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  • 971 Release 3.2 is Now Available

    Here are the release notes.
    Features and enhancements included in 971 R3.2 that were not available
    in 971 R3.1 include the following:

    New Material Models:
    *MAT_255 ()

    Enhanced Material Models:
    support of user defined failure for:
    - *MAT_123 (VP=1)
    - *MAT_103
    - *MAT_024 (VP=1)
    *MAT_191 now supports end release for beams
    *MAT_187 updates
    *MAT_126 add corotational local coord. system for formulation-1
    Add V option for aopt=3,4
    - *MAT_026
    - *MAT_126
    *MAT_036 added a cap to out-of-plane shear stress, when M is integer
    *MAT_172 added hourglass properties for shells
    *MAT_236 addes interior strain point calculation
    *MAT_ADD_THERMAL_EXPANSION now supports *LOAD_THERMAL_VARIABLE_SHELL
    *MAT_SEATBELT added error termination if the maximum slope in the
    loading curve exceeds that of the unloading curve.
    Added warning if modulus in a load curve table exceeds Young’s
    modulus for several material models.
    Print Warning if prca and prcb are blank in
    - *MAT_002
    - *MAT_022
    - *MAT_054
    - *MAT_055
    Added warning message or error termination if
    user inputs improper stress-strain curve for fitting for:
    - *MAT_027
    - *MAT_077
    - *MAT_177
    - *MAT_178
    Added the negative NUMINT option to material 123
    Added viscoplastic strain rate to:
    - *MAT_024 (VP=1)
    - *MAT_123 (VP=1)
    - *MAT_224 (VP=1)

    Implicit:
    Added synchronization of implicit time step after an adaptive
    remeshing.
    Added arclength method node control in MPP

    Boundary Conditions:
    Added implicit treatment of boundary prescribed orientation.

    Airbag:
    *AIRBAG_PARTICLE
    added flag on AIRBAG_HYBRID_CHEMKIN to turn on/off digitized load
    curves

    Output:
    messag:

    - Add list of untied nodes to MESSAG file for automatic tiebreak
    contact option
    d3plot
    - enable particle database in d3plot
    intforc
    - add MPP support for recent IOOPT option for intfor file.
    - Added IOOPT=3 for *DATABASE_BINARY_INTFOR

    Contact:
    Update for new weld option (Honda)
    Add a new feature to *TERMINATION_CONTACT allow the job to terminate when
    the maximum contact force is reached.
    Add guided cable contact to MPP
    Add flag to turn on shell element offsets in contact.

    General:
    Added optional thickness scaling for *INCLUDE_STAMPED_PART
    Added damage type DG_TYP=4 to DEFINE_CONNECTION_PROPERTIES
    Added MPP support for IFLAG=1 in CONSTRAINED_EXTRA_NODES
    Added new keyword *COMMENT
    Added “date” option for *VENDOR keyword added to R3
    Added a new command line option: ncheck=n
    where n is the of number of times to check the existence of input file.
    Support for constrained_extra_nodes option in selective mass scaling scheme
    Add warning about not supporting prescribed motion during modal
    superposition.
    Added user-specified spin speed for PRESCRIBED_ORIENTATION_VECTOR
    _____________________________________________________________________________
    The remainder of this file describes (sometimes quite cryptically) many other
    enhancements, additions, and bug fixes made since the release of
    LS-DYNA version 971 R3.1. These items are listed chronologically
    with the most recent items listed first.
    _____________________________________________________________________________


    improvements to global search for 2d_thermal contact

    several minor bug fixes in sensors

    Fix for *CONTACT_AUTOMATIC_…_TIEBREAK with OPTION=3 fixed in SMP – MPP was ok

    Fix restart bug related to SPH and full deck restart.

    Fix for rigid to deformable switching involving solid type 4
    tetrahedron.

    Fixed again two surface force transducers when used with segment based contact.

    Fix for MPP handling of tied thickness when specified on the contact card.

    Fix for MPP “groupable” override flag in pfile, for tied interfaces

    Correct Implicit handling of tied nodes with failure constraints.

