Importing Load Sets

Load sets are imported from the case control section. Each subcase ID will become a HyperSizer load set with the same ID.

The determination of whether a load set is mechanical or thermal depends on the contents of the Nastran subcase. By default all subcases imported as mechanical load sets. If the TEMP command is found in a subcase, the load set is defined as thermal.

The following case control section contains four subcases and imports to HyperSizer as four load sets, three mechanical and one thermal.

INIT MASTER(S) $ Required so that Nastran deletes temporary files after each run.

SOL SESTATICS

CEND

  TITLE = Wing box

  ECHO = NONE

  FORCE(PRINT) = ALL $ F06 Output Requested

  DISPLACEMENT(PRINT) = ALL

SUBCASE 101

  SUBTITLE = Wing Pressure

  SPC  = 100

  LOAD = 101

SUBCASE 102

  SUBTITLE = Fuselage Pressure

  SPC  = 100

  LOAD = 102

SUBCASE 103

  SUBTITLE = Fuselage Bending

  SPC  = 100

  LOAD = 103

SUBCASE 201

  SUBTITLE = Wing Temperature

  SPC  = 100

  TEMP(LOAD) = 201

Load sets in HyperSizer are equivalent to Abaqus steps. Any step with element temperatures defined with the TEMPERATURE option is designated as a thermal load set; all other steps are mechanical.

Load set numbers are derived from the step names. An attempt is made to extract a number from the end of the step name string. If a number is not found, the load sets are numbered sequentially.

Important: Starting in Version 6.3, all step names must end in a unique integer ID. *Step, name=Landing_101 is acceptable. *Step, name=Landing will not import.

** Mechanical Load Set 101

*Step, Name=Wing_Pressure_101

…

*El File, Directions=Yes, Position=Centroidal

SF

*El File

LOADS

*Node File

U

*End Step

** Thermal Load Set 201

*Step, Name=Wing_Temperature_201

*Temperature

…

*El File, Position=Centroidal

SF

*El File

TEMP

*Node File

U

*End Step

*STATIC, *DYNAMIC, or *BUCKLE options for linear or non-linear analysis are supported. For each step, HyperSizer will pull loads from the FEA results corresponding to the last increment in each step. The last increment always corresponds to the time period of the step.

Important: A load step is not imported unless it is associated with a SOLVE or LSSOLVE command.

A load set is equivalent to a ANSYS load step. A load step is not imported unless it is associated with a SOLVE or LSSOLVE command.

Both the input file (*.CDB or *.INP) and the load step files (*.S#) are parsed for load set data. Load set numbers are taