Altair Radioss 2021.2 Release Notes


  • Improvement of the capability and performance of the Radioss reader for LS-DYNA format models. A new connection material has been created to enhance LS-DYNA format model reading.
  • Several material laws are added to model corrugated paperboard and paper material, rubber with tabulated input or aluminum/metallic foam.
  • New options for FSI application have been developed to map current state from a first analysis (for example, detailed 2D analysis of blast) to initial state of a second model (local 3D fluid and structure analysis when the shock wave is close to the target).
  • Some corrections for an improved, faster and more robust solution.

New Features

LS-DYNA Reader
The following cards can be read in this version. The details of the supported parameters are described in the Reference Guide.
Material and failure models
  • /FAIL/ALTER: Improvements and new options in the failure model for better failure for pedestrian impact
  • /MAT/LAW111 (MARLOW): New tabulated hyper-elastic material law with Marlow formulation
  • /MAT/LAW112 (PAPER, XIA): New material law based on Xia formulation to model corrugated paperboard and paper
  • /MAT/LAW115: New material law to model aluminum foam based on the Deshpande and Fleck formulation. There is also a new option /PERTURB/PART/SOLID to model density random distribution and perturbation
  • /MAT/LAW116: New cohesive material with elasto-plastic behavior, rate dependent and energy or elongation failure model
Element and properties
  • New flag Itetra10=3 in solid properties (/PROP/TYPE14, /PROP/TYPE6) and in default card (/DEF_SOLID) with the same formulation as Itetra10=2 and time step of linear tetrahedron element /TETRA4. This formulation can be unstable with bad shaped tetrahedron elements.
  • /SENSOR/DIST_SURF: New sensor based on distance between a node and a plane defined by 3 nodes
  • /SENSOR/HIC: New sensor based on Head Injury Criteria (HIC) computed from a given accelerometer


