Abaqus to Nastran Conversion Mapping

The Abaqus to Nastran conversion uses an open conversion scheme; you can specify different mappings in the configuration file.

Care has to be taken so that the element and property mappings are consistent. A valid mapping scheme is provided in the ConfigurationFile.txt file. This document explains the scope and limitations of the mapping scheme.

Elements

Elements have two basic attributes – configuration (or config) and type. The "config" defines the basic geometrical shape of an element. For example, tria3 configuration is a 3 node triangular element and hexa8 is an 8-node hexahedral element. The "type" defines the solver specific element type of a particular configuration. For example, the 4-node quadrilateral (quad4) element in Abaqus can be any of the following types: S4, S4R, M3D4, R3D4 and so on. The Element Types panel shows all supported element configurations and their types for a user profile.

For a specific configuration, you can map any supported Abaqus element type to any supported Nastran element type, or vice versa. For example, for an Abaqus to Nastran direction, several 2-noded element configurations such as spring, rigid, bar2, rid, and so on are supported. Because all of them are 2-noded elements, conversion across these configurations is also allowed for some element types. For example, CBUSH is of "spring" configuration in the Nastran user profile and CONN3D2 is of "rod" configuration in the Abaqus user profile. It is possible to map a CBUSH to CONN3D2 even though their configurations are different. The element mapping scheme must be under the *ElemTypeConversion block in the ConfigurationFile.txt file. You need to provide both configuration and type information to specify the element mapping scheme as shown for the Abaqus to Nastran direction below:

HM configuration Abaqus type Nastran type
Mass MASS CONM2
ROTARYI CONM2
SPRING1 CELAS1, CELAS2, CBUSH
DASHPOT1 CDAMP1
CONN3D2 CBUSH
CONN2D2 CBUSH
rigid BEAM RBE2
LINK RBE2
PIN RBE2
TIE RBE2
KINCOUP RBE2
COUP_KIN RBE2
COUP_DIS RBE2
RB3D2 RBE2
R2D2 RBE2
RAX2 RBE2
RB2D2 RBE2
rbe3 DCOUP3D RBE3
COUP_DIS RBE3
DCOUP2D RBE3
rigidlink KINCOUP RBE2
RB3D2 RBE2
BEAM RBE2
LINK RBE2
PIN RBE2
TIE RBE2
COUP_KIN RBE2
COUP_DIS RBE2
R2D2 RBE2
RAX2 RBE2
spring SPRING2 CELAS1,CBUSH
SPRINGA CBUSH
DASHPOT2 CDAMP1, CBUSH
DASHPOTA CBUSH
JOINTC CBUSH
bar2 B31 CBAR,CBEAM
B31H CBAR,CBEAM
B33 CBAR,CBEAM
B33H CBAR,CBEAM
B31OS CBAR,CBEAM
B31OSH CBAR,CBEAM
PIPE31 CBAR,CBEAM
PIPE31H CBAR,CBEAM
ELBOW31 CBAR,CBEAM
ELBOW31B CBAR,CBEAM
ELBOW31C CBAR,CBEAM
AC1D2 CBAR,CBEAM
GK3D2 CBAR,CBEAM
GK3D2N CBAR,CBEAM
SAX1 CBAR,CBEAM
B21 CBAR,CBEAM
B21H CBAR,CBEAM
B23 CBAR,CBEAM
B23H CBAR,CBEAM
PIPE21 CBAR,CBEAM
PIPE21H CBAR,CBEAM
F2D2 CBAR,CBEAM
FAX2 CBAR,CBEAM
bar3 B32 CBAR,CBEAM
B32H CBAR,CBEAM
B32OS CBAR,CBEAM
B32OSH CBAR,CBEAM
PIPE32 CBAR,CBEAM
PIPE32H CBAR,CBEAM
ELBOW32 CBAR,CBEAM
AC1D3 CBAR,CBEAM
MGAX2 CBAR,CBEAM
SFMAX2 CBAR,CBEAM
SFMGAX2 CBAR,CBEAM
SAX2 CBAR,CBEAM
B22 CBAR,CBEAM
B22H CBAR,CBEAM
PIPE22 CBAR,CBEAM
PIPE22H CBAR,CBEAM
rod T3D2 CROD
T3D2H CROD
T3D2T CROD
T3D2E CROD
MGAX1 CROD
SFMAX1 CROD
SFMGAX1 CROD
CONN3D2 CBUSH
T2D2 CROD
T2D2H CROD
T2D2T CROD
T2D2E CROD
GK2D2 CROD
GK2D2N CROD
CONN2D2 spring CELAS1,CELAS2,CBUSH
gap GAPUNI CGAP
GAPCYL CGAP
GAPSPHER CGAP
tria3 S3 CTRIA3,CTRIAR
S3R CTRIA3,CTRIAR
STRI3 CTRIA3,CTRIAR
M3D3 CTRIA3,CTRIAR
SFM3D3 CTRIA3,CTRIAR
R3D3 CTRIA3,CTRIAR
DS3 CTRIA3,CTRIAR
CPE3 CTRIA3,CTRIAR
CPE3H CTRIA3,CTRIAR
CPE3E CTRIA3,CTRIAR
CPS3 CTRIA3,CTRIAR
CPS3E CTRIA3,CTRIAR
CAX3 CTRIA3,CTRIAR
CAX3H CTRIA3,CTRIAR
CAX3E CTRIA3,CTRIAR
CGAX3 CTRIA3,CTRIAR
CGAX3H CTRIA3,CTRIAR
AC2D3 CTRIA3,CTRIAR
ACAX3 CTRIA3,CTRIAR
DCAX3 CTRIA3,CTRIAR
DCAX3E CTRIA3,CTRIAR
DC2D3 CTRIA3,CTRIAR
DC2D3E CTRIA3,CTRIAR
quad4 S4 CQUAD4,CQUADR
S4R CQUAD4,CQUADR
S4R5 CQUAD4,CQUADR
M3D4 CQUAD4,CQUADR
M3D4R CQUAD4,CQUADR
SFM3D4 CQUAD4,CQUADR
SFM3D4R CQUAD4,CQUADR
R3D4 CQUAD4,CQUADR
DS4 CQUAD4,CQUADR
GK3D4L CQUAD4,CQUADR
GK3D4LN CQUAD4,CQUADR
F3D4 CQUAD4,CQUADR
CPE4I CQUAD4,CQUADR
CPE4 CQUAD4,CQUADR
CPE4H CQUAD4,CQUADR
CPE4IH CQUAD4,CQUADR
CPE4R CQUAD4,CQUADR
CPE4RH CQUAD4,CQUADR
CPE4T CQUAD4,CQUADR
CPE4HT CQUAD4,CQUADR
CPE4E CQUAD4,CQUADR
CPS4 CQUAD4,CQUADR
CPS4I CQUAD4,CQUADR
CPS4R CQUAD4,CQUADR
CPS4T CQUAD4,CQUADR
CPS4E CQUAD4,CQUADR
CAX4 CQUAD4,CQUADR
CAX4H CQUAD4,CQUADR
CAX4I CQUAD4,CQUADR
CAX4IH CQUAD4,CQUADR
CAX4R CQUAD4,CQUADR
CAX4RH CQUAD4,CQUADR
CAX4T CQUAD4,CQUADR
CAX4HT CQUAD4,CQUADR
CAX4E CQUAD4,CQUADR
CAXA4N CQUAD4,CQUADR
CAXA4HN CQUAD4,CQUADR
CAXA4RN CQUAD4,CQUADR
CAXA4RHN CQUAD4,CQUADR
CGAX4 CQUAD4,CQUADR
CGAX4H CQUAD4,CQUADR
CGAX4R CQUAD4,CQUADR
CGAX4RH CQUAD4,CQUADR
AC2D4 CQUAD4,CQUADR
ACAX4 CQUAD4,CQUADR
DC2D4 CQUAD4,CQUADR
DC2D4E CQUAD4,CQUADR
DCAX4 CQUAD4,CQUADR
DCAX4E CQUAD4,CQUADR
DCCAX4 CQUAD4,CQUADR
DCCAX4D CQUAD4,CQUADR
GKPS4 CQUAD4,CQUADR
GKPE4 CQUAD4,CQUADR
GKPS4N CQUAD4,CQUADR
tria6 STRI65 CTRIA6
