NX Nastran 3 Release Guide

NX Nastran 3

New Features

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Summary of NX Nastran Release 3

This release includes important new capabilities that further extend the breadth and enhance the performance of NX Nastran. These capabilities include:

New NX Nastran Advanced Nonlinear Analysis-Solution 601

Alternate Method for Specifying Shell Thickness

New Option for Special Handling of Duplicate Grid Points and Coordinate Systems

Enhanced Processing for Min/Max Data in SOL 12 and 112

Ability to Export ADAMS Modal Neutral Files

New ISRR Method for Complex Eigenvalue Extraction

New Formulation for the CQUADR and CTRIAR Elements

Hierarchic Domain Parallel Normal Modes via Lanczos

Documentation Improvements

Miscellaneous Enhancements

2 NX Nastran 3 New Features NX Nastran Advanced Nonlinear Analysis-Solution 601NX Nastran Advanced Nonlinear Analysis is a new capability in this release. The solution is an integration of a well-established and highly regarded nonlinear solver, which creates the new solution sequence Solution 601.

With the addition of this new solver, NX Nastran can now handle a wider range of analysis problems with advanced capabilities. Using solution 601, you can now solve:

Models with large displacement and large strain conditions

Models with 3D surface-to-surface contact

Elastic-Plastic material models

Mooney-Rivlin hyperelastic material models

Gasket material models

Static and dynamic solutions

Example problems which can now be solved using solution 601:

Vehicle Crush Analysis:

3Description of vehicle crush analysis:

Performs crush analysis of car body model

Structure encounters large displacement and plastic deformations

Load applied as either force or displacement of contact surface

Materials included are elastic, plastic, and hyperelastic

Engine Gasket Seal Simulation:

Description of gasket seal analysis:

Simulates gasket seal between an engine block and cylinder head to verify that pressure will be contained

Analysis is typically performed by preloading the bolts to bring the gasket into contact with the cylinder head and block

An incrementing internal pressure load is applied

Structure has small displacement but hyperelastic deformation of the gasket material

4 NX Nastran 3 New Features Electronic Phone Drop Simulation

Description of phone drop analysis:

Simulates a cell phone dropping and impacting the ground

Contact is defined between the phone battery and the inside of the case, and between the phone exterior and the ground

Analysis is performed as a large displacement transient using the solution 601 analysis type 129

How to run a solution 601 problem:

To run a solution 601 problem, enhanced and new Executive Control, Case Control and Bulk Data Control commands are available. In the Quick Reference Guide, any commands created only for use in Solution 601 will have the text (SOL 601 only) next to the brief command description field. Some existing commands which can be used in a Solution 601 have special usage requirements or have been enhanced. These commands have an addition to the remark section labeled Remarks related to SOL 601. There are also commands whose use is the same as in other solution types so do not require any additional documentation. For a listing of all supported commands and detailed information on using Solution 601, please see the Solution 601 Theory and Modeling Guide. Also see SOL 601,N Executive Control Card in the Quick Reference Guide for general information on how to run SOL 601.

5The following examples have been provided in the install location NX_Nastran_Install_Path/nxn3/nast/tpl to demonstrate capabilities and to show the correct syntax for SOL 601 problems: gasket.dat, nlstat.dat, nltran.dat, panel2g.dat, sph_shell1a.dat, sph_shell1b.dat

Alternate Method for Specifying Shell ThicknessA new TFLAG field (field 13) has been added to the CQUAD4, CQUAD8, CQUADR, CTRIA3, CTRIA6, and CTRIAR element entries. The TFLAG field provides you with an alternate method for specifying the thickness of shell elements.

In previous releases, you could define shell element thickness by:

entering a single thickness value (T) on the PSHELL card to be used for all the corners of the element

individually specifying a different thickness for each corner of the element using optional fields on the element card

If you specified individual corner thickness values, the software ignored the PSHELL thickness value.

With the TFLAG option, you can specify the corner thickness values as relative thicknesses. NX Nastran will then calculate the thickness at a corner as the product of the relative thickness specified on the element card times the absolute thickness (T) defined on the PSHELL card.

Specifically:

If TFLAG = 0 or blank (default), the thickness is defined by the single thickness on the PSHELL, or if it exists, by the individual corner definitions on the element

If TFLAG=1, the membrane thickness becomes a product of the values of the element card and the thickness on the PSHELL card

The TFLAG option is particularly useful for performing design optimization analyses in which youre using thickness as a design variable.

The example shell_thick.dat has been provided in the install location NX_Nastran_Install_Path/nxn3/nast/tpl to demonstrate the correct syntax for the alternate shell thickness capability.

Membrane Thickness Ti T=

6 NX Nastran 3 New Features New Option for Special Handling of Duplicate Grid Points and Coordinate SystemsIn previous releases, if your model contained grid point cards with duplicate grid point IDs and/or coordinate system definitions (CORD1C, CORD1R, CORD1S, CORD2C, CORD2R, CORD2S), NX Nastran would report a fatal message and abort the solve.

With this release, however, a new system cell, DPBLKTOL, has been added to allow you to control how the software handles such duplicates. By default, the DPBLKTOL cell is turned off (or DPBLKTOL set to a value < 0) and models containing duplicate grid point IDs or coordinate system definitions still fail to solve. However, if you turn DPBLKTOL on (DPBLKTOL set to a value of 0 or greater), NX Nastran uses some logic to ignore one of the duplicates and proceed with the analysis.

Allowing a solve to proceed even if your model contains duplicate grid IDs and/or coordinate system definitions can be particularly useful when youre analyzing system models. For example, in some cases, you may need to build a series of component models and then import them into a single bulk data file. Instead of having to connect the individual components in the system model with rigid elements, you can now activate the DPBLKTOL option. If the grid point IDs you used to model the connections were coincident and identically labeled, NX Nastran will automatically join the models during the solve.

To use the DPBLKTOL option:

Set DBBLKTOL < 0.0 (default) to have the software abort a solve if a model contains duplicate GRID point IDs and/or coordinate system definitions.

Set DPBLKTOL=0.0 to have the software ignore duplicate GRID point IDs and/or coordinate system definitions and proceeds with the solve.

Set DPBLKTOL > 0.0 to specify a tolerance value that determines whether the software ignores GRID IDs and/or coordinate system definitions and proceeds with the solve.

With DPBLKTOL set to a value > 0, the software allows a model with duplicate grid IDs to solve if all the following conditions are met:

the coordinates of the duplicate GRID IDs are within the specified tolerance

only one (or none) of the duplicate cards has a defined local coordinate system

7 all cards are on the same superelement

If all the conditions are met, the software uses the GRID point card with a local coordinate system during the solve and ignores the other cards. If none of the cards has a defined local coordinate system, the software uses the first card and ignores the rest. If all the conditions are not met, the solve aborts with an error.

With DPBLKTOL set to a value > 0, the software allows a model with duplicate coordinate system definitions to solve if all the following conditions are met:

the coordinate system types are identical

the resulting coordinate system transformation matrices are identical

all coordinate system definitions are on the same superelement

If all the conditions are met, the software uses the first coordinate system definition and ignores the rest. If all the conditions are not met, the solve aborts with an error.

The example dup_grid_proc.dat has been provided in the install location NX_Nastran_Install_Path/nxn3/nast/tpl to demonstrate the new treatment of duplicate grids.

Enhanced Processing for Min/Max Data in SOL 12 and 112A new case control command, RMAXMIN, has been added in this release. You can use RMAXMIN to have the software search stress, force and displacement tables generated during a SOL 12 or SOL 112 for the minimum, maximum, or absolute value maximum result values.

With RMAXMIN, you can use the PRINT, PUNCH, and PLOT options to specify where the software should output the results. Use of PARAM POST will also send the results to your OUTPUT2 file. A new PARAM RMXTRAN has been added to allow the max/min data blocks to replace the transient output data blocks. You can also use a special DMAP alter to customize the input, output and contents of your.op2 file. The alter is documented under RMAXMIN in Chapter 4 of the NX Nastran DMAP Programmers Guide.

The example maxmin_proc.dat has been provided in the install location NX_Nastran_Install_Path/nxn3/nast/tpl to demonstrate how to correctly use RMAXMIN.

