8× in computing effort in a Wurster coater.

Postprocessing

A simulation is only as valuable as the insight it delivers. Pictures of moving particles are a good start, but process decisions need numbers: How well is the powder mixed? How long does the material stay in the drum? Where are the highest loads on the equipment? Aspherix® answers these questions with evaluations built into the software, set up alongside the simulation in the GUI and calculated while it runs.

Particle data can be averaged in space and time, summarized as mixing indices, mass flows and centers of mass, or evaluated in cross-sections and Voronoi cells. Residence time and residence distance distributions show how material moves through the process. Contact and bond networks, stress tensors and wall loads reveal the forces inside the bulk and on the equipment, while collision statistics and the energy balance explain where energy is put in and dissipated. Steady-state detection tells you when the results are ready to use, and evaluations can also be repeated on finished simulations.

All results are written as CSV and VTK files for graphs and animated playback, including in ParaView with a dedicated Aspherix® macro. This turns raw particle data into answers you can act on.

Coupling Interfaces

Particles rarely act alone. They are carried by gas flows, load and deform structures, interact with moving machine parts and respond to electric fields. Many of these effects can be modelled directly in Aspherix®, but some need dedicated software. For these, Aspherix® comes with ready-made interfaces to other simulation tools.

With our particle fluid software CFDEM®coupling particles and fluid are fully coupled in both directions, including heat and species transport and reactive multiphase flows. The coupling with the Elmer FEM solver passes particle loads to a structure and sends the resulting deformation back to the DEM simulation. Through the FMI standard, a multibody dynamics code such as Simulink/Simscape or MSC Adams moves the DEM geometries and receives the particle forces and torques in return. Electrostatic forces act on charged particles, with optional charge transfer when they collide.

By combining Aspherix® with these specialised tools, you can simulate the whole process, including flow, structure, machine and field effects, not just the particles.

C++ / Python API

Aspherix® can do more than run standalone simulations: you can also drive it from your own code. The C++ and Python APIs let you embed the DEM solver in your own applications and workflows, run input files or single commands from a script, and control a simulation step by step. You can read and change particle, contact, mesh and simulation data directly, without going through files.

For special physics, you can add your own contact models and custom commands through the API. This lets you run parameter studies, optimisation loops, use Aspherix® as the DEM part of a larger simulation chain, or connect it to your own tools.