10.2.2.1. DMAP Command

In NX/Nastran v5.0 and later version, in order that the RFI file which is contained CMS Analysis results is generated directly by NX/Nastran, it is necessary to modify or add the DMAP command in the input file for NX/Nastran.

At that time, because the stress/strain shapes cannot be generated in Stress Shape Interface, DMAP commands for the stress/strain shapes must be contained in this file. The outline for DMAP commands for that is as shown below.

$--------------------------------------------$
$ EXECUTIVE CONTROL
$--------------------------------------------$
SOL 103
TIME 3000
CEND
$--------------------------------------------$
$ CASE CONTROL
$--------------------------------------------$
TITLE= CMS analysis for RecurDyn
$*
SUPER = ALL
SEALL = ALL
$*
ECHO = NONE
METHOD = 100
$*
MBDEXPORT RECURDYN FLEXBODY=YES,FLEXONLY=YES,OUTGSTRS=YES,OUTGSTRN=YES
$*
GPSTRAIN=ALL
GPSTRESS=ALL
$*
SET 5 = 1 THRU 100
STRESS=5
STRAIN=5
$*
$*
OUTPUT(POST)
SET 6 = 1 THRU 100
$* Shell element : SURFACE
SURFACE 1 SET 6,FIBRE ALL,SYSTEM CORD 0
$* Solid element : VOLUME
$VOLUME 1 SET 6,DIRECT,SYSTEM CORD 0
$*
$--------------------------------------------$
$ BULK DATA
$--------------------------------------------$
BEGIN BULK
$-------$-------$-------$-------
PARAM   AUTOSPC YES
PARAM   GRDPNT  0
PARAM   WTMASS  1.0
PARAM   K6ROT   100.0
PARAM   BAILOUT -1
PARAM   RESVEC  YES
$
$-------$-------$-------$-------$-------$-------$-------
DTI     UNITS   1       KG      N       M       S
$
$ Extract Normal Mode
$-------$-------$-------$-------$-------$-------$-------$-------$-------
EIGRL   100     -0.01           10
$
$-------$-------$-------$-------$-------$-------$-------
SESET   1       2       THRU    10
SESET   1       12      THRU    110
SESET   1       112     THRU    120
SPOINT  80001   THRU    80010
SEQSET1 1       0       80001   THRU    80010
$
$-------$-------$-------$-------$-------$-------$-------$-------$-------
$ GRID/ELEMENT/Material/Property CARDS
$-------$-------$-------$-------$-------$-------$-------$-------$-------

The description of several DMAP Commands in detail is as follows.

Command	Description
SEALL = ALL	Generates and assembles all super elements
SUPER = ALL	Assign the subcase to all super elements and loading conditions.
METHOD = 100	Select the real eigenvalue extraction parameters.
MBDEXPORT RECURDYN FLEXBODY=YES, FLEXONLY=YES, OUTGSTRS=YES, OUTGSTRN=YES	Generate RecurDyn RFlex Input (RFI) file. Here, the grid point stress (OUTGSTRS) and the strain (OUTGSTRN) are output to the RFI file. If your version of NX Nastran is 6.1 or later, use this command. Note) If your version of NX Nastran is earlier than 6.1, use this following command. RECURDYNRFI FLEXBODY=YES,FLEXONLY=YES,OUTGSTRS=YES,OUTGSTRN=YES
GPSTRAIN=ALL	Output of grid point strain for all SURFACE and VOLUME commands.
GPSTRESS=ALL	Output of grid point stress for all SURFACE and VOLUME commands.
SET 5 = 1 THRU 100	Define a set which contains all of the element’s IDs.
STRESS=5	Output of stress for elements defined in Set 5
STRAIN=5	Output of strain for elements defined in Set 5
OUTPUT(POST)	Indicates the beginning of surface or volume commands.
SET 6 = 1 THRU 4086	Defines Set 6 as the same as Set 5 defined above.
SURFACE 1 SET 6,FIBREALL, SYSTEM CORD 0	Sets the surface for which strains and stresses are calculated. Here, direct stresses and strains are requested. Note) If solid elements are used in the mesh, the VOLUME command should be used instead, as shown below: VOLUME 1 SET 6,DIRECT,SYSTEM CORD 0
DTI UNITS 1 KG N M S	Defines the units of measurement to be used in FE software.
SESET 1 2 THRU 10 SESET 1 12 THRU 110 SESET 1 112 THRU 120	Defines interior nodes for the super element of the flexible component. This set should include all the nodes of the flexible body except the interface nodes.
SPOINT 80001 THRU 80024	Defines Scalar Point.
SEQSET1 1 0 80001 THRU 80024	Defines the generalized DOF of the super element
EIGRL 100 -0.01 10	Super element modal solution

To obtain the more accurate stress/strain recovery results for all animation frames after simulating a RFlex model, it is necessary to create a MDF file. If the user want to use the MDF file, refer to How to apply MDF file in NX Nastran, because DMAP Commands is different to upper commands.

Note

From the *.rfi file created in NX/Nastran 2019.2 version, CTRIA6 and CQUAD8 elements did not appear on the view. This is a problem that occurred on the NX, and can be solved by adding the command “NASTRAN SYSTEM(700)=1” to the data file.