LS-DYNA R7.1.1 (R7.88575) released

New version of LS-DYNA is released for all common platforms.

Release notes for Version R7.1.1.

Herein are summarized most of the new features, enhancements, and significant corrections made since the release of version R7.0.0. These notes are arranged by topic.  Understand that in many cases, a particular note may have applicability to multiple topics, but in the interest of brevity, each note is listed only once and under only one topic heading.

New Features – General
Add new blockage option for vents in *AIRBAG_PARTICLE:
blockage considered.......................
.eq.0: no
.eq.1: yes
.eq.2: yes, exclude external vents
.eq.3: yes, exclude internal vents
.eq.4: yes, exclude all vents
  • In *AIRBAG_PARTICLE, the porosity and vent blockage option was not treated correctly in shared nodes under MPP and so the bag behavior was sensitive to the number of cores.  This source of MPP variation has been eliminated.
  • Add option in *CONTROL_CPM to consider CPM in the time step size calculation.
  • When using *AIRBAG_PARTICLE with IAIR=2, user should keep mole/particle similar between inflator gas and initial air particles to ensure the correct elastic collision. If different by more than 10%, code will issue warning message and provide the suggested initial air particle number.
  • Fix a conflict in *MAT_FABRIC when FORM=14 is used with the negative ID for unload curves, and the Anagonye and Wang porosity equation for airbag leakage area on *MAT_FABRIC is being used with a *AIRBAG_WANG_NEFSKE control volume. The conflict caused a bad venting calculation leading to NaN pressure.
  • Boundary
  • Implement splitting-pinball contact, Belytschko & Yeh (1992, 1993). This new contact option is invoked by setting SOFT=2, SBOPT=3 and DEPTH=45.
  • A penetration check method based on LS-PrePost version 4.0 is implemented for the new bilinear-patch-based contact, SOFT=2, DEPTH=45 & Q2TRI=0. The new method provides more accurate intersection information when Q2TRI=0.
  • Correct the contact type for MPP+185 error message.
  • Fix incorrect *CONTACT_AUTOMATIC…TIEBREAK interface forces if OPTION=4 and PARAM=1 and viscous damping coefficient, VDC>0.0.
  • Fix intermittent seg fault when using *CONTACT_FORMING_…_SMOOTH in SMP with ncpu>1.
  • Fix incorrect numbering of last intfor file (*DATABASE_BINARY_INTFOR).
  • Fix input error when SSTYP=6 in *CONTACT and there are >9999 parts in the part set defined in SSID.
  • Fix seg fault problem on some platforms when using *CONTACT_NODES_TO_SURFACE with FS=2.0 and in optional card B or in *CONTROL_CONTACT.
  • Fix contact instability when contact thickness, OPTT, is specified in *PART_CONTACT. Contact instability may occur if the merged nodes of shells have large differences in shell thicknesses.
  • Add warning message, INI+364, that erosion has been enabled when *CONTACT_ERODING is used.
  • Fix contact thickness for beam types 9, 11 and 12.
  • Add support for birth time for *CONTACT_2D_AUTOMATIC_TIED.
  • Fix MPP rcforc output for *CONTACT_2D_AUTOMATIC.
  • Fix SMP and MPP segment based contact when there are thick shells in contact and also solid element form -1 or -2 in the data.  The contact was assuming contiguous connectivity data for the solids and thick shells but this assumption does not work when there are solid form -1 or -2 elements.
  • Fixed a serious MPP segment based contact error that occurred when shell element formulation 25, 26, or 27 was used. The error caused memory corruption.  This error was a problem between revisions 78150 and 84870.
  • Improve the segment based single surface contact search for thick segment pairs that are too close together.  The code was not working well with triangluar segments. This change affects models with shell segments that have thickness greater than about 2/3 of the segment length.
  • Fix *CONTACT_2D_AUTOMATIC_TIED and …_TIED_ONE_WAY in two ways. First, the positioning of slave nodes that are offset from the master surface was not done with sufficient accuracy and the offset distance could change a little. Second, it was possible for master nodes constrained by SPC’s to move.
  • Fix an MPP segment based contact error that occurred for 2-surface contact in both the initial penetration check and the periodic intersection check.
  • Enable segment based quad splitting options to work when shell sets or segment sets are used to define the surface that will be split.  This is really a bug fix because there was no check to prevent this and the result was writing past the allocated memory for segment connectivites.
  • Fix the detailed searching in segment based contact when edge extensions are turned off. The search was failing to detect some penetration soon enough to account properly for thickness offsets when one segment is thick and the other thin.  This will change results when SHLEDG=1 or when DEPTH>=23 for which edge extensions are always turned off.
  • Fix two bugs releated to 2D automatic tied contact.
    • When the stiffness scaling was determined by part stiffness and dimensions (ISTIFF=1, default for implicit), the tied contact created NaN’s which destroyed the solution.
    • Also fix the IGAPCL option to close constraint gaps when R-adaptive remeshing is active.  Gaps were allowed to grow during remeshing.
  • Fix an apparent memory error in the segment based contact surface-to-surface bucket sort that could result in a memory overrun.
  • Fix *DELETE_CONTACT_2DAUTO when the contact interfaces did not have sequential ID numbers that begin with 1.
  • For *CONTACT_2D_TIED and *CONTACT_2D_TIED_ONE_WAY, enforce penalty constraints if either side of the constraint belongs to a rigid body.
  • Improve convergence in implicit for *CONTACT_TIED_SHELL_EDGE_TO_SURFACE_BEAM_OFFSET.
  • Fix for OPTION=7 of *CONTACT_AUTOMATIC_…_TIEBREAK. The failure equation adopted from the paper of Lemmen and Meijer was wrong. This is now corrected in the code and in the manual.
  • Correct “out-of-range forces” problem with *CONTACT_AUTOMATIC_…_TIEBREAK, OPTIONs 7 and 10. Only MPP.
  • For *CONTACT_AUTOMATIC_…_MORTAR, the contact thickness is now consistent with other automatic contacts, i.e., thickness on *PART_CONTACT overrides the thickness on *CONTACT_…, which in turn overrides the physical thickness
  • For *CONTACT_…_MORTAR, the bucket sort is made much more efficient resulting in significant speedup in large scale contact simulations
  • For *CONTACT_AUTOMATIC_…_MORTAR, the mortar contact now supports contact with the lateral surface of beam elements
  • Fix MPP segmentation fault in *CONTACT_SLIDING_ONLY in case some of the nodes involved have SPCs.
  • If slave thicknesses are turned on for contact entities, include beam thickness as well as shell thickness.
  • On *CONTACT_…_MORTAR, IGAP.GT.1 stiffens the mortar contact for large penetrations. The mortar contact has a maximum penetration depth DMAX that depends on geometry and input parametersr; if penetration is larger than this value the contact is released. To prevent this release, which is unwanted, the user may put IGAP.GT.1 which stiffens the behavior for penetrations larger than 0.5*DMAX without changing the behavior for small penetrations. This should hopefully not be as detrimental to convergence as increasing the overall contact stiffness.
  • Turn off normal check for *CONTACT_DRAWBEAD when ORIEN=4 in *CONTROL_CONTACT.
  • Constrained
    Frequency Domain
    Discrete Element Method
    Isogeometric Elements
    Electromagnetic Solver EM
    Incompressible Flow Solver ICFD
    Compressible Flow Solver CESE
    Chemistry Solver