Altair Radioss 2020.1 Release Notes

New Features

Flexible body

Radioss Starter can directly import DMIG (KAAX and MAAX) data (.pch text file) to create the corresponding flexible body (/FXBODY).

Radioss Starter

New Starter option /CHECK/RFILE/OFF to quickly check the model with the Radioss Starter. The restart file will be not written. This option is also available as a Starter executable command line option -check.
New Starter executable command line option -outfile=[path] to write all files in a user-defined folder. The Starter writes the Starter output and Starter restart files in the defined output folder when -outfile option is used.

Radioss Engine

New Engine option to cancel the restart file creation even at the end of the computation with the keyword /RFILE/OFF in the Engine file. This option is also available as an Engine executable command line option -norst.
New Engine executable command line option -outfile=[path] to write all files in a user-defined folder. The Engine reads the created restart files in the defined output folder when -outfile option is used.

Materials and properties

New material /MAT/LAW108 (SPR_GEN) for spring elements with the same behavior as spring property /PROP/TYPE8 (SPR_GENE).
New material /MAT/LAW113 (SPR_BEAM) for spring element with the same behavior as spring property /PROP/TYPE13 (SPR_BEAM).
The new spring property /PROP/TYPE23 (SPR_MAT) which must be used with the new material laws /MAT/LAW108 (SPR_GEN) and /MAT/LAW113 (SPR_BEAM).
New parameters for the latent heat of martensite and Taylor-Quinney coefficient for element temperature computation due to the phase change in the material law /MAT/LAW63 (HANSEL).

Enhancements

Submodel (//SUBMODEL)

The failure model /FAIL/ORTHSTRAIN is now compatible with submodel.
Correction of Starter error when a /FRAME/NOD is defined inside a submodel.
Correction of Starter error when damping is defined in the crushable spring property /PROP/TYPE44 (SPR_CRUS).
Section force is now fully compatible with submodel.

Automatic Dynamic Relaxation (/ADYREL)

Improvement of the /ADYREL option for multi-run (Engine) simulations. The results may be different between a model computed with one run or several runs.

Unit system conversion

Thermal parameter for material (/HEAT/MAT) is now compatible with /UNIT system.
A /UNIT system can be added in the local coordinate system /SKEW/FIX and /FRAME/FIX.
Two new scale factors c₀ and P_b0 for the unit conversion of the concrete/soil material law /MAT/LAW81.
New reference stress value Tau for the Bergstrom-Boyce viscous model in the material law /MAT/LAW100 (MNF).
A new scale factor for the Arruda-Boyce function in the material laws /MAT/LAW92 and /MAT/LAW100 (MNF).

Contact interfaces

Contact thermal behavior can be activated in the contact interface /INTER/TYPE19 for the node to surface treatment.
Improvement of the initial penetration check with the contact interface /INTER/TYPE25 for specific models with shell thickness bigger than the mesh size. Unexpected forces were previously calculated.

Imposed conditions / loadcase

Several load blast cards /LOAD/PBLAST can be used in one model.

Materials

New parameters for concrete material law /MAT/LAW24 (CONC) with I_cap =2: Reference plastic strain for plastic hardening (Eps₀), Reduction factor for plastic hardening default (h_fac).
No more useless message “WARNING LOAD INCREMENT TOO BIG IN ELEMENT” in the concrete material /MAT/LAW24 (CONC). This removal reduces the size of the Engine output file and reduces computation time.
Improvement of the hourglass energy computation with foam material law /MAT/LAW70 (FOAM_TAB) for single precision to get similar results as the double precision.
New initial pressure FP₀ option in foam material law /MAT/LAW77 and F_cut default value is changed from 1E+30 to 1E+20.
New reference stress value Tau for the Bergstrom-Boyce viscous model /MAT/LAW95 (BERGSTROM_BOYCE). This option is necessary to used different unit systems.
New error message is printed when 2D solid element /TRIA is used with material law other than /MAT/LAW151 (MULTIFLUID).
New error message in case /EULER/MAT or /ALE/MAT is not defined on the material law /MAT/LAW151 (MULTIFLUID).

