NE/Nastran 8.3

8 January, 2004

The new NE/Nastran 8.3 features new advanced dynamic solutions with over 50 additional customer driven enhancements.

NE/Nastran 8.3 features new advanced dynamic solutions, a more robust quad shell element, a new spot weld element, solver support for parallel processing, a faster Lanczos eigensolver, substructuring and model reduction, new aerospace and automotive productivity tools, and over 50 additional customer driven enhancements.

Additional features include Model Interpolation to allow mapping of data from one simulation mesh to another within the solver. The method can be used for 2D or 3D models with scalar or vector data such as temperatures from a heat transfer model or pressures from a CFD model mapped to a structural model. No alignment is required between the input data to be interpolated and the target mesh.

Improved solver performance is now provided through parallel processing support in the PCGLSS linear and eigensolvers. Typical performance increases with 2 processors are 30-50% for the PCGLSS linear and 15-20% for the PCGLSS Lanczos eigensolver. Support is now provided for substructuring and super element generation via the ASET reduction method. Reduced models may be exported using DMIG and combined with other models.

New advanced dynamic solutions include Direct Frequency Response for more accurate and efficient analysis of high frequency systems, adaptive time stepping in Direct Transient Response and Complex Eigenvalue Analysis for solving problems in acoustics, rotating bodies, and many other physical effects where damping or unsymmetric stiffness/mass is required. New elements include a spot weld element (CWELD) that allows a weld connection to exist at any position in a shell mesh thus significantly improving productivity when developing body-inwhite automotive models.

Enhanced Aircraft Specific Tools

  • Enhanced tension only nonlinear shell elements. The compression stiffness scale factor is now divided into x and y element directions and is panel width normalized for values greater than one. The format is similar to the effectiveness factors for shear panel elements.
  • Added PARAM, ADDNLTOQUADLOAD which when set to ON will add extensional loads in tension only quad and shear panel elements to adjacent line elements.
  • Enhanced effectiveness factors for extensional stiffness on shear panel elements. Separate effectiveness factors may now be specified for each panel edge.
  • Multiple individual load cases can now be run in a single non-linear solution by use of the NLSUBCREINIT parameter.

New Interpolation Tools

  • Added 3 new Case Control commands (TEMPINT, DISPINT, and LOADINT) for the generation of interpolated temperatures, enforced displacements, and loads (nodal to element pressures) in either 2D or 3D space. The input data does not need to be directly associated with the interpolated points. Enhanced Eigensolver Support.
  • Added Lanczos eigensolver support for buckling solutions.
  • Better performance when a large number of eigenvalues (> 100) need to be extracted.
  • Support for parallel processors for decomposition operations.
  • Added support for eigenvector filtering in DDAM solutions via the MODESET Case Control command. The command allows specifying which modes are to be used in a DDAM analysis by either a SET command, the TOP n modes based on modal effective mass, or modes above a specified PERCENT value.
  • Modal database reuse capability has been enhanced.

Improved MPC Processing and Handling of Improperly Defined RBE3 Elements

  • Significantly less memory required and faster processing of RBEi elements and MPC equations.
  • RBE3 element now supports rotational DOF at averaging grid points.
  • Added PARAM, AUTOFIXRIGIDELEM which when set to ON will automatically correct improperly defined RBE3 elements by adding rotational DOF to averaging grid points as needed to prevent rigid body motion.

New and Improved Solution Sequences

  • Added support for direct frequency response analysis (SOL 108).
  • Improved direct transient response analysis performance through a dedicated analysis module (SOL 109).
  • Added support for modal complex eigenvalue analysis with unsymmetric DMIG matrix input (SOL 110). The method uses either a subspace or Lanczos eigenvalue extraction to reduce the problem into modal space similar to modal response solutions.
  • Added PARAM, ADAPTTIMESTEP which when set to ON will use adaptive time stepping in linear direct transient response. The additional parameters are specified in fields 6 through 9 on the TSTEP entry.
  • New multi-mode PCGLSS solver has both the standard iterative and a new direct mode. The direct mode is not sensitive to element distortion and other effects that result in additional PCGLSS iterations and slower performance.
  • Support for parallel processors when the PCGLSS solver is selected. Typically 30% faster solution time when the direct preconditioner is selected.
  • Added complex iterative solver support for direct frequency response analysis (SOL 108). The complex VIS solver may perform better than the complex VSS solver for large TET10 element meshes.

Improved CQUAD4/CQUADR element.

  • A new, more robust QUAD4/QUADR formulation has been implemented that is better suited for solving curved shell problems. The element performs significantly better in difficult benchmark test problems including traditionally difficult Raasch hook and twisted beam cases.

New CWELD Element

  • Added support for spot weld elements via the CWELD and PWELD Bulk Data entries. The CWELD element can connect congruent as well as non congruent meshes and is supported in linear and nonlinear solutions. This element is particularly suited for simulation of spot welds in typical large scale automotive Body-In-White (BIW) finite element models.

Substructuring and Model Reduction Support.

  • Added static condensation/Guyan reduction support via the ASET and OMIT Bulk Data entries.
  • Reduced stiffness and mass matrixes may be exported to DMIG entries using the model parameter TRSLDMIDATA for use in other models.

Editor Enhancements.

  • Added NE/Nastran Editor custom xy-plotting. A point and component number may be specified for the generation of real-time custom xy-plots.

Enhanced .OP2 File Support

  • Enhanced Nastran .OP2 results file support included composite lamina and heat transfer results. Added PARAM, POST and OGEOM for compatibility with I-Deas, Patran, HyperMesh, and other pre and postprocessors. Model data is now optionally exported to the .OP2 file.

Additional Enhancements

  • Added PARAM, SLINEPENTOL and SLINEPROTOL which are used to specify the tolerances for adjusting initial penetration and protrusion errors on contact surfaces.
  • Added PARAM, SLINEPOSTOL which is used to control contact surface segment overlap.
  • Enhanced surface contact diagnostics.
  • Added support for output of subincremental results in nonlinear static solutions. When the INTOUT field on the NLPARM is set to ALL converged subincremental results will be output.
  • Enhanced surface contact parameters to increase performance by reducing contact segments generated.
  • Added the PTYPE field to the PCABLE property which allows the cable element preload T0 to be treated as either an initial load (default) or a constant value.
  • SET Case Control commands now allow real numbers as set ids.
  • Added rotational components to percent modal mass output.
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