M3D6 CTRIA6
SFM3D6 CTRIA6
DS6 CTRIA6
CPE6 CTRIA6
CPE6H CTRIA6
CPE6M CTRIA6
CPE6MH CTRIA6
CPS6 CTRIA6
CPS6M CTRIA6
AC2D6 CTRIA6
ACAX6 CTRIA6
DCAX6 CTRIA6
DC2D6 CTRIA6
DCAX6E CTRIA6
DC2D6E CTRIA6
CAX6 CTRIA6
CAX6H CTRIA6
CAX6M CTRIA6
CAX6MH CTRIA6
CGAX6 CTRIA6
CGAX6H CTRIA6
quad8 S8R CQUAD8
S8R5 CQUAD8
S8RT CQUAD8
M3D8 CQUAD8
M3D8R CQUAD8
SFM3D8 CQUAD8
SFM3D8R CQUAD8
DS8 CQUAD8
CPE8 CQUAD8
CPE8H CQUAD8
CPE8R CQUAD8
CPE8RH CQUAD8
CPS8 CQUAD8
CPS8R CQUAD8
AC2D8 CQUAD8
ACAX8 CQUAD8
DC2D8 CQUAD8
DCAX8 CQUAD8
DCAX8E CQUAD8
DC2D8E CQUAD8
CAX8 CQUAD8
CAX8H CQUAD8
CAX8HT CQUAD8
CAX8R CQUAD8
CAX8RH CQUAD8
CAX8RHT CQUAD8
CAX8RHT CQUAD8
CGAX8 CQUAD8
CGAX8H CQUAD8
CGAX8R CQUAD8
CGAX8RH CQUAD8
CAXA8N CQUAD8
CAXA8HN CQUAD8
CAXA8PN CQUAD8
CAXA8RN CQUAD8
CAXA8RHN CQUAD8
CAXA8RPN CQUAD8
tetra4 C3D4 CTETRA
C3D4H CTETRA
C3D4E CTETRA
AC3D4 CTETRA
DC3D4 CTETRA
DC3D4E CTETRA
penta6 C3D6 CPENTA
C3D6H CPENTA
C3D6E CPENTA
AC3D6 CPENTA
GK3D6 CPENTA
GK3D6N CPENTA
SC6R CPENTA
COH3D6 CPENTA
hex8 C3D8I
C3D8
C3D8T
C3D8H
C3D8HT
C3D8IH
C3D8R
C3D8RH
C3D8E
AC3D8
DC3D8
DC3D8E
DCC3D8
DCC3D8D
SC8R
COH3D8
tetra10 C3D10 DC3D10
C3D10H DC3D11
C3D10M DC3D12
C3D10MH DC3D13
C3D10E DC3D14
DC3D10E DC3D15
AC3D10 DC3D16
DC3D10 DC3D17
penta15 C3D15 CPENTA
C3D15H CPENTA
C3D15E CPENTA
AC3D15 CPENTA
DC3D15 CPENTA
DC3D15E CPENTA
hex20 C3D20 CHEXA
C3D20H CHEXA
C3D20R CHEXA
C3D20RH CHEXA
C3D20E CHEXA
C3D20RE CHEXA
C3D20T CHEXA
C3D20HT CHEXA
C3D20RT CHEXA
C3D20RHT CHEXA
DC3D20 CHEXA
AC3D20 CHEXA
DC3D20E CHEXA
Abaqus CONN3D2 connector elements are converted to Nastran CBUSH, PBUSH using the following guidelines:
  • Connector1 types converted:
    • AXIAL: Active = [1], Rigid = [-]
    • CARTESIAN, PROJECTION CARTESIAN: Active = [123], Rigid = [-]
    • JOIN: Active = [-], Rigid = [123]
    • RADIAL-THRUST: Active = [13]*, Rigid = [-]
      Note: Requires cylindrical system
    • SLIDE-PLANE: Active = [23], Rigid = [1]
    • SLOT: Active = [1], Rigid = [23]
  • Connector2 types converted:
    • ALIGN: Active = [-], Rigid = [456]
    • CARDAN, EULER, ROTATION, FLEXION-TORSION, PROJECTION FLEXION-TORSION: Active = [456], Rigid = [-]
    • REVOLUTE: Active = [4], Rigid = [56]
  • Special assembled Connector1 types:
    • BEAM, WELD = (JOIN + ALIGN): Active = [-], Rigid = [123456]
    • CYLINDRICAL = (SLOT + REVOLUTE): Active = [14], Rigid = [2356]
    • HINGE = (JOIN + REVOLUTE): Active = [4], Rigid = [12356]
    • PLANAR = (SLIDE-PLANE + REVOLUTE): Active = [234], Rigid = [156]
    • TRANSLATOR = (SLOT + ALIGN): Active = [1], Rigid = [23456]
    • BUSHING = (PROJECTION CARTESIAN + PROJECTION FLEXION-TORSION): Active = [123456], Rigid = [-]
  • PBUSH stiffness and damping values (Ki, Bi) for active DOFs are mapped from *CONNECTOR BEHAVIOR material data. Rigid DOFs map to RIGID option inside PBUSH.
  • CBUSH orientation is mapped from *CONNECTOR SECTION Orientation system.
    • Only 1 Orientation system can be mapped to CBUSH CID.
    • If 2 Orientation systems are present in the Abaqus card, only the first one is mapped.