Model Files Removed from Installation Package
To reduce the footprint size, the following tutorial model and demo model files are no longer included in the local installation. You can now find zipped tutorial model files and demo model files on Altair One via the Altair Community, Altair Marketplace, and Altair Connect sites. Altair recommends that you create an Altair One account and use it as your primary portal to access product documentation, a Knowledge Base, and customer support.
Tutorial Model Files
LS-DYNA Reader
  • Several control cards, database cards and hourglass are skipped during model reading
  • *MAT_COHESIVE_MIXED_MODE_ELASTOPLASTIC_RATE is now mapped to connection material /MAT/LAW116
  • *MAT_NULL is kept for the beam and truss elements
  • Improvement of beam reading for *SECTION_BEAM with ELFORM=2
  • The option ADD is now supported for the card *SET_SEGMENT_ADD
  • Elform=-1 in *SECTION_SOLID is now read as HEPH solid element
Submodel (//SUBMODEL)
  • Improvement of the error message in case the input format set in the header card does not exist
  • Options now compatible with submodels:
    • /EULER/MAT
    • /ALE/MAT
    • /INTER/TYPE18
  • Improvement of submodel translation and rotation using the /TRANSFORM card
General set (/SET)
  • New keys for sets:
    • RBODY to add, remove rigid bodies
    • SUBM to add, remove submodels
    • SET to add or remove sets
  • Only external facets of solid blocks are selected with the key ALL.
  • New type of set /SET/COLLECT and Key =SETCOL. All sets with type COLLECT and the same ID are assembled in the Starter and are not renumbered if defined in a submodel
  • The option intersection (I) is extended to most of the keys
Animation files (/ANIM or /H3D)
  • H3D results are written at the end of the run in the .h3d file
  • Radioss version is printed in the .h3d general information
  • New output to display the maximum force seen over the time on the nodes in contact (from main or secondary side) with the keyword /H3D/NODA/CONT/MAX or /ANIM/VECT/CONT/MAX
  • /H3D/NODA/SKID_LINE: The skid lines from interface TYPE21 are now also displayed on the tool side. This output will help estimate tool wearing.
  • "Corner data" can be requested for stress and strain tensors with the keyword /H3D/SOLID/TENS/STRESS/CORNER_DATA and /H3D/SOLID/TENS/STRAIN/CORNER_DATA. The stress and strain tensors are output for each node of each solid element.
Contact interference
  • Engine option /DEL/INTER is now compatible with /INTER/TYPE25
  • Improvement of the computation time of the contact /INTER/TYPE25 (mainly with edge-to-edge treatment)
  • Improvement of the contact stiffness value for /INTER/TYPE7 with integrated beam elements (/PROP/TYPE18)
FSI, ALE and Eulerian features
  • New option to easily initialize fluid domain from previous run. Pressure, velocity, density end energy can be stored in binary file
  • The created data can be mapped on the new model (2D or 3D) with different geometry to recover the previous state
  • Fluid / Structure contact interface (/INTER/TYPE18)
    • New option to automatically remove nodes with Lagrangian formulation from the ALE set of the contact interface
    • Automatic gap and stiffness computation for better contact behavior with less leakage and improved reaction force computation
  • /LOAD/PBLAST detonation position can now be selected with a node ID, instead of coordinates
Input and output state files
    • New initial state file output with LS-DYNA format for shell elements (node, shell connectivity, thickness, stress and strain tensors).
  • New option for the strain tensors in the global coordinate system for shell elements
Material and failure models
  • Improvements and new option in the glass failure model (/FAIL/ALTER) for better failure modeling for pedestrian impact.
  • Better compatibility of /FAIL/GURSON with /DT/NODA.
  • New warning message in the Starter output file in case Batoz shell element (Ishell=12) is used with XFEM failure model (not compatible). The XFEM flag is automatically switched off for the failure model.
  • The mesh size dependency in tabulated failure model (/FAIL/TAB1) can be applied only for a defined range of triaxiality.
  • It is possible to input failure value in engineering strain or total strain in the failure cards /FAIL/TENSSTRAIN, /FAIL/VISUAL and /FAIL/ORTHSTRAIN.
  • Output improvement of the failure information for composite material /MAT/LAW25 for each Gauss integration point in each layer in the Engine output file (_0001.out)
  • Dependency of Young’s modulus on martensite phase fraction of shape memory alloy material (/MAT/LAW71) is now available for shells
  • Improvement of the plastic strain increment computation for solid and shell elements of Hill MMC material (/MAT/LAW72) for better and more accurate results
  • Phase transformation is now available during heating process for the ultra-high strength steel material (/MAT/LAW80)
  • New error message is now printed when an input curve does not have the point (0,0) which is mandatory in tabulated hyper-elastic material (/MAT/LAW88)
  • The equivalent strain rate is now output in the animation files (/ANIM/BRICK/EPSD) and H3D file (/H3D/SOLID/EPSD) for the visco-elastic foam tabulated material (/MAT/LAW90)
  • New input check and improvement of the CONVERSE material (/MAT/LAW93) behavior for specific case
  • Improvement of the viscosity behavior for Bergstrom-Boyce material model (/MAT/LAW95)
  • The option /PERTURB/FAIL/BIQUAD can be used for components with solid elements and SPH
Element and properties
  • Thermal conduction and thermal expansion is now available for beam elements (/PROP/TYPE3, /PROP/TYPE18) with the keywords /HEAT/MAT and /THERM_STRESS/MAT.
  • Improvement for the handling of the universal /PROP/KJOINT2 when the 2 axis are not exactly orthogonal.
  • With Ithick=-1 (recommended value) in /PROP/SHELL, the thickness of the shell element remains constant for elastic material (/MAT/LAW1). This setting ensures improved element stability in case of large deformation (which is not expected for material LAW1).
  • Global integration (N=0) is removed for material LAW2, LAW22, LAW36, LAW43, and LAW60, and automatically set to N=3 in the shell properties (/PROP/SHELL). Small result differences are expected from previous versions.
  • An error is added in the Starter when material defined on the SPH component is not compatible with SPH formulation (/PROP/SPH).
Other enhancements
  • Improvement of the warning message #194 for the different groups of property and material to clarify understanding
  • New user routine for check-out and check-in of licenses (UA, APA) for the user material laws
  • User Sensors (/SENSOR/USERi) related to nodes can now be used with SPMD/HMPP version
  • New error message appears if the part list ID is empty in the /STATE/DT card
  • Tables (/TABLE) with different initial and final abscissas no longer returns an error message
  • The total mass and added mass are printed in the Engine output file each time a cycle is printed
  • Improvement of the error message when an input card does not correspond to the input version defined in the /BEGIN card

