Altair Radioss 2024.1 Release Notes

Highlights

  • Continuous development for the LS-DYNA format reader.
  • Improvement for the shell composite to better take into account the shell offset in the element and also in the contact interface.
  • Many other enhancements in the crash and ALE/FSI analysis features, including material & failure, contacts, SPH and output.
  • Several verification problems have been added to the documentation.

New Features

LS-DYNA Format Reader
New LS-DYNA format reading capability
  • *CONTACT_AIRBAG_SINGLE_SURFACE
  • *DAMPING_RELATIVE
  • *DATABASE_HISTORY_SPH
  • *DEFINE_ELEMENT_DEATH
  • *ELEMENT_SEATBELT_SLIPRING
  • *ELEMENT_SPH
  • *EOS_001 (LINEAR_POLYNOMIAL)
  • *INITIAL_AXIAL_FORCE_BEAM
  • *MAT_001_FLUID (ELASTIC_FLUID)
  • *MAT_138 (COHESIVE_MIXED_MODE)
  • *SECTION_SPH
ALE and FSI options
  • New ALE grid control /ALE/GRID/FLOW-TRACKING which is computed according to the center of mass motion of the ALE domain. This option can be used for bird strike with a bird and the surrounding air modeled in ALE domain.
  • Sliding Wall boundary condition (/BCS/WALL) can block or allow flow normal to a given face for collocated scheme (multi-fluid material, /MAT/LAW151).
  • New simple equation of state function /EOS/EXPONENTIAL to model pressure and time and independent from density and energy.
Elements and Properties
  • More predefined sections have been added in the integrated beam property /PROP/TYPE18.
  • New flag Ioffset in /DEF_SHELL to take into account the shell offset in the contact interfaces (/INTER/TYPE7, 11, 18, 19, 21, 24 and 25) for composite shell elements. New output /H3D/NODA/SHELL_OFFSET to have a better comprehension of contact behaviors when Ioffset=1 is used.
Materials and Failure Models
  • New material law /MAT/LAW126 to describe brittle materials, such as ceramics and glass based on the first Johnson-Holmquist model: JHC
  • New damage output for composite failure modes per material and damage mode.
    • /H3D/ELEM/DAMG/ID=<mat_ID>/MODE=<mode ID>
    • /H3D/ELEM/DAMG/ID=<mat_ID>
    • /H3D/ELEM/DAMG
  • New model /FAIL/FRACTAL_DAMAGE for random walk damage initialization in Starter.
  • New output /H3D/ELEM/FAILURE for the reserve factor and failure index for each listed failure model.
Loadcase, Constraints and Contact Interfaces
  • New option /PRELOAD/AXIAL to set preload axial force for spring beam and truss elements.
Engine file options
  • New option /ADYREL/1 to apply automatic dynamic relaxation on a set of nodes.

Enhancements

LS-DYNA Format Reader
  • New flags SOFT=-7 (node to surface), -11 (edge to edge) or -19 (surface to surface with edge treatment) in *CONTACT_AUTOMATIC_GENERAL to get contact with nonlinear stiffness.
  • New flag SOFT=-7 in *CONTACT_ERODING_SINGLE_SURFACE to use contact interface with nonlinear stiffness.
  • Initial and maximum time step from LCTM in *CONTROL_TIMESTEP is used for the time step (using /DTIX).
  • Keyword *DATABASE_HISTORY_{OPTION}_SET is now read for all input types.
  • Reading improvement for the lower plastic strain value EFMIN in *MAT_015.
  • Reading improvement in case H > 0 but unloading curve LCU is not specified for *MAT_121.
  • The element formulation ELFORM=3 from *SECTION_SOLID is now interpreted as fully integrated solid element (Isolid=18).
ALE and FSI options
  • New error message in case of several /ALE/GRID definitions. Only one grid control is used.
  • The default grid control formulation is changed from /ALE/GRID/DONEA to /ALE/GRID/DISP to get better stability. Small differences in the results are expected from the previous results for models where grid control formulation is not explicitly defined.
  • Nodal speed of sound can now be output for the ALE/EULER components with the keyword /H3D/NODA/SSP.
  • The default value for minimum pressure (Pmin) in /LOAD/PBLAST changes from 1E-20 to 0.0 and lower bound for decay parameter, b of the modified Friedlander model (Imodel=2) is set to 0.0.
Elements and Properties
  • Improvement of the local coordinate definition for the single precision version for beam elements (/BEAM).
  • The distance Z0 is now defined as the position from the meshed surface to the bottom of the stack in shell composite properties /PROP/TYPE17, /PROP/TYPE51, /STACK. This change is done to be consistent with other solvers.
  • Improved SPH numerical accuracy by improving option order=1 and making it compatible with SPMD.
  • Non-local approach /NONLOCAL/MAT is now compatible with degenerated under-integrated bricks (thick shells and solid).
  • Flag IP=26 is added to /PROP/TYPE9, /PROP/TYPE10, /PROP/TYPE11 and /PROP/TYPE16.
Materials and Failure Models
  • New parameter in /FAIL/JOHNSON to define the lower bound strain value for the failure criteria.
  • The function/table FCT_SR can be defined with natural log input for strain rate dependency in failure model /FAIL/TAB2.
  • New input curve for temperature effect applied on the damage table in failure model /FAIL/TAB2. It is used only if temperature effect is not defined in the table (dimension < 3).
  • Materials /MAT/LAW44 and /MAT/LAW109 can be used with Equation of State (/EOS) for solid elements.
  • Computation scalability is no longer dependent on the function size for materials /MAT/LAW50, /MAT/LAW76 and /MAT/LAW90.
  • Improvement for the strain rate input and output in material /MAT/LAW83. The strain rate filtering is activated by default (Fcut = 10000Hz) for the total strain rate filtering (Israte=0).
  • The initial elastic modulus E0 is now updated according to the maximum initial tangent of the input curves in /MAT/LAW90. The maximum elastic modulus is now the minimum value of the maximum curve tangent and 100 times initial elastic modulus E0.
  • New option Tflag curves in /MAT/LAW90 to have linear elastic behavior in tensile using E0.
Loadcase, Constraints and Contact Interfaces
  • The option /TABLE is now compatible with encryption.
  • New gap scale factor Edge_scale_gap to scale gap_min for the edge to edge contact in contact interface /INTER/TYPE19.
  • The option to define contact gap "thick" is now available for spring, beam and truss elements and can be used for contact interface /INTER/TYPE7, /INTER/TYPE11, /INTER/TYPE19, /INTER/TYPE24 and /INTER/TYPE25.
  • New Key=ELLIPS (hyper ellipsoid surface), Key=NODENS (unsortable node set) and Key=PLANE (plane surface) in the general set /SET/GENERAL.
  • Reference metric (/XREF, /EREF) is now compatible with fully-integrated solid elements Isolid=18
Animation and Time History Output
  • New output variable VX, VY and VZ for /TH/PART and /TH/SUBS
Engine file options
  • /INTER: New error message in case Tstart ≥ Tstop.
  • Improvement of the solid element stability (/DT1/BRICK) with specific models with only few elements.
Other features
  • The command line argument -mds_libpath [PATH] is replaced by -mdsdir [PATH].