Monitored volumes

New option I_equi to take into account the volume change during the relaxation/loading phase defined by T_relax in the perfect gas monitored volume MONVOL/GAS.

General and Engine features

By default, the restart files are written every 1000000 cycles instead of 5000 cycles in the card RFILE/n. This modification improves the computation time by reducing the amount of I/O in the hard drive.
Improvement of the computation speed with the SPMD version for a large automotive crash model.
Improvement of the computation time with the time step option /DT1/BRICK/CST/1. This time step definition gives better solid model stability with poor mesh element quality.

Resolved Issues

Rayleigh Damping (/DAMP)

Starter correction issue when local coordinate system Skew_ID is defined in /DAMP card.
Correction of a parallel arithmetic issue (/PARITH/ON) for Rayleigh damping applied in a local coordinate system.

Animation output (H3D and A files)

Improvement of the internal energy output /ANIM/ELEM/EINT and /H3D/ELEM/EINT for shell elements.
Correction of the degenerated brick elements display when using the native /H3D output.
Several entities were not output in the .h3d file when it is requested by sensor (/H3D/LSENSOR) and when the card /H3D/DT is not set in the Engine file.
Color function (/H3D/*/COLOR) is correctly output when more than 10 sub-materials was defined in the material law /MAT/LAW151 (MULTIFLUID).
Correction of numerical issues with Eulerian grids when using /EULER instead of /ALE in the material card. The Mach value was not correctly computed (/H3D/ELEM/MACH, /ANIM/ELEM/MACH).
The external force output in the native H3D (/H3D/NODA/FEXT) was not correctly assembled at the boundary of the SPMD domains.
Display issue correction for the grid point tensors (/H3D/NODA/GPS) for models with several parts and different solid element types in SPMD/HMPP simulations. The value was wrong at the domain decomposition boundary with single precision version only.
Display issue correction for the contact pressure (/H3D/NODA/PCONT) for a model with several parts and different solid element types for SPMD/HMPP simulation.
The equivalent stress value (/H3D/SHELL/SIGEQ) was missing.

Unit conversion correction

Starter output file correction after unit conversion of the detonation plan /DFS/DETPLAN/NODE. The coordinate was not updated.
Improvement of the simple fluid pressure loading (/LOAD/PFLUID) when defined multiple times in the model using different unit systems.
Unit conversion correction for the parameter a of the material law /MAT/LAW32 (HILL).
Unit conversion correction for the parameter E_inf in the material law /MAT/LAW43 (HILL_TAB).
Several corrections for the unit conversion for the material law /MAT/LAW68 (COSSER).
Correction for the functions scale factor unit in /MAT/LAW77.
Dimension was missing for minimum time step DT_min in the thick-shell property /PROP/TYPE20.
Starter behavior improvement with the parameter delta_t in section force (/SECT) when different unit systems are used.

Imposed conditions / loadcase

Correction of a memory issue when the model has a lot of functions (> 500000) and imposed motion (velocity or displacement).
Starter was failing on a specific model with the imposed flux option (/IMPFLUX).
Improvement of /LOAD/PBLAST when used with /PARITH/ON. The results were not correct in case of multiple loads with different surfaces.
Improvement of the SPMD decomposition when multiple surfaces are defined in pressure loads /LOAD/PFLUID and /LOAD/PBLAST.

Initial condition

Correction of the I_solid flag in the initial state for brick elements (/INIBRI/*) when both I_solid=17 and I_solid=18 are defined in the same model.
Improvement of the initialization (force, deformation) of the spring element /PROP/TYPE23 (SPR_MAT) and /PROP/TYP25 (SPR_AXI) with the option /INISPRI. The initialization was done correctly but the value was released after the 1st cycle.
Correction of wrong initialization of the volume fraction (/INIVOL) with a surface tangent to boundary faces.