    Fix for MPP output of peak pressures in intfor file: last state had
    all 0 for these.

    enabling r-adaptive load_thermal by initizlizing temperature after rezoning

    Fixed MPP brick weld initialization so that it will not hang.

    Fixed bug in ansys outout.

    Fixed bug for *AIRBAG_WANG_NEFSKE/HYBRID: Negative parameter A23
    with Part-ID > 9999999 was not working in single precision.

    Fix. Parameters from ELEMENT_BEAM_SECTION were not
    transformed and stored correctly. Manual has to be updated, too.

    Fixed possible division by zero in material 120.

    A bug fix in springback compensations

    Fix vc problem in automatic contact.

    fix for rigid body coordinates for implicit to explicit switch

    Fix: update orientation option for SMOOTH forming
    contact (MPP only)

    Fix for *DEFINE_CURVE_FUNCTION option RCF (now RCFORC)

    Fix for interior contact option 2

    Fix for *PARAMETER. Allowed a -minus sign before any parameter definition.
    For example, -&VAR1.

    Fix *sensor_define_node when n2>0

    Fix for frictional energy calculation for auto tiebreak
    contact

    Fix 2 minor include transform bugs

    Fix for case including both shell and 3D EFG.

    Fix for coordinate ID’s related to orthotropic materials to transformm
    to internal IDs in the keyword reader. This fix is to ensure that the
    dyna.str file works as intended.

    Fixes related to triangular shell element coordinate system to account
    for invariant numbering.

    Fix for material 57 to correct the calculation of internal energy
    density which was inaccurate for the large time step sizes of the
    implicit solver.

    Fix for INCLUDE_TRANSFORM related to material 181.

    Fixed potential 2 surface force transducer memory errors when used with
    segment based contact.

    Fix for rotations in MPP output of drdisp.sif file

    Fix format to tell users to check D3HSP for printed curve IDs. The
    curves may be internally generated in the keyword reader.

    Fix for MPP rb compression in d3plot when used with pre-decomposition

    Fixed MAT_236 for shells

    bug fix calculating enclsosure radiation view factors for
    axisymtric geometries.

    Fix for *MAT_ADD_THERMAL and solid element constitutive models, e.g.,
    type 3

    Minor fix for MAT_073 reading.

    Fixes for thermal option related to *LOAD_THERMAL_ELEMENT_…

    Fixes for laminated shell theory (materials 22, 54, 55, 76, 114)
    All Materials used 2x the correct weight on the on the top and bottom
    integration points for Labotto quadrature. For materials 76 and 114 with
    user defined integration, the unsorted material properties were used for
    calculating shear strain terms, fxi,fyi and zi1. Since the sort routine
    orders them top to bottom, this likely caused all the material properties
    to be flipped if the user input the points in the order from bottom to top.
    This would cause incorrect results if diffrerent properties were used in
    each layer unless Labotto quadrature was used.
    For materials 22 and 54, and 55, the unsorted material angles were used
    for calculating the shear strain terms, hi1, and hi2. For orthotopic
    material properties, the calculated hi1 and hi2 terms were therefore
    incorrect unless Labotto quadrature was used.

    Fix for load_thermal_element option for erroneous error check leading to
    termination.

    Fix for fitting of Ogden foam model due to out-of-range numbers

    Fix related to METALF when NDOF=3.

    Fix related to type 4 triangular shell and buckling.

    Fix for GCEOUT file

    bug fix for M136

    bug fix for AIRBAG_SHELL_REFERENCE_GEOMETRY

    Fix memory clobber for implicit solid spotwelds

    Fix for spotweld option to convert subset of beam elements.

    Bug fix for *control_forming_template

    Several MPP rigid-rigid contact:
    friction handling, force summation, and surface reorientation.

    Fix for load curve reading problem related to seatbelt shell elements.

    MPP modifications to bucketsort for AUTO_TIEBREAK contacts, to better
    handle very thick materials

    Fix for material type 61 which goes unstable for tet types 10 and 13.

    Update for handling 1000000 load curves efficiently.

    Fix for *CONSTRAINED_JOINT_TRANSLATIONAL_MOTOR not working correctly in MPP

    Fixed a bug in *LOAD_DENSITY_DEPTH if number of parts if more than 8

    Fix for surface force transducers for segment based contact. This memory bug
    could have happended when not all processors have 2 surface force transducers.

