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Ansys Rocky
Particle Dynamics Simulation Software

Ansys Rocky is the industry-leading discrete element method (DEM) software used for simulating the motion of granular and discontinuous material.  

Quickly and Accurately Simulate Particle Flows

Rocky is designed to solve engineering problems. Rocky is uniquely capable to models real particle shapes including any solids, 2D shells, and rigid and flexible fibers. The simulations are fast and accurate. With multi-graphics processing unit (GPU) solver technology, you can simulate the behavior of different shaped and sized particles in many industrial applications.

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    Multi- GPU Solver
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    Scalable, efficient, large particle counts
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    Realistic Particle Shapes including fibers
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    Wear modeling, particle breakage, cohesion

Accelerate your toughest particle simulations by using the most powerful DEM software in the market. Ansys Rocky contains industry leading features and capabilities to solve large, complex problems accurately and efficiently.

Custom Fitting a Solution for Kitchen Appliances

Using DEM to design a more robust heat exchanger


Compared to bench-top component-level testing, overall foulant simulation can produce savings of up to 10% of total development costs — along with reduced time to market, since results are available in a week, compared to months.

Read Article

Built-in appliances fill today’s high-end kitchens, in which seamless integration with cabinetry can pose technical challenges related to airflow restriction in a machine’s compartment. This problem is exacerbated by dirt accumulation on the condenser (heat exchanger), which can affect appliance performance.

Experimental evaluation of dirt accumulation on condensers is time-consuming and expensive. Consequently, Sub-Zero is coupling Ansys Fluent computational fluid dynamics (CFD) and Ansys Rocky discrete element modeling (DEM) to quickly gain insight on the mechanisms behind dirt accumulation in an effort to design a more robust heat exchanger.

January 2024

What's New

In 2024 R1, Ansys Rocky continues to address customers' needs, delivering features that enable users to perform DEM (Discrete Element Method) simulations, keeping the focus on multiphysics, providing new SPH (Smoothed Particle Hydrodynamic) capabilities, and optimizing user experience, allowing limitless possibilities on particle dynamics simulation. 


Perform DEM simulations leveraging new enhancements, including thermal coupling with Ansys Mechanical, particle transparency analysis, and liquid bridge compatibility with course graining.

Enhanced SPH Capabilities

Enhanced SPH capabilities enable faster simulation by gaining performance with the new incompressible SPH (iSPH) algorithm, new viscosity models for non-Newtonian fluids simulation, SPH 1-way coupling with Ansys Fluent and Heat Transfer Coefficient (HTC) without requiring a thermal solution.

User Experience & Developer Ecosystem

Automation and flexibility with PyRocky, a new user interface with style standardization and the dark theme, Rocky documentation under Ansys Help, and AIS Rocky are one place for self-learning and community interaction.


Solve the Largest, Most Complex Particle Simulations With Ease

Ansys Rocky unlocks the potential of solving the most challenging DEM simulations. Large scale simulations, going up to millions of particles, can be solved using real particle shapes on multi GPU’s.



Key Features

Rocky is the premier tool for quickly and accurately simulating the behavior of bulk materials with complex particle shapes and size distributions.

  • Multi-GPU Processing
  • Realistic, Complex Particle Shapes
  • Fluids Coupling
  • Structural Mechanics Coupling
  • Electromagnetic Coupling
  • Multibody Dynamics
  • Breakage Modeling
  • Smoothed-Particle Hydrodynamics

The multi-GPU solver in Rocky distributes and manages the combined memory of two or more GPU cards within a single motherboard, overcoming memory limitations and achieving a substantial performance increase by aggregating computing power. Rocky can speed up your particle simulations and help facilitate large-scale simulations involving tens of millions of particles.

Rocky enables you to simulate a system with real particle shapes and sizes, specifying both spherical and truly non-spherical particle shapes, including shells and fibers. You can set up particle groups with particle size distributions and mix simulations of different particle shapes. Rocky comes with default shapes that you can use out-of-the-box or modify to match your particles. You can also define and import your own custom shapes. Fiber particles in Rocky can be of any length, flexible or rigid, and can be breakable. 

Engineers need to assess to interaction of fluid and particles in many applications.  Rocky coupled with Ansys Fluent creates a powerful workflow for modeling fluid systems.  Specially for non-spherical particles or for systems with particle size distribution, engineers can create a multiphysics simulation by coupling CFD and DEM. CFD-DEM coupling can be used in two different ways:

  • When the fluid field affects the particle flow, but the particles don’t affect the fluid flow
  • When the fluid flow affects the motion of particles and the particles in turn affect the motion of the fluid

Coupling DEM with FEA, engineers can simulate transient cases while incorporating geometry motion and time-varying loads on boundary elements.

During simulation, Rocky tracks the loads on each node of a geometry mesh. These loads are then exported as a pressure field for further analysis with Ansys Mechanical. The FEA software then discretizes the geometry and solves for the equilibrium conditions.

Rocky enables solutions of particle flow affected by electromagnetic fields by coupling with Ansys Maxwell.  Electric particles can experience three types of phenomena, with particles being influenced by electromagnetic fields, electrostatic fields or tribocharging.  The magnetic fields calculated by EM solvers are imported as point clouds into Rocky. The resulting calculations show the particle flow, including particle attraction depending on the charge. 

Rocky gives you the freedom to configure complex geometry movements by enabling as many translational, rotational, vibrational, swinging, crushing and free-body motions as you need. The fully integrated motion kernel offers support for combined geometry motions within the software.

Whether you want to prescribe exact movements or have your geometry components move freely in response to outside forces like particle contacts and gravity, Rocky has your complex motion needs covered. For more complex motions with that combine the effects of loads and mechanics, Rocky can be coupled to Ansys Motion. 

Rocky’s unique, discrete breakage model is a high-fidelity model that considers the collision location at the particle’s surface along with its consequent internal stresses, capturing shape-dependent breakage and crack propagation.

Unlike most DEM codes that use a combination of spheres connected to each other to approximate a particle shape, Rocky uses tetrahedra, allowing for representation of any particle shape while preserving volume and mass. Thus, it can simulate breakage for particles of any shape and aspect ratio: fibers, shells and custom-shaped particles.

The SPH (Smoothed-Particle Hydrodynamics) is a method to model fluids in fluid-particle simulations. This Lagrangian mesh-free method helps account for the fluid effect on particles in problems with high solid content and free surface flows.​

Powered by a computationally efficient GPU-based solver, SPH is fully integrated into Rocky UI.

Featured Webinars

Webinar Series
Rocky DEM Webinar
Ansys Rocky Webinar Series

This webinar series features 15-minute demonstrations showcasing how Rocky can be used to solve some of your most challenging particle simulations. 

Webinar On Demand
Ansys 2024 R1: Ansys Rocky What’s New

Join us for this webinar to discover all the new features in Ansys Rocky in the 2024 R1 release, including improved DEM, enhanced SPH, and the new user interface.

Webinars on Demand

Ansys software is accessible

It's vital to Ansys that all users, including those with disabilities, can access our products. As such, we endeavor to follow accessibility requirements based on the US Access Board (Section 508), Web Content Accessibility Guidelines (WCAG), and the current format of the Voluntary Product Accessibility Template (VPAT).

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