Resolved Issues

LS-DYNA Reader
  • Default value for CN in the card *AIRBAG_SIMPLE_PRESSURE_VOLUME is now set to 1
  • Set of nodes in the card *BOUNDARY_SPC_SET is used, in cases where both have the same ID
  • Reading improvement when a boundary condition is applied on the secondary node of the rigid body built from node set (*CONSTRAINED_NODAL_RIGID_BODY)
  • Transformation (*DEFINE_TRANSFORMATION) is now applied on the correct set of nodes
  • Reading improvement for element mass (*ELEMENT_MASS_PART_SET) when FINMASS is defined
  • Improvement of the rigid body reading defined in includes (*INCLUDE). The node created for the main node of the rigid bodies could have the same ID for some specific cases.
  • Sets (*SET):
    • Reading improvement in case 2 SETs with different types have the same ID. Error message is printed when *SET (same type) is duplicated.
    • Several other reading issues are fixed
Animation files (/ANIM or /H3D)
  • Correction of the animation file for the beam and truss elements with void material law (/MAT/LAW0). Beam and truss elements were not displayed correctly.
  • Memory issue for stress and strain output in the animation file with SPH elements
  • Improvement of the stress output (MEMB, BEND, UPPER, LOWER) for shell elements in order to be more consistent across different material laws.
  • /H3D: Correction of the position update display for the moving cylindrical rigid wall. The display of some facets was not correct.
  • Radioss Engine was failing when /PROP/TYPE3 was defined in the model and beam stress/strain tensors (/H3D/BEAM/TENS/*/NPT=i,ALL) was requested.
  • Improvement of the output for curvature of shell element (/H3D/SHELL/TENS/STRAIN/BEND) with integration points through the thickness
Material and failure models
  • Correction of memory allocation in Radioss Starter with /FAIL/GURSON. The computation was failing for models with this failure card.
  • The values Y0 and Yc of failure model /FAIL/LAD_DAMA print as the values themselves in the Starter output file, instead of as the square root of the value.
  • Improvement of the computation time for solid elements with Ismstr=10 and elastic material (/MAT/LAW1)
  • Correction of numerical instability for specific hot forming application with material /MAT/LAW80. The element was diverging.
  • Correction of memory initialization issue with material /MAT/LAW88. Engine may fail with segmentation fault.
  • Correction of the plasticity algorithm in CONVERSE material law (/MAT/LAW93) for more accurate results. The stress was not accurate in case of large plastic strain value.
  • Improvement of the behavior of the viscosity model for better stability and accuracy in the multi network framework material law /MAT/LAW100
  • The backstress computation is correct in /MAT/LAW78 when work hardening stagnation parameter (h) is greater than 0 for shell elements.
Input and output state date and files
  • Correction of the initial pressure computation of /INIBRI/STRS_FGLO for single precision version.
  • For ply-based composite components, only the first integration point through the thickness was written in the state file (.sta)
  • The initial fraction volume card (/INIVOL) can now be used in the multi-domain computation (/SUBDOMAIN)
Element and properties
  • Correction of numerical issue between fabric material, triangle elements (/SH3N) and total small strain formulation (Ismstr=11)
  • Correction of unit conversion issue for the injected mass in the injector property (/PROP/INJECT1)
  • Option Ishell in shell property (/PROP/SHELL) no longer is reported in the part review section of the Starter output file (0000.out), if property is referenced on multiple /PART (/SHELL and /SH3N)
  • Solid property (/PROP/SOLID):
    • Numerical issue correction for solid parts using “solid to SPH” option and SPMD version
    • Correction of Starter check issue for model with quadratic tetrahedron elements (/TETRA10) with Itetra10=2 and several kinematic conditions on the middle node
    • Element behavior improvement with Isolid=18 and elastic material /MAT/LAW1. Model was diverging for some specific models.
  • Correction of strain rate calculation for the integrated beam element (/PROP/TYPE18)
  • Correction of the spring behavior for the function fct_ID4 for the spring element /PROP/TYPE4 and /PROP/TYPE12. Time step is also improved.
  • Radioss Starter no longer fails when the /INIBRI card is defined inside a submodel for specific models
  • The variable Ptlim is read correctly for contact interface /INTER/TYPE5 when defined inside a submodel
  • Correction of unit reading in the include files defined in the submodel. Radioss Starter no longer shows an error when units system are defined with letters and numbers
Other corrections
  • /ADYREL: Improvement of the automatic damping parameter when initial stress is set in the solid element (/INIBRI). The damping was not big enough.
  • The header for MAAX is no longer interpreted when read in the flexible body (/FXBODY).
  • Correction for the new reader with old Radioss format for the edge to edge contact (/INTER/TYPE11) and when cards are missing.
  • Correction of memory allocation issue in Starter for FSI contact interface (/INTER/TYPE18) defined with a group of bricks.
  • Correction of airbag meshing using HyperMesh mesher (Kmesh=14) in the FVM airbag (/MONVOL/FVMBAG1, /MONVOL/FVMBAG2) .
  • Correction of input issue with parameters (/PARAMETER) used with sign "-" in the initial velocity card (/INIVEL/AXIS)
  • Correction for one temporary file behavior in the subdomain modeling (/RAD2RAD/ON). The file was not correctly closed, and its size could be very large on the win64 platform with specific models.
  • Correction of the wrong behavior when local coordinates are used in the /RBE2
  • The sensor /SENSOR/OR now de-activates when both linked sensors are de-activated.
  • Computation correction with SPMD version when all nodes of the SPH inlet (/SPH/INOUT) are defined in the same RBODY.
  • Surfaces are correctly removed in the card /SURF/DSURF.
  • Correction of the position defined on set of nodes in the option /TRANSFORM/POSITION. The transformation was done in the opposite direction.
  • The 2D 3 noded solid element (/TRIA) number is now correctly reported.
  • Improvement of the Starter computation time for specific models with a lot of time history output (/TH).
  • Correction in the contact interface /INTER/TYPE10 of secondary node sorting issue when tied condition is released.
  • Correction of the jetting node reading in /MONVOL/COMMU1. The first node was not correctly read since version 2021.1.