    Fix for material 36 with hardening rule 7 (3 load curves).

    Fix use of wrong variable in MPP d3part initialization.

    Fix truncation error for *MAT_123

    Fixed a segment based contact bug that caused the optional thickness on
    *PART_CONTACT to be ignored if shell thickness updates were active and no parts
    used the thickness scale factor on *PART_CONTACT.

    Fix problem in automatic tiebreak options 8/10/11 where the mass of the
    slave node was being used, but was not being passed, resulting in NANs.

    Fixed a bug in MAT_SPOTWELD_DAIMLERCHRYSLER when used with damage types 1
    and 2. The density of the material changed to a wrong value after damage
    initialization.

    Fix for joints in the presence of implicit-explicit switching.

    Fix for *MAT_MUSCLE related to small stepsize

    Fix for *DAMPING_PART_MASS related to velocity boundary conditions being
    affected by damping applied to deformable nodes with prescribed motion.

    Fix for *DAMPING_GLOBAL related to nodal points that have prescribed motion.
    This damping changes the applied displacements from the specified
    values. This fix corrects this problem for the nodes of deformable
    bodies.

    Use local rigid body accelerations for airbag pop option. Previously
    the global accelerations were used which is in conflict with the
    users manual’s instructions.

    Bug fix for selective mass scaling in conjunction with 10-noded tets

    Add MPP support for recent IOOPT option for intfor file.

    Fix problem of MPP reopening intfor file during adaptive problems.

    MPP fix for reorientation of surfaces with inconsistent normals

    Fix storage allocation for constrained_linear with 2000+ nodes.

    Fix for smooth contact problem related to undefined node set.

    Bug fixed for 2D axisymmetric EFG in centering the stress point.

    MPP fixes to output of d3part database

    Fix possible bug in mat 173 principal stress direction calculation

    Add option for alternative version of Mat 85 (does not affect existing models)

    Fix for adaptive remeshing for ESORT=2

    Fix MPP tied contact for implicit-explicit switching

    Fix uninitialized variable in MPP rigid-rigid contact

    Fix for thick shell type 26 to properly handle offset from midsurface.
    Warping stiffness must be active.

    Fix for thickness offset related to type 16 shell and warpage active.


    Fix for PRESCRIBED_ORIENTATION

    Fix flexible rigid body for initialization, rigid and flexible switching.

    Fix for eigenvalue problems with only solid elements and no rigid bodies.

    Fix for MAT_ARUP_ADHESIVE in *INCLUDE_TRANSFORM

    Fix for *ELEMENT_MASS_NODE_SET

    Fix for mat type 172 with shell type 16

    Fixed for *AIRBAG_HYBRID_CHEMKIN

    Fix: Internal energy is now computed for shell type 18.

    Fix bug at corners when multiple boundary conditions are used
    with SPH elements

    Fix for file SSSTAT in restart. Also we sperated the output interval
    of *DATABASE_SSSTAT_MASS_PROPERTIES and *DATABASE_GLSTAT

    Bug fix for ale interface force binary plot fsifor.


    Minor fix for MAT_100_DA with DG_TYP=3: Default for GFAD now 1.e-15
    (was 0.0 before, leading to no failure at all).

    A bug fix for mapping with symmtric condition


    Fix for Boundary Prescribed Orientation for Implicit.

    Fix for energy calculation in material model 122.

    Fix for *DEFINE_CURVE_FUNCTION: did not work for
    translational and rotational motors.

    Fix to damping when IGNORE is set to 1

    Fix for Brode loading and shell sets is now fixed.

    Bug fix for tiebreak contact option 11 with VDC damping and negative
    ncpu

    Added penalty formulation for treating contact between rigid bodies and
    the rigid road surface.

    Fix for format problem in DYNA.INC file related to *LOAD_PRESSURE_SHELL.

