Altair EDEM Professional 2021.2.0

CUDA Engine for Multi-Sphere Particles
The CUDA solver engine within EDEM has been expanded to handle more particle types. The previous GPU solver is now known as the GPU OpenCL Solver where the new one is referred to as the GPU CUDA solver.
The new simulator engine has been proven to give significant performance benefits especially in scenarios where the simulations include particle factories.The Multi-Sphere solver supports the majority of the EDEM contact models (see chart in Known Issues) section.
The new solver is written in NVIDIA CUDA 11.0® and designed for high performancecards.
Sphero-Cylindrical Particles
EDEM 2021.2 introduces a new Sphero-Cylinder particle shape solver that runs on EDEM CUDA solver. Sphero-Cylinder particle shapes can be created in the EDEM Creator. The materials can have size distributions allowing for the real-world variation in materials.
Sphero-Cylindrical particles eliminate the “raspberry effect” when simulating long particles and the rounded ends of Sphero-Cylinders simplifies particle contact detection to reduce computational expense. The Sphero-Cylindrical particles are best suited to simulations involving long thin particles such as agricultural materials like grass and straw.
The Sphero-Cylinder solver supports all of the contact models available on the CUDA Multi-Sphere engine.
The Sphero-Cylinder solver can be used with EDEM’s coupling interface for coupled simulations with CFD, MBD and custom scripts.

Additional Enhancements

Creator

Import and Export of Polyhedral and Sphero-Cylinder particles
Polyhedral and Sphero-Cylindrical particles can be exported and imported between simulation decks. This allows for simulations to be quickly set up using the same particles. The option for importing or exporting a particle is available from the right click menu with a particle or bulk material selected.
Geometry Import Options
The geometry import mesh options now use the length and angle unit defined in the Options Menu. The default values for the meshing options have been modified to be appropriate for the unit being used. This will allow greater control over the imported mesh and a greater chance of successfully importing geometries without needing to modify mesh values.
The mesh options for characteristic length are not affected by the unit change, however the max deviation is now also expressed relative to characteristic length.This will produce better meshes for certain shapes such as pipes and tubes.
Refresh button in Plug-in Factory interface
A refresh button has been added to the plug-in factory settings. This allows the model to be updated and refreshed without the need to delete and reload the custom factory.
Edinburgh Elasto-Plastic Adhesion Parameter Estimator parameter names
The EEPA Parameter Estimator introduced in EDEM 2021.1 has been updated to new labels for the outputs to ensure better understanding of the values

Simulator

EDEM Command Line parameters
The command line output has been updated to include headings for the output parameters. The number of parameters has been reduced to avoid confusion.
Linear Periodic Boundary conditions for CUDA solvers
The CUDA solver now supports periodic boundaries. This includes the new MultiSphere and Sphero-Cylinder solvers, as well as the existing Polyhedral solver. This allows users to simulate using fewer particles under suitable conditions leading to faster simulations and easier post-processing.
Double, Hybrid and Single Precision for CUDA solvers
The CUDA solvers in EDEM have the option of selecting the precision of floating-point numbers used to represent variables in the simulation. There are 3 options available:

- Double Precision: All simulation variables are represented using double precision. This option gives maximum accuracy and is consistent with the approach taken by the existing EDEM solvers.
- Hybrid Precision: The simulation variables are represented using a combination of single and double precision where necessary. This option provides a balance between faster solver speed whilst retaining numerical accuracy.
- Single Precision: All simulation variables are represented using single precision. This option is the fastest to run but has reduced accuracy compared to double precision and is not suitable for all applications.

The Double Precision option is most consistent with the solvers used in previous versions of EDEM, however the Hybrid Precision has shown to significantly improve simulation runtime without compromising accuracy.
Rolling Friction Model 'Type C'
A new Type C rolling friction model has been added to EDEM. This model goes beyond the standard EDEM rolling friction model by including a non-viscous term in the damping torque equations. The use of this model may result in a more accurate behavior and greater stability.