Contact interfaces

Correction of Starter memory allocation for /INTER/TYPE19 + /INTER/SUB on specific model. The Starter was failing.
Improvement of the forming contact interface /INTER/TYPE21 for some specific model. Some nodes remained stuck on the master surface.
Improvement of the contact energy output for the contact interface /INTER/TYP24. Some elastic contact energy was missing (output issue only).
Correction of a numerical issue when sub interface (/INTER/SUB) is linked to the interface /INTER/TYPE24 with edge to edge treatment (I_edge=1). The Starter was failing.
Correction of the I_gap value in the Starter output file for /INTER/TYPE25. It was always output as 1.0.
Improvement of the contact interface energy output for the contact interface /INTER/TYPE24 and /INTER/TYPE25. The contact energy was too high.

Materials

Improvement of the contour output for the unavailable phase for material defined in multi-material law /MAT/LAW51 (MULTIMAT) with I_form=12. For example, the vfrac(4) was not correctly output for a material with only 3 phases. The contour value is now zero as expected.
Correction of volumetric fraction initialization in case explosive sub-material ID is not equal to 4 for multi-material /MAT/LAW51 (MULTIMAT) with I_form=12.
Correction of an initialization issue when the non-reflecting frontier /MAT/LAW51 (MULTIMAT) with I_form=6 is defined before the multi-material /MAT/LAW51 (MULTIMAT) with I_form=12.
Improvement of the output (energy, pressure) for a specific model (air tunnel) for the multi-material /MAT/LAW51 (MULTIMAT). The results were different with fluid material /MAT/LAW6 (HYDRO) and boundary material /MAT/LAW11 (BOUND).
The parameter P_sh is now correctly taken into account and allowed to work in relative pressure. This correction is done for the equation of state of /MAT/LAW6, /EOS/MURNAGHAN, /EOS/NOBLE-ABEL, /EOS/STIFF-GAS, /EOS/IDEAL-GAS, /EOS/COMPACTION, and /EOS/LSZK.
Material /MAT/LAW60 (PLAS_T3) is no longer failing when fct_ID_p is defined.
Stress computation improvement which reduces oscillations when strain rates are used in connection material law /MAT/LAW83.
Improvement of the unloading behavior for the foam material laws /MAT/LAW88 and /MAT/LAW90 defined with strain rate dependency.
Improvement of the HEPH solid element (I_solid=24) behavior for foam material law /MAT/LAW90.

Monitored volumes

Solution improvement when a surface is defined with 3-node and 4-node shell elements. Specific models were diverging.

Element properties

Correction of a numerical issue when a rigid body (/RBODY) is defined with a sensor and contains quadratic tetrahedron element and the option I_tetra10=2 in the solid property /PROP/TYPE14 (SOLID).
Improvement of the quadratic tetrahedron element /TETRA10 with I_tetra10=2 in the solid property /PROP/TYPE14 to reduce the difference between double and single precision, /PARITH/ON and /PARITH/OFF.
Improvement of the model stability with tied contact /INTER/TYPE2 and quadratic tetrahedron element /TETRA10 with I_tetra10=2 in the solid property /PROP/TYPE14. The model was failing during the second restart file or with check point restart (/CHKPT).
Improvement in the Starter of the time step estimation in the Starter for quadratic tetrahedron element /TETRA10 with the flag I_tetra10=2 in the solid property /PROP/TYPE14. The estimated nodal time step was around 10% too high.
Correction of memory allocation issue for a model when linear tetrahedron element TETRA4 and hexahedron element /BRICK share the same solid property /PROP/TYPE14 with the option I_tetra4=1.
The linear tetrahedron (/TETRA4) nodal stiffness was canceled when the flag I_solid=14 was used in the solid property /PROP/TYPE14.

General

Starter correction for a model with Madymo coupling that caused the computation to fail.