Resolved Issues

LS-DYNA Format Reader
  • *CONTACT: correction of the mapping for the parameters SST and MST (optional contact thickness).
  • *DATABASE_CROSS_SECTION_PLANE: reading correction of the finite plane size.
  • *DEFINE_TABLE_2D: scale factor SFA was not considered for some specific cases.
  • *MAT_124 (PLASTICITY_COMPRESSION_TENSION): reading improvement in case FAIL=0. The default value was not correctly read.
  • *MAT_224 (TABULATED_JOHNSON_COOK): improvement of the material reading for the failure behavior.
  • *SECTION_BEAM: improvement of the cable section (ELFORM=6) parameter reading in case of material different from *MAT_146.
  • *PART_COMPOSITE: correction of reading error for specific models. Ply ID could be identical to an already existing property ID.
Elements and Properties
  • /DRAPE: correction of memory allocation issue for specific models.
  • /PLY, /PROP/TYPE19: correction of memory allocation issue with specific composite models.
  • /PLY, /PROP/TYPE19: correction of ply information in Starter output file (_0000.out).
  • /PROP/TYPE11: correction of the failure behavior in case of shell offset (Ipos=1) and material law /MAT/LAW25 (Iform=1).
  • /PROP/TYPE13, /MAT/LAW113: correction of the multi-directional failure criterion computation.
  • /RETRACTOR/SPRING: correction of memory allocation issue for SPMD/HMPP version.
  • /SLIPRING: correction of the slipring check in case it is linked to a rigid body which is merged
Materials and Failure Models
  • /EOS: improvement of the sound speed calculation for materials /MAT/LAW44 and /MAT/LAW109.
  • /FAIL/ALTER: default value of Exp_n was not correctly defined to 16.0 as it is documented.
  • /FAIL/ALTER: correction of memory allocation for model with only 3 nodes shell element (/SH3N).
  • /MAT/LAW151: correction for unexpected detonation with specific model.
  • /MAT/LAW51: correction of momentum issue when the option /ALE/SUPG/OFF is used.
  • /MAT/LAW58: correction of animation outputs USR4, USR5.
  • /MAT/LAW87: improvement of the material parameter fitting with tabulated input (Iform=0) and specific models.
  • /MAT/SPR_SEATBELT, /MAT/SH_SEATBELT: correction of the seatbelt check in case an unused material is defined in the model.
Loadcase, Constraints and Contact Interfaces
  • /FUNCT, /TABLE: correction of singularity in logarithmic interpolation routine.
  • /GRNOD/BOX: correction of /BOX/CYLIN reading.
  • /IMPFLUX, /CONVEC: memory allocation correction.
  • /INISH3/STRA_F/GLOB: reading correction for shell elements with global integration (with /MAT/LAW1).
  • /INTER/TYPE2: correction of memory allocation issue with specific models with Spotflag=25 and Spotflag=28.
  • /INTER/TYPE25: correction of warning message when both surfaces are identical.
  • /INTER/TYPE7, /INTER/TYPE19: correction of the flag Irem_gap=2 behavior.
  • /INTER/TYPE7, /INTER/24, /INTER/TYPE25: correction of stiffness computation for Istf > 1 with SPH elements.
Animation and Time History Output
  • /ANIM/ELEM/VFRAC: correction of memory allocation issue for specific models.
  • /H3D/NODA/DMASS, /ANIM/NODA/DMAS: correction of numerical issue for models with tied interface (/INTER/TYPE2) with Spotflag=28.
  • /H3D/NODA/GPS, /H3D/NODA/GPSTRAIN: correction of the output value.
  • /H3D/NODA/PCONT2/TMAX: correction of memory allocation issue. Engine may fail before writing the first animation with specific models.
  • /H3D/SHELL/TENS/STRESS: correction of H3D writing issue for specific models.
Engine file options
  • /IMPL/MUMPS/OUTCORE: option was not printed in the documentation.
  • /STOP/LSENSOR: The stop time was affected by the value defined in /PRINT.
  • /TFILE: Specific model was failing in SPMD in case or force output in different time history files (/ATH, /BTH, etc).