NEi Nastran Engine Version 9.0 - New Features and Enhancements

NEi Nastran V9.0 is a major upgrade with over 50 customer driven enhancements.

Major features include support for automated internal superelement generation, enhanced nonlinear and dynamic solutions, improved solver and overall performance, a faster Lanczos eigensolver, support for XDB results neutral files, and new aerospace, maritime, and automotive productivity tools.

Several NEiEditor enhancements have been included such as a fully automated HTML report generator, shear flow plots, assignment plots, an enhanced X-Y plotting interface, and a secure DDAM data input form.

Performance Enhancements

	Faster nonlinear solver performance: Nonlinear solutions are now up to 2x faster
	Faster Lanczos eigensolver: Enhanced Lanczos eigensolver with over 4x faster performance on models where 50 or more modes are requested.
	Support for large laminate models: Improved performance for models with composite laminates and large numbers of plies where individual ply results are requested.
	Improved performance for models with CQUADi and CHEXA elements: Performance is improved for models with HEXINODE or QUADINODE set to ON or AUTO when ON is automatically selected and for models with tapered beam elements.
	Support for very large input files: Added support for model input files over 10 million lines in size.

	Better VSS solver: Enhanced VSS solver to automatically revert to out-of-core mode if unable to allocate memory for in-core solution.
	Added new directive for VSS solver: Added MINRAM directive to specify the minimum amount of memory for the VSS solver to use if an out-of-core solution is performed due to a failed attempt at an in-core one.
	Reduced memory requirements: Reduced memory requirements for direct transient response analysis.

Nonlinear Analysis Enhancements

	Enhanced surface contact: Enhanced nonlinear surface contact analysis improving both accuracy and performance as well as solution stability with complex contact scenarios.
	New surface contact forms: Added two new forms of surface contact: bi-directional slide and rough contact. Bi-directional slide prevents contacting regions from separating or closing but permits sliding (zero coefficient of friction). Rough contact allows separation and closure but does not permit sliding (infinite friction). Both types support symmetric and unsymmetric contact and are selected in field 8 on the BSCONP entry.
	Displacement based stiffness: Added displacement based stiffness updating for surface contact friction. When the friction condition is in the stick state the transverse stiffness for stick is adjusted to achieve the specified displacement.
	Enhanced nonlinear static solution restart: Added PARAM, MAXBISECTRESTART which when set to ON will permit restarting a nonlinear static solution which has terminated on a FATAL ERROR E5076: MAXIMUM NUMBER OF BISECTIONS PERMITTED REACHED error.
	Added better support for contact between a surface and a line or point: Added a THRU literal option for specifying grid point IDs on BSSEG Bulk Data entries. This option is useful when defining contact between a surface and a point or line.
	Added options for PARAM, MAXADJEDGE: Added an AUTO option for PARAM, MAXADJEDGE which sets a value of 50 if PARAM, SLINEMAXACTDIST is set to AUTO and zero if it is set otherwise.
	Labeling change for effective plastic strain: Changed labeling of effective plastic strain to EFF STRAIN-E for linear solutions and nonlinear solutions without material nonlinearity where von Mises strain is output. For nonlinear solutions with material nonlinearity the effective plastic strain is labeled EFF STRAIN-P.
	Added PARAM for material nonlinear update strategy: Added PARAM, NITERMUPDATE which controls the material nonlinear update strategy.
	Added PARAM for material nonlinear update strategy: Added PARAM, NITERMUPDATE which controls the material nonlinear update strategy.

	Added PARAM for surface contact update strategy: Added PARAM, NITERCUPDATE which controls the surface contact update strategy. The default AUTO setting uses an optimum value based on other nonlinear parameters.
	Added PARAM for nonlinear tolerances: Added PARAM, NLTOL which specifies default NLPARM Bulk Data entry EPSP and EPSW tolerances. Values range from 0 to 3 with 0 being the highest tolerance (accuracy) and 3 being the lowest (performance).
	Changed default value for PARAM, BISECT: Changed the default value for PARAM, BISECT from OFF to ON to improve accuracy in material nonlinear solutions.
	Enhanced the NLPARM and TSTEPNL entries: Added an AUTO option for the MAXITER field on the NLPARM and TSTEPNL Bulk Data entries. When MAXITER is set to AUTO or blank, an initial MAXITER setting of 40 is used and is automatically increased as the number of iterations approaches MAXITER if the solution is converging.
	Enhanced element initial strain: Enhanced shell and solid element initial strain for better solution stability. Initial strain input is now scaled based on the load scale factor for nonlinear static solutions.
	Added parameter for augmentation factor: Added PARAM, NLKDIAGMINAFACT which sets the minimum nonlinear static augmentation factor when PARAM, NLKDIAGAFACT is greater than zero.
	Added logarithmic interpolation: Added logarithmic interpolation for the TABLES1 Bulk Data entry.