Analyst

Export geometry from EDEM to STL
The ability to export geometries from a simulation has been added to the Analyst.This allows geometries to be exported at any time step of the simulation and will account for the updated position of the geometry as a result of the kinematics and motions used in the simulation. Note, changes to the geometry as a result of deformation are not included.
Export particles from EDEM to STL
The ability to export particles from a simulation has been added to the Analyst. This feature generates a CAD file containing a mesh per particle for a single timestep. The fidelity of the mesh can be selected at the time of export. Currently this functionality is only compatible with Multi-Sphere particles. Exported particles can be used in other simulators such as CFD and in rendering packages.
Line Graph the default tab in the Analyst
The default tab for graphing is now the line graph. This is based on customer feedback that this would help speed up user workflow.
Particle Streams display performance improved
The speed of using the stream view for simulations has been significantly improved.This is particularly apparent when using large numbers of particles and selections.
Allow field data to be colored in 5/7/9 colors
Field Data in the Analyst can be colored with up to 9 color levels.
Running EDEMpy scripts from the Analyst
EDEMpy scripts can be run from within the Analyst. Python is included in the installer and the current EDEMpy library (v0.1.5) is set up during the installation. Users can select a python script and pass additional arguments for the script.

EDEM API

Support backward compatibility for CUDA API versions-from 2021.2 onwards
The EDEM API version has been incremented from V3.1 to V3.3 and introducessignificant changes to the CUDA API. The input parameters for both calculateForce and externalForce have been simplified to have fewer, more consistent, class structures. Object information is now retrieved and adjusted using a range of "getter" and "setter" functions.
These changes to the CUDA API result in the V3.1 APIs being incompatible with EDEM 2021.2 onwards. However, the updates to the structure of the CUDA API V3.3 ensures backwards compatibility going forwards and accommodates the expanded particle range of the CUDA solver.

Coupling Interface

Coupling Interface flags to enable functionality before simulation
A series of initialization flags have been added to the Coupling Interface. These flags allow users to predefine what functionality the coupling script will use. This will improve simulation performance by removing unnecessary calculation and data transfer. The current list of flags can be found in the CCouplingFeatureFlags class in ApiTypes.h. Older coupling scripts written prior to this functionality will run without the flags being defined, however they will not benefit from the performance improvement.
Consistent naming for Coupling Interface functions
Certain Coupling Interface functions have been created for improved consistency.These functions will now have names in line with other functions, the new functions are:

- getGeometryNames (formerly getGeometrySectionNames)
- setGeometryMaterial (formerly setSectionMaterial)

The setSectionMaterial and getGeometrySectionNames are now deprecated. They will still function if used but will be considered for removal in the future
Consistent Coupling Interface inputs for Geometry
Certain Coupling Interface functions have been updated for improved consistency and performance. These functions can now make use of geometry ID rather than the geometry section name as a string. The functions affected are:

- getGeometryType
- removeGeometry
- renameGeometrySection
- setGeometryType
- setTransformParent

A new function getGeometryIDs has been added to complement this change.
setScales and setPositions functions added which take arrays instead of single values
Two new functions have been added to the Coupling Interface: setScales and setPostions. These are similar to the setScale and setPosition functions, however these accept arrays rather than single values. This will allow these functions to act in a more consistent way to other Coupling Interface functions, setting the scale and position of multiple particles in one function call.

Physics

Experimental Cohesion model for Polyhedral Particles
A contact model has been added to the experimental contact models. This is a cohesion model for Polyhedral particles. This model is partially based on the JKR contact model used with Multi-Sphere and Sphero-Cylinder particles. This model is available for both particle-particle interaction and particle-geometry interactions.
Deprecated: Linear Cohesion
Linear Cohesion V1 model has been marked as deprecated and will be removed in EDEM 2022. This has been replaced by Linear Cohesion V2, which was added to EDEM to account for size distribution of particles. Users will be able to analyze simulations previously run using Linear Cohesion but will be unable to resimulate these decks without upgrading to Linear Cohesion V2.