8 NX Nastran 3 New Features Ability to Export ADAMS Modal Neutral FilesThis release includes capabilities that allow for greater interoperability between NX Nastran and the MSC.ADAMS product. Beginning in this release, you can now write out an ADAMS modal neutral file (MNF) directly from NX Nastran. The MNF contains the reduced order matrices from the results of your NX Nastran solve. You can then import the MNF into ADAMS and use the results to represent a flexible component in a multi-body, dynamics analysis. You can use this capability when youre running a non-restart SOL 103 (SEMODES) analysis.

This direct MNF export capability streamlines the process of creating flexible components from FE models, making it possible for you to obtain more accurate results from multi-body simulations. Previously, importing Nastran results into ADAMS involved a two-step process of first using DMAP to export the results data from your.op2 file and then running a separate utility to translate the data into the correct MNF format.

The example mnf_link.dat has been provided in the install location NX_Nastran_Install_Path/nxn3/nast/tpl to demonstrate the export of an MNF from NX Nastran.

New ISRR Method for Complex Eigenvalue ExtractionA new method for complex eigenvalue extraction, the Iterative Schur-Rayleigh-Ritz Method (ISRR), is now available. ISRR is an additional complex eigenvalue extraction method which works well on sparse matrices, confines the search region to a circle centered on the origin of the complex plane, and provides some reliability that all modes within the circle have been found.

As a consequence, this new method finds modes in the proximity of the origin. If a large number of modes is required, or if a frequency shift is needed to find modes at a large distance from the origin, use the block Lanczos method instead.

With the addition of the ISRR method, there are now four choices for complex eigenvalue extraction available: Complex Lanczos, ISRR, Inverse Power, and Hessenberg.

The ISRR method can be selected by using ISRR in the method field on the EIGC card. Its use is similar to the Lanczos method, except when a continuation card is used. The ISRR continuation card is different than the other methods and is defined under the EIGC card heading in the NX Nastran Quick Reference Guide.

9The example isrr_sample.dat has been provided in the install location NX_Nastran_Install_Path/nxn3/nast/tpl to demonstrate how to correctly run a problem using the ISRR Method.

New Formulation for the CQUADR and CTRIAR ElementsA new CQUADR/CTRIAR element formulation has been implemented in this release. This new formulation, which is now the default for the CQUADR and CTRIAR elements, still has the original appeal of a real stiffness in the drilling degree of freedom but lacks the limitations of the old CQUADR/CTRIAR. The following limitations which existed in the previous CQUADR/CTRIAR have now been removed:

Membrane-bending coupling is now supported by CQUADR/CTRIAR

The differential stiffness matrix is computed for Solution 105 (Buckling analysis) and can also be used with Solution 103 (Normal Modes)

Steady-State, Transient, and Nonlinear Heat Transfer are now supported by CQUADR/CTRIAR

Layered stress/strain output for composite laminate materials is now available

Shell offsets was implemented with the new CQUADR/CTRIAR

The following mass matrices are used with CQUADR/CTRIAR:

Lumped only the translational masses are computed

Coupled mass both the translational and rotational masses are computed

Solution 200 now supports shell offsets, material ply angle and material ply thickness for the CQUADR/CTRIAR

Consistent surface loads have also been implemented for the new CQUADR/CTRIAR

By eliminating these limitations, the CQUADR/CTRIAR are now practical element choices for many analysis problems.

The new CQUADR/CTRIAR formulation is recommended over the old, however, a new system cell 370 is available for reverting back to the old formulation.

10 NX Nastran 3 New Features

Tes

Pat

Pat

StraExt

StraBen

StraBen

StraBen

StraBen

Cur

Cur Setting the system cell 370 to 0 (default) selects the new CQUADR/CTRIAR membrane formulation.

Setting the system cell 370 to 1 selects the older, limited CQUADR/CTRIAR formulation.

ExamplesOver the years, a number of models have been used to provide benchmark solutions in order to better understand the relative performance of various shell element formulations. A standard set of test cases, known as the MacNeal-Harder tests, have been used to gauge the accuracy of a finite element. In short, they have attempted to study the effects of different loading conditions on the various dynamics (membrane, bending, in-plane shear, out-of-plane shear, etc.) when the elements are perfectly formed and not so well formed (e.g. warped, skewed).