Dynamic Analysis Enhancements

	Support for vibration fatigue analysis in random analysis: Added support for vibration fatigue analysis in random response solutions via the VIBFATIGUE Case Control command and the SNDATA Bulk Data entry. Output includes both life and damage results measures as well as the biaxiality ratio.
	Added invariant stress/strain results for random analysis: Added von Mises and optional maximum and minimum principal stress/strain results for random response via PARAM, RANDRESPINVLEVEL which when set to 1 will output von Mises stress or strain and when set to 2 will also include principal and max shear stress or strain and biaxiality ratio in frequency and random response solutions.

	Added bush elements results in random analysis: Added results output for bush elements in random response analysis.
	Multipoint constraint force output for random analysis: Added multipoint constraint force output for random response solutions.
	Added parameter for eigensolver restarts: Added PARAM, MAXEIGENRESTART which defines the permitted number of eigensolver restarts when an invalid shift scale is either externally defined or internally estimated. Also, added PARAM, EIGENSHIFTSFACT which specifies the shift scale multiplier used to increase the shift scale for an eigensolver restart.
	Added output for bush elements: Added viscous damping force output for bush elements in transient and frequency response solutions.

Heat Transfer Analysis Enhancements

	Enhanced surface contact: Modified surface contact in heat transfer to require an active contact element to be in contact for a conduction element to be generated.
	Initial condition temperature correction: In transient heat transfer solutions grid points with different initial condition temperature and enforced transient boundary temperature will now have the initial condition temperature corrected as well as issue an E5036 warning message. Previously, only a warning message was generated.

Case Control command correction: Removed the requirement for a TEMPERATURE(INITIAL) Case Control command to be specified in steady state heat transfer analysis when there are no temperature dependent materials specified.

Composite Analysis Enhancements

	Added Von Mises stress and strain output: Added von Mises strain output for linear solutions using EFF STRAIN-E measure when either STRESS or STRAIN is requested. Also added von Mises stress and strain using the EQUIVALENT STRESS and EFF STRAIN-E measures respectively for composite laminate individual ply results. These measures are available when either STRESS or STRAIN output is requested.
	Added new failure theory: Added a new composite laminate failure theory based on the Puck PCP criteria.
	Added automatic selection of core material type: Added ACS option on PCOMP Bulk Data entry for automatic selection of core material type (foam = FCS or honeycomb = HCS) for stability index calculations. FCS is selected automatically for isotropic materials and HCS for orthotropic materials.
	Added failure theory for individual ply results: Added failure theory used for composite laminate individual ply results data written to the FEMAP Binary Results Neutral File.
	Enhanced composites strength ratio support: Added support for strength ratio calculations for the LaRC02 failure theory.
	Enhanced failure theory: Added feature to revert failure theory used in composite laminate individual ply results from LaRC02 to Tsai-Wu if a non-unidirectional material is detected. PARAM, LARC02TSAITOL has been added to control the tolerance that triggers reversion based on the ratio of E1/E2, XT/YT, and XC/YC.

	Enhanced Hill failure theory: Modified how the Hill failure theory handles cases where one or both of the extensional allowables is different in tension versus compression. Previously, the sign of the interaction term was used to separately select whether to use the tensile or compressive allowable.
	Improved performance for laminates: Improved performance for models with composite laminates and large numbers of plies where individual ply results are requested.
	Added support for 3D orthotropic materials via the MAT12 entry: Added dedicated support for 3D orthotropic materials via the MAT12 Bulk Data entry (similar to the MSC MATORT).
	Added support for laminate solid elements: Added support for laminated solid elements. Both the CHEXA and CPENTA now support layered material definitions using the PCOMP Bulk Data entry. Either isotropic or 3D orthotropic materials can be specified. Output is similar to 2D laminated composite shells and includes in-plane and interlaminar stress, strain, and failure index data. Support is provided for all linear structural solution sequences.
	Added strain energy output: Added strain energy output for composite shell elements.

Element Enhancements

	Additional parabolic shell element support: Added support for parabolic shell elements via the CQUAD8 and CTRIA6 Bulk data entries.
	Automated generation of CWELD elements from existing bar elements: Added the WELDGENERATE Case Control command for the automated generation of CWELD elements from existing bar elements.
	Added switch from linear to parabolic shell elements: Added the SHELLEGRID directive which when set to ON converts all QUAD4/QUADR and TRIA3/TRIAR elements to QUAD8 and TRIA6 elements respectively.