It is also possible to use a simplified conversion of Abaqus connectors (CONN3D2) to rbe2 elements when modifying the ConfigurationFile.txt file. Change the entry for rod element type configuration to: rod,CONN3D2 rigid,rbe2

CONN3D2 elements will now be converted to RBE2 elements. Depending on the connection type set in the CONNECTOR SECTION, such as AXIAL or HINGE, degrees of freedom will be set for the RBE2 element. If systems are associated to the connector elemental nodes they will be assigned to the nodes of the RBE2 as well. Not all connection types are supported. If a system is ignored by a particular CONNECTOR SECTION, it will not be assigned to the nodes of the RBE2 either.

These connector types are currently considered in conversion: AXIAL, JOIN, LINK, SLIDE-PLANE, SLOT, ALIGN, REVOLUTE, BEAM, CYLINDRICAL, HINGE, PLANAR, TRANSLATOR, WELD.

*COUPLING/*KINEMATIC constraints with element based surfaces, currently mapped to groups in the application, are converted into RBE2 rigid elements. *COUPLING/*DISTRIBUTING constraints are converted to RBE3 elements.

All SPRING and DASHPOT related conversions (including JOINTC) map to CELAS1, CDAMP1, or CBUSH/PBUSH using the following guidelines:
  • SPRING1/2 without ORIENTATION converts to CELAS1
  • SPRINGA or SPRING1/2 with ORIENTATION converts to CBUSH/PBUSH/PBUSHT with K/KN lines. For SPRING1/2, ORIENTATION maps to CBUSH, CID.
  • DASHPOT1/2 without ORIENTATION converts to CDAMP1
  • DASHPOTA or DASHPOT1/2 with ORIENTATION converts to CBUSH/PBUSH/PBUSHT with B line. For DASHPOT1/2, ORIENTATION maps to CBUSH, CID.

Sectional Properties

Some of the properties in one solver can be converted to two different sections in the other solver. For an Abaqus to Nastran conversion, for example, *DASHPOT can be converted to *PELAS or PDAMP. The property mapping scheme can be edited under the *PropertyConversion block in the ConfigurationFile.txt file.