The following table compares the new CQUADR, old CQUADR and the CQUAD4 using MacNeal-Harder test cases which consist of in-plane and out-of-plane loading and behavior:

MacNeal-Harder Test Case Summary

Element Loading

t Case DescriptionIn-Plane Loading

Out-of-Plane Loading

Element Shapes

New QUADR

Old QUADR

CQUAD4

ch Test X Irregular A B A

ch Test X Irregular A B A

ight Beam, ension

X All A,A,A A,A,B A,C,C

ight Beam, ding

X Regular A A A

ight Beam, ding

X Irregular B,B A,A F,D

ight Beam, ding

X Regular A A A

ight Beam, ding

X Irregular A,A A,A A,A

ved Beam X Regular A A D

ved Beam X Regular B B B

11

Rec(N=

Sco(N=

Sph

Raa

Raa

For

R -

A: E

B: E

C: E

D: E

F: EMost if not all commercial shell elements perform reasonably well under membrane loading. However, its worth pointing out that the new CQUADR (and to a certain extent the old CQUADR) performs much better under membrane loading than the CQUAD4 when the element is shaped like a trapezoid or parallelogram. For more information, see Finite Elements: Their Design and Performance, by Richard H. MacNeal, Marcel Dekker Inc., 1994, p 11.

Although there are membrane behavior and performance differences between finite elements in certain classes (i.e. linear quadrilateral), the largest differences are in the way the bending and transverse shear behavior is handled (out-of-plane loading). The question of which elements perform best under a variety of loading configurations for flat, singly curved, and doubly curved surfaces is shown below for a number of test cases.

For these bending test cases, the mesh is refined to show the rate of convergence. The problems studied are all linear static test cases and are part of the MacNeal-Harder test suite. All the results (displacements at a particular node) were

tangular Plate 4)

X Regular B B B

rdelis-Lo Roof 6)

X X Regular B B B

erical Shell (N=8) X X Regular B C A

sch Hook (1x9) X Regular B B B

sch Hook (20x136) X Regular A A A

tests 3-8: All (R,T,P); Regular (R); Irregular (T,P)

Rectangular, T - Trapezoidal, P- Parallelogram Shaped Elements

rror is less than or equal to 2%

rror is between 2% and 10%



rror is greater than 50%

12 NX Nastran 3 New Features normalized, where 1 is the correct answer. Five mesh densities were used to show the rate of convergence. The number of elements on the X-axis refers to the number of elements per edge.

The plots shown in the following examples describe the behavior of three element formulations:

New CQUADR (new default CQUADR in NX Nastran 3)

Old CQUADR (default NX Nastran 2 CQUADR)

CQUAD4

13Thin and Thick Rectangular Plate

Thin and Thick Rectangular Plate Model Description: Flat plate simply supported on all edges, uniform pressure loading over entire face, deflection result at plate center.

Thin Plate Results (t/L=.01): Demonstrates that CQUADR converges comparably with the CQUAD4 for a flat thin plate model under bending loads.

Thin Rectangular Plate

0

0.25

0.5

0.75

1

1.25

0 5 10 15 20 25

Mesh Density (elements per side)

Norm

aliz

ed D

ispl

acem

ent

New CQUADROld CQUADRCQUAD4

14 NX Nastran 3 New Features Thin and Thick Rectangular Plate (cont.)

Thick Plate Results (t/L=.1): Demonstrates that CQUADR converges comparably with the CQUAD4 for a flat thick plate model under bending loads.

Thick Rectangular Plate

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 5 10 15 20 25


Norm

aliz

ed D

ispl

acem

ent


1530 Degree Skewed Plate

30 Degree Skewed Plate Model Description: Flat plate simply supported on all edges, uniform pressure loading over entire face, deflection result at plate center.

30 Degree Skewed Plate Results: Demonstrates that the new CQUADR outperforms the CQUAD4 for coarse meshes with skewed elements.