	Additional bush element output results: Added bush element support to the grid point force balance output table in the Model Results Output File. Previously, only the individual elas element components were displayed.
	Enhanced export of data for tension-only quad elements: Enhanced tension-only quad element export of reverted element data via a new TRSLTOQEDATA directive. For each subcase CQUAD4/CQUADR and CSHEAR entries are written out to the Bulk Data Output File when the TRSLTOQEDATA directive is set to ON.

Superelements Enhancements

Added automated internal superelement capability: Added automated internal superelement generation and full data recovery for linear static, normal modes, and modal response solutions using Craig-Bampton CMS reduction techniques and a very easy to use yet robust user interface. Users can define regions of their model for individual superelement generation using standard Nastran SET commands and NEiNastran automatically generates internal superelements with automatic partitioning and full data recovery. Also supported are the standard SESET and SEELT Bulk Data entries as well as the SEID field on the GRID Bulk Data entry for defining superelements. The number of component modes is defined via PARAM, NCBMODE. Each internal superelement may be exported after generation to DMIG format via the EXTSEOUT Case Control command. User specified external superelements can be supplied via standard DMIG Case Control commands and Bulk Data entries and are automatically assigned to a superelement.

	SESET and SEELT Bulk Data entries added: SESET and SEELT Bulk Data entries have been added for superelement support.
	Added superelement generation via SET: Added superelement generation capability via the SELEMGENERATE Case Control command which generates superelements using standard output sets.

Other Enhancements

	Modified local coordinate systems for rigid elements and MPC equations: Modified how local coordinate systems are handled on rigid elements and MPC equations when connected to other rigid elements and/or MPC equations. Now the dominating local coordinate system will be used excluding the basic system unless only the basic system is specified.
	EIGR Bulk Data entry added: Added EIGR Bulk Data entry for controlling the subspace eigensolver. Support is also provided for eigenvector normalization based on a specified grid point.
	Added large field support: Added large field support for CORD1X Bulk Data entries.
	Added new option for PARAM, NDAMP: Added an AUTO setting for PARAM, NDAMP which uses 0.01 for all solutions except transient heat transfer where 0.3 is used.
	Added automated surface contact and surface weld generation: Added automated surface contact and surface weld generation via the CONTACTGENERATE Case Control command and the CONTACTGEN and CONTACTTOL model parameters. Support is also provided for export of generated BSCONP and BSSEG Bulk Data entries when the TRSLMODLDATA directive is set to ON.
	Modified model database file extension: Changed the model database default file extension from .DAT to .NDB to prevent conflicts with other applications which use the .DAT extension to define Nastran input files.

	New extension for the model input file: The Model Input File can now have a .DAT extension when specified on the Nastran command line.
	Added PARAM to correct automatically improperly constrained RBEi elements: Added PARAM, AUTOFIXRIGIDSPC which when set to ON will automatically correct improperly constrained RBEi elements by adding a CELAS element with stiffness defined by PARAM, KRIGIDELEM between the dependent grid point and the applied single point constraint.
	Added new directive to translate out CELAS entry: Added the TRSLRBSEDATA directive which when set to ON will translate out CELAS and GRID Bulk Data entries added when PARAM, AUTOFIXRIGIDSPC was set to ON and modifications were made.
	Added support for tabbed model input files: Added complete support for tabbed model input files.
	Enhanced surface contact weld elements: Enhanced surface contact weld elements with significant protrusion.
	Reduced surface contact weld elements: Reduced surface contact weld elements with significant protrusion.
	Added DMIGADD Case Control command: Added DMIGADD Case Control command which combines multiple DMIG matrixes into a single set which can then be referenced via K2GG, M2GG, etc. commands.
	Support for coupled mass matrix use: Coupled mass matrix formulation is no longer forced when a DMIG mass matrix is imported unless the matrix has off-diagonal terms. Previously coupled mass was used regardless.