    Fixed type 9 beam spot weld failure. The moment term in the failure
    calculation may have used the wrong beam length since the wrong beam
    element ID was used. The 3-sheet calculation was OK. Therefore for
    models using 3-sheet welds, the bug may have not caused much trouble
    since the 3-sheet calc is used for an entire block of beam elements if
    any one of the beam participates in a 3-sheet weld.

    Bug fix for tiebreak contact options 10/11 with viscous damping VDC.

    Fix related to deformable to rigid switching, when the
    Inertial properties are specified for the merged body.

    MPP fix for rigid to rigid contact.

    Fixed related to table lookups in CONSTRAINED_
    JOINT_GENERALIZED_STIFFNESS.

    Fix related to inconsistencies between Madymo an ls-dyna force
    calculations for rigid to rigid contact using a force deflection curve.
    Energy is now conserved.

    Fix MPP explicit initialization for implicit joints

    Fix for possible memory clobbering when *RIGIDWALL_PLANAR and
    *PART_COMPOSITE are used together

    Fixed a problem with solid welds. Weld failure types 7 and 8
    use tied contact info to identify properties of the shells to which the
    welds are tied. It is possible for the tied contact to be on a different
    proceessor than the weld in which case the info cannot be found, so
    message passing was added to weld initialization.

    Fix for *INITIAL_AXIAL_FORCE_BEAM: resultant force was too high.

    Fixed output of two-pass adaptivity

    Fix related to implicit nonconvergence of materials 77, 177, and 178.

    Fix related to implicit consistency flag (ncpu<0)

    Fix for *ELEMENT_MASS_PART and shells: corrected mass calculation

    Fox for RBE3 with DOF’s release. Problem occurred when consistency
    option is active.

    MPP fix/change for better handling of adaptive constraints if they occur
    at decomposition boundaries AND they are involved in a tied interface.

    Fix handling of sense switches (sw1,sw2,…) for implicit.

    Fixed contact for Genoa material.

    Fix for jumps in sliding interface energy when adaptive steps occured.

    Bug fix for material 187.

    Fix for non working thinning for thick shell elements and material types 2, 22, 55, and 58.

    Fix for *SET_BEAM_GENERAL with the ALL option to exclude phony beams for
    springs and dampers if BEAM is set to unity on the DATABASE _BINARY_
    D3PLOT database.

    Fix for RBE3 constraints for MPP Explicit.

    Fix l2a problem related to output of optional joint energies

    Fixed problem with INCLUDE_TRANSFORM for material model 176.

    Fix for bug related to nonphysical stresses that develop soon after
    the calculation begins. Keyword CONSTRAINED_SHELL_TO_SOLID.

    Fix related to material type 120 related to FPE on selected platforms.
  • Killing LS-DYNA Jobs

    Running LS-DYNA jobs (either interactively or as a batch job) can be interrupted with sense-switch controls by creating files “d3kil”, “D3KIL” and “switch” in the running directory. This works as expetec without the use of any “jobid” definition. However, when using a jobid parameter either using *KEYWORD_ID or in the command line (jobid=jobname), LS-DYNA expects this jobid string to appear in the fiels such as “jobid.d3kil” or “jobid.D3KIL” or “jobid.switch” files in the running directory of the master node.

  • D3VIEW Update : LS-DYNA Examples Project Now Available for Public

    The LS-DYNA Examples Project , managed using D3VIEW, is now available for public usage.
    If you want to become part of the team to contribute to the examples set, you can send me an email at INFO at D3VIEW dot COM.

  • Effects of Initial Penetrations

    It is well known that the presence of initial penetrations can spoil the accuracy of the analysis. A few days ago, while working on ODB barrier, some strange spikes in energies was suspicious even with IGNORE turned on. To understand this, I simply did a simple shakedown and generated some 100 d3plots to capture the effects. After analyzing the results, the strange effects were attributed to the presence of initial penetrations. What is interesting is these small penetrations can introduce contact stresses in the structures and can propagate through them. Attached is a clip generated from the barrier study where the simulation was run with no external loads, body forces, and boundary conditions. You can see the source of initial penetrations and how they travel at the top of the barrier (cladding sheet).

    initial_penetrations.gif

  • Nice article on Inertia Tensors

    Came across this nice article (PDF, 101kb) about inertia tensors.