30 Degree Skewed Plate

0

0.5

1

1.5

2

0 2 4 6 8 10 12


Norm

aliz

ed D

ispl

acem

ent


16 NX Nastran 3 New Features Scordelis-Lo Roof

Scordelis-Lo Roof Model Description: Singly curved surface, 1/4 symmetry model, supported by rigid diaphragm on outer cylinder edges, gravity loading which results in both in-plane and out-of-plane element loading.

Scordelis-Lo Roof Results: Demonstrates that the CQUADR performs comparably to the CQUAD4 for a singly curved surface with uniform gravity loading.

Scordelis-Lo Roof

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 2 4 6 8 10 12


Norm

aliz

ed D

ispl

acem

ent


17Pinched Cylinder

Pinched Cylinder Model Description: Singly curved surface, 1/4 symmetry model, supported by rigid diaphragm on outer cylinder edges, concentrated load which results in both in-plane and out-of-plane element loading.

Pinched Cylinder Results: Demonstrates that CQUADR performs comparably to the CQUAD4 for a singly curved surface with concentrated loading.

Pinched Cylinder

0

0.2

0.4

0.6

0.8

1

1.2

0 2 4 6 8 10 12


Norm

aliz

ed D

ispl

acem

ent


18 NX Nastran 3 New Features Hemispherical Shell

Hemispherical Shell Model Description: Doubly curved surface, 1/8 symmetry model, concentrated loading conditions.

Hemispherical Shell Results: Demonstrates that the CQUAD4 converges faster than the new CQUADR for doubly curved surfaces, yet the new CQUADR shows improvements over the old CQUADR.

Hemispherical Shell

0

0.2

0.4

0.6

0.8

1

1.2

0 2 4 6 8 10 12


Norm

aliz

ed D

ispl

acem

ent


19Hierarchic Domain Parallel Normal Modes via LanczosThe new Hierarchic Domain Parallel Normal Modes (HDMP) solution via Lanczos combines two existing techniques of Distributed Memory Parallel (DMP) processing: partitioning of the geometry and segmentation of the frequency into discrete domains. While the geometry partitions are solved across multiple processors, the frequency segments are also solved in parallel across the same set of processors. The advantage is a much faster eigenvalue solution time for very large models.

Although each processor is working on its own partition of the geometry, it communicates with the others in regards to the boundary. Once the solution is complete, the eigenvalue results are merged together, thus creating single results files for import into a post processor.

The user inputs for HDMP are similar to that of the geometry DMP in that the number of processors is still specified with the existing dmp keyword. In order to define the number of frequency segments, the new keyword NCLUST has been created. The number of geometry partitions is defined as the number of processors (DMP) divided by the number of frequency segments (NCLUST). This result must be an integer. The following table highlights these user inputs:

This new technology is available for SOL 103 only. You must use the EIGRL card, not the EIGR card, and both Fmin and Fmax must be specified. Fluid grids, disjoint structures and superelements are not permitted. In order to improve the balance of the frequency domain decomposition, the existing ALPHA tuning value of the EIGRL continuation card may be used.

It may be possible that a problem is not large enough to be partitioned, in which case a message is printed and a serial execution is done. Running with dmp=1 will also result in a serial execution.

When running on a cluster of multiprocessor workstations, it is recommended to set NCLUST to the number of workstations. The dmp value should then be NCLUST multiplied by the number of processors per workstation. Only homogeneous workstation environments are supported.

Keyword Definition

DMP Number of processors (integer).

NCLUST Number of frequency segments, which should equal the number of clusters available (integer).

DMP/NCLUST Number of geometry partitions, result must be an integer.

20 NX Nastran 3 New Features See Running Distributed Memory Parallel (DMP) Jobs in Chapter 4 of the NX Nastran Installation and Operations Guide for more information.

Documentation ImprovementsThis release includes a number of changes and improvements to the NX Nastran documentation set. These changes mark the initial stage in what will be an ongoing, multi-release effort to improve the content, structure, accuracy and usability of the Nastran documentation.

Our focus in this initial release has been on improving Nastran documentation that describes the general use of the software. An in-depth analysis of the documentation revealed a very high degree of topic/content overlap between the Reference Manual, the Linear Static Analysis Users Guide, and the Getting Started Guide.