Note: The property conversion scheme and corresponding element conversion scheme must be consistent. For example, if you define *CONNECTOR SECTION to PBUSH at the property mapping scheme, the corresponding element CONN3D2 must map to CBUSH in the element mapping scheme.

For SOLID SECTION the converter will always convert to PSOLID unless the property has a data line indicating a cross-sectional area for a truss element. In this case, conversion results in a PROD property.

For BEAM (GENERAL) SECTION the algorithm automatically decides which property to convert to depending on the element type chosen in the ElementTypeConversion section of the ConfigurationFile.txt. For example, if you want to convert B31 elements to CBAR, the beam property will get converted to a PBAR or PBARL property. If you choose to convert B31 elements to CBEAM, then the converter creates PBEAM or PBEAML properties accordingly. The same logic applies to B32 elements; the difference is that they are changed to first order beam elements first on conversion.
Abaqus type Nastran type
*BEAM GENERAL SECTION PBAR(L), PBEAM(L)
*BEAM SECTION PBAR(L), PBEAM(L)
*CONNECTOR SECTION PELAS,PBUSH
*DASHPOT PELAS,PDAMP
*GAP PGAP
*MASS CONM2
*MEMBRANE SECTION PSHELL
*ROTARY INERTIA CONM2
*SHELL GENERAL SECTION PSHELL
*SHELL SECTION PSHELL
*SOLID SECTION PSOLID
*SPRING PELAS, PBUSH
*SOLID SECTION (Homogeneous) PROD
*SHELL GENERAL SECTION (Homogeneous) PSHELL
*SHELL SECTION (Homogeneous) PSHELL
*SHELL GENERAL SECTION (User) PSHELL
*SHELL SECTION (Composite) PCOMP, PCOMPG
*SHELL GENERAL SECTION (Composite) PCOMP, PCOMPG

Materials

The material mapping scheme can be edited under *PropertyConversion block in the ConfigurationFile.txt file.
Abaqus Nastran type
*MATERIAL MAT1, MAT4, MATT1, MATS1
*CONNECTOR BEHAVIOR PBUSH, PELAS

Loads

Loads have two basic attributes – configuration (or config) and type. The supported load "configs" are: force, moment, constraint, pressure, temperature, flux, velocity, acceleration and equation. The load "type" defines the solver specific type of a particular configuration. For example, pressure load can be any of the following Nastran types: PLOAD, PLOAD2 or PLOAD4. The Load Types panel shows all supported load configurations and their types for a user profile.

The converter also converts distributed surfaces loads (*DLSOAD) applied on faces of shell or solid elements into pressure loads (PLOAD4).

For a specific configuration, you can map any supported Abaqus load type to any supported Nastran load type. The conversion tool does not support conversion across load configurations. The load mapping scheme can be edited under the *BCsTypeConversion block in the ConfigurationFile.txt file. You need to provide both configuration and type information to specify the mapping scheme as shown below:
HM configuration Abaqus type Nastran type
temperature TEMPERATURE TEMP
pressure DLOAD PLOAD,PLOAD2,PLOAD4
Constraint ACCELERATION SPCD
VELOCITY SPCD
BOUNDARY SPC,SUPORT
moment CLOAD MOMENT
force CLOAD FORCE
equation EQUATION MPC

Sets

Abaqus type Nastran type
*NSET SET
*ELSET SET

Systems

Abaqus type Nastran type
*ORIENTATION CORD2C,CORD2R,CORD2S
*SYSTEM CORD2C,CORD2R,CORD2S
*TRANSFORM CORD2C,CORD2R,CORD2S
*TRANSFORM- USER DEFINED NSET CORD2C,CORD2R,CORD2S

Load Steps and Analysis Type

The conversion tool maps between Abaqus steps and Nastran subcases. It does not convert Abaqus analysis type to the solution type. You must define it manually using the Load Step Browser.

The converter converts *STEP into SUBCASE. Load collector references are maintained upon conversion. If multiple load collectors of a particular step contain constraints, a SPCADD card is created automatically. The same happens in case of loads in separate load collectors; a new LOAD card is created on conversion.