Results Enhancements

	Added parameter to support analysis result output: Added PARAM, PARTGEOMOUT which when set to ON will output to the Model Results File mass and mesh properties by property type and identification number. Support will be provided later for output by group. This parameter is mainly provided to support analysis report output.
	Support for mass properties output: Added PARAM, PARTMASSOUT which when set to ON will output to the Model Results File mass properties by property type and identification number. Support will be provided later for output by group.
	Added Von Mises stress and strain output: Added von Mises strain output for linear solutions using the EFF STRAIN measure when either STRESS or STRAIN is requested. These measures are available when either STRESS or STRAIN output is requested.
	Added support for real element results data: Added .PCH PUNCH file support for real element results data.
	Support added for strain curvature output: Added support for strain curvature output via the STRCUR option on the STRAIN Case Control command.
	Case Control command modification: Modified RESULTLIMITS Case Control command to include a step set id field which allows individual time steps, frequency steps, etc. to be specified when determining results measure limits.
	PUNCH output format addition: Added PARAM, PCHFILEDBLEPRCS which when set to ON will output real data in PUNCH output using 15 decimal places versus 6 when set to OFF.

	Strain output for bush element: Added bush element linear strain output.
	Enhanced support for the RESULTLIMITS command: Added RESULTLIMITS command support for SUBCOM generated subcases.
	Enhanced the PURGE directive: The PURGE directive now deletes incremental FEMAP Binary Neutral Files generated when the INCRRSLTOUT directive is set to ON.
	Added new directive to generate Nastran binary results neutral file: Added the RSLTFILEMETHOD directive which defines the method used to generate the Nastran Binary Results Neutral File. The SINGLEPASS option is faster but may not be compatible with all post processors due to the way data blocks are sequenced. The MULTIPASS method will be slower but is typically more compatible.
	Added support for Nastran XDB results file: Added support for the Nastran XDB results file format through the RSLTFILETYPE directive when set to NASTRANXDB. The Nastran XDB format allows selective import of results into FEMAP and other post processors.
	Reduced results output: Reduced results output not specifically requested by the user.
	Enhanced xy-plot capability: Increased xy-plot capability. The previous XYDATAGENERATE limit of 50 grid points has been increased to 1000.

Editor Enhancements

Custom X-Y plotting of results:

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Users can click on the Create Plot icon after loading the results in the Model View and a dialog is displayed. Users can select output sets for the X-axis and results to plot for the Y-axis.

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Users can enter a node or element ID to plot, or can select the node or element with the mouse

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Users can then click a button for a Plot Preview. This is helpful because there may not be any data the user wants to save.

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When users close the Plot Preview, they are prompted whether to save the plot or not. If yes, the plot is saved and displayed in the Plots tree in the Model/Results pane.

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Alternately the user can click button for View/Save. The plot is displayed and automatically saved and displayed in the Plots tree.

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The plots are permanently saved in the .xyp file.

Display XY Plot Dialog Bar.

Custom settings defined for each individual plot:

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When the user double clicks on a displayed plot, a Custom Settings dialog bar is displayed. The user can select the desired settings for this plot.

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The user can also reset the Defaults if they want. The changed settings can be immediately previewed by clicking the Apply Settings button.

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When OK is clicked, the custom settings for this individual plot are saved (to the “xyp” file).

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When this plot is loaded again it reflects its custom settings.

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The user can click the Data button to save the XY data to the clipboard.

Custom Plot Settings Dialog Bar.

Improved highlighting feature:

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When the user clicks to highlight nodes or elements, a dialog is displayed on the side of the view.

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Elements or nodes can be specified by adding them to the list, or by selection with the mouse. When the user clicks OK, all the entities in the list are highlighted.

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In work: selecting entities by box selection with mouse.

Highlight Elements Dialog Bar.

Improved options menus in tree-like format:

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The setup dialog box has been re-implemented using a tree-control on the left side and property pages on the right side.

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When the user clicks a tree item the property page for the options for this item are displayed.

Tree Property Sheet Dialog for User Default Settings.

Added report writer:

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HTML format report can be generated after the users load the .fno file while some PARAMs are set to ON.

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The HTML report contains summary of the analysis. Other data includes group definition, contact definition, element initial distortion summary, applied load vector resultant, reaction load vector resultant, displacement data, peak displacement component, and stress result summary of the model.

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Users can add their own conclusion and modify the default summary and glossary list.

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Default images are generated for the HTML report, or users can go to “Default Setting” to setup their own image preference (see Figure 5).

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Users just have to click the “Generate Report” button and a wizard will come up to guide them to generate their reports (see Figure 6).

Default Settings for Report Generation

Report Wizard

Added shear flow vector plots:

•	The Editor now plots vectors and values representing the shear running load around the external edges of any group of shell elements.
•	The action to plot is controlled via a button icon.
•	The user must include Grid Point Force Balance in the output request.
•	The groups defined in the NEiNastran Modeler can now be retrieved by the Editor from the Neutral file. This allows the external shear flow of any component to be visualized.