We have:

consolidated the information on the general use of NX Nastran from the Reference Manual, the Linear Static Analysis Users Guide, and the Getting Started Guide into the new NX Nastran Users Guide. The NX Nastran Users Guide is designed to be a comprehensive source of information on creating and solving models with NX Nastran.

created a new NX Nastran Element Library. This book serves as a reference manual for the available elements within NX Nastran.\

created a new guide called the NX Nastran Basic Nonlinear Analysis Users Guide to cover solutions 106 and 129. The material for this guide came largely from the section on nonlinear analysis from the Special Topics section of the old Reference Manual.

Miscellaneous EnhancementsFatal Error for RBE3 with Unconnected Independent Grid PointIf an RBE3 references an unconnected, independent grid point, it is typically an unintended modeling error. Previously, if you turned on AUTOSPC, the software would automatically restrain an unconnected grid point. The restrained degree of freedom would be listed in the F06 file along with other degrees of freedom restrained by AUTOSPC. In many cases, you may not have noticed such AUTOSPC messages, thus causing significant errors in your solution results. If

21AUTOSPC was turned off, a singularity exists message would be written to the F06, but the solve would have nevertheless continued and also possibly given poor results.

Beginning in this release, NX Nastran will by default perform a check early in the solution to see if any of an RBE3s independent grid points are unconnected. If the software detects such a condition, it now issues a fatal message and aborts the solution.

The new RBE3 check can be modified so only a warning is issued and the solution continues when unconnected grids are found by specifying the following on the nastran data line:

nastran system(409)=1

The check for an unconnected node on an RBE3 is not performed for a superelement or dmp solution since an RBE3 in one superelement could be connected to another superelement.

The example rbe3_error.dat has been provided in the install location NX_Nastran_Install_Path/nxn3/nast/tpl to demonstrate how NX Nastran will error when an RBE3 with an unconnected independent grid exists.

Enhanced Residual Vector Response CalculationWhen residual vectors are used in a SOL 112 modal transient analysis, it is possible for the physical response to be incorrectly calculated because of an improper contribution from residual vector modes. The residual vector modes are calculated based on deformation from a static loading and are intended to only supply static effects. The residual modes have a calculated frequency that are always higher than the normal modes and thus are appended at the end of the normal modes. Physically, the residual mode frequencies are meaningless.

In NX Nastran, the residual vector modes are treated the same as normal modes. Thus if the frequency content of the loading falls in the frequency range of the residual modes, they may become dynamically excited, which can lead to incorrect results.

A new parameter RESVALT has been created to avoid this situation.

The default for the RESVALT parameter is NO, causing SOL 112 to work like it always has.

When RESVALT is set to YES, the residual vector mode will not have a dynamic contribution to the physical response.

22 NX Nastran 3 New Features Output of Stress and Force Results for SORT2 FormatYou can now write elemental results (stress, strain and force) in SORT2 format to the .op2 file for SOL 111 (modal frequency response) and SOL 112 (modal transient results).

The example sort2.dat has been provided in the install location NX_Nastran_Install_Path/nxn3/nast/tpl to demonstrate the SORT2 output format.

Component Mode Reduction of Residual Structure Command ModificationsHow you specify eigenvalue parameters for a component mode reduction of a residual structure (CMR of RS) has been changed. Previously the METHCMRS parameter you used for eigenvalue method selection. Now the creation of a new case control card, RSMETHOD, makes the method selection cleaner and provides a more understandable setup for solution. For this release, METHCMRS has been removed from the documentation, but when used in a solution will still be recognized. The plan is to phase the METHCMRS completely out in the next release of NX Nastran, thus it will no longer be supported.

Because the alternative methods CMR of RS and Residual Vector are superior to the old Generalized Dynamic Reduction (GDR) method, we no longer support GDR. This means that the DYNRED case control and bulk data cards are no longer supported.

To invoke an o-set or v-set eigen solution of the residual, you now use the RSMETHOD case control command. See the RSMETHOD case control command in the quick reference guide for input specifications. Other details related to the operation of the new RSMETHOD case control command are:

RSMETHOD is only valid if it appears in the residual structure subcase. If it appears in any other subcase it will be ignored and a warning will be issued.