EDEM 2021.2 contains fixes for the following issues:
The Total Removed value in the Solve Report was incorrect when using the CUDA based solver.
The percentage of the mass used for the volume packing was based on number of particles rather than mass of particles.
Information about removed particles was stored in the EDEM data files when using the polyhedral solver.
The default values for CAD import could generate a poor mesh.
Contact information could be discarded incorrectly. The issue was most pronounced in simulations involving spheres with a large contact radius compared to the physical radius contacting complex geometries.
The Block factory could cause a crash on starting the simulation when run on the GPU engine if no particles were present in the block.
The filter function could allow geometries to be given the same name, leading to a crash.
Renaming a grid bin group could change its dimensions.
A crash could occur when a simulation with a factory attached to a geometry group was replaced.
A memory leak could occur when using certain Coupling Interface functions.
The Simulation would continue running where a body force model had returned and error (eFatalError).
The last timestep in the simulation was not saved correctly when the command line '-n' option was used with the OpenCL or CUDA solvers.
When geometry deformation was extreme particles could pass through the geometry.
The progress bar text when using dark theme was not visible.
The H5Recompress script could delete simulation files on Linux if run outside the EDEM application.
Stress queries from within the GUI would always report a zero value under certain conditions.
Changing the Contact Plasticity Ratio in the Edinburgh Elasto-Plastic Adhesion configuration panel could result in an incorrect recommended timestep unless the interface was closed and reopened.
Exporting data during simulation while using queries which contain selections should work as expected now.
Exported stress values could be incorrect when more than one type of particle was used.
Geometries from previously loaded simulations could be retaining in the model viewer when starting a new simulation or opening a deck containing no geometry elements.
An error could occur when saving a material block.
The Delaunay meshing could modify particle shape and should only be used in certain situations. Delaunay re-mesh now off by default.
An error was reported when using file compression on Linux.
Suffixes for wear constant and Vickers hardness were incorrect.
No prompt to save when switching between Creator and Simulator if pressure or filepath changed in the FlexTire interface.
A Field Data file (.efd) was being saved when it didn't have to be. This will now only be generated when required
Geometries were not updated in the Model Viewer, when the size and position of geometries changed and when using Modern Geometry Rendering.
Field Volume rendering order was incorrect, so would appear inside out and would not render when viewed from certain directions.
The Field Data plane position was not stored on close of EDEM and would reset when opening the simulation.
Polyhedral properties were not recalculated if the shape was modified.
Unsymmetrical forces from EEPA contact model were not stored.
A crash could occur when rewinding a simulation with a factory selected.
Kinematic vectors were not displayed when using Legacy Geometry rendering.
Geometries would appear clipped in the Creator and Simulator when clipping planes added in the Analyst.
Changes to polyhedral particle definition mid-simulation were not accepted by factories. New particles would be generated with the original shape.
A crash could occur during the compression of simulation files.
Running repeated simulations concurrently through the Coupling Interface could result in differences in results.
Simulation custom property changes were not added properly in some cases.
Caps on particle size for volume packing were not being applied when using a normal or lognormal distribution.
The last timestep in the simulation was not saved correctly when the command line '-n' option was used with the OpenCL or CUDA solvers.
Replaced geometry with auto-calculated center of masses was ignored by motions.
Multi-Sphere instanced rendering failed to show when using the Multiple display option in EDEM.
Simulation custom properties were not calculated correctly with Polyhedral particles with more than 64 faces.
Geometry would not import or open help when linux install path on had "altair" in the install path more than once.
The system would not respond to coupling client commands after a simulation run in batch mode with the wait flag enabled.
An error message would appear when using the Materials Database if a plugin file was referenced within any of the entries but not present in the current simulation.
Caps on particle size for volume packing were not applied when using a normal or lognormal distribution.
A crash could occur when adding Volume Packing to a geometry where geometries had been deleted.
A crash could occur when Coupling Interface client attempts to load or save a deck in batch mode.
A crash could occur when loading a deck, via the Coupling Interface, in batch mode