If RSMETHOD and METHCMRS are used together in this release of NX Nastran, RSMETHOD will take precedence.

There is no default for RSMETHOD. Thus, if QSET is defined for a CMR of RS solution and RSMETHOD does not exist in case control, a component mode reduction will not be performed.

An example case control with the new functionality for CMR or RS is given below. In this example, subcase 101, which defines the residual structure solution, uses the new case control command RSMETHOD. The presence of RSMETHOD in this

23subcase invokes an eigen solution on the o-set or v-set (as defined by ASET, BSET and/or CSET cards) of the residual structure. RSMETHOD specifies the EIGR or EIGRL card to be used for the eigen solution. The METHOD card specifies the eigen parameters for the final system eigen solve.

SOL 103 $ SE MODAL FREQUENCY RESPONSE ANALYSISCEND$SET 100 = 0SEALL = ALL$SUBCASE 11SUPER = 10LABEL = SUPERELEMENT 10METHOD = 10$SUBCASE 61SUPER = 60LABEL = SUPERELEMENT 60METHOD = 60$SUBCASE 101SUPER = 0LABEL = RESIDUAL STRUCTURESPC = 1METHOD = 101 $ METHCMRS = 102 $ $$BEGIN BULK$$ SE 10 EIGEN CALCULATION

$SESET 10 2 3 4 5SPOINT 100001 THRU 100003SEQSET1 10 0 100001 THRU 100003EIGRL 10 0.0 3 1$$ SE 60 EIGEN CALCULATION$

24 NX Nastran 3 New Features SESET 60 12 13 14 15SPOINT 600001 THRU 600003SEQSET1 60 0 600001 THRU 600003EIGRL 60 0.0 3 1$$ SE 0$SPC1 1 2 1 16$$$ SYSTEM MODE CALCULATIONEIGR 101 MHOU 9$$$ CMR OF RS EIGEN CALCULATIONASET1 2 9 10$$ o-set or v-set EVPSPOINT 1000001 THRU 1000007QSET1 0 1000001 THRU 1000007EIGRL 102 0.0 7$ ......

NX Nastran Version Stamp Now Written to OP2 FilesA header is now written to the first line of the OP2 file to show which version of NX Nastran created the file. The 8-character header format is NX3.0 . The software writes the version stamp by default. However, you can turn the version stamp off by specifying system(407)=1 (or any non-zero value) on the nastran data line (usually the first line in the bulk data file). For example:

nastran system(407)=1

Automatic Processing of Dependent and Independent DOF for Rigid Elements, Constraint Elements and MPC EquationsIn previous releases, Nastran required you to select independent and dependent dof when creating rigid elements, constraint elements and MPC equations. This can be tedious for models with large numbers of contraints.

The parameter AUTOMPC is now available to eliminate the need to keep track of dependent and independent dof.

25 AUTOMPC=NO (Default), solution will work the same as it always has.

AUTOMPC=YES specifies that the m-set dofs are to be automatically selected by the software rather than the m-set values specified in the MPC or element (RBE*,RBAR,RROD,etc.) bulk data definition.

AUTOMPC will be set to NO automatically during a p-element analysis with local coordinate systems or a rsscon element, and in a design analysis (SOL 200) with dvgrid data.

You should avoid using the AUTOMPC option in models with rsscon elements connected to cpenta elements.

If an RBE3 element contains UM information on m-set data, those dof will be used in the m-set.

26 NX Nastran 3 New Features

Summary of NX Nastran Release 3NX Nastran Advanced Nonlinear Analysis-Solution 601Alternate Method for Specifying Shell ThicknessNew Option for Special Handling of Duplicate Grid Points and Coordinate SystemsEnhanced Processing for Min/Max Data in SOL 12 and 112Ability to Export ADAMS Modal Neutral FilesNew ISRR Method for Complex Eigenvalue ExtractionNew Formulation for the CQUADR and CTRIAR ElementsExamples

Hierarchic Domain Parallel Normal Modes via LanczosDocumentation ImprovementsMiscellaneous Enhancements

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Documents

NX Nastran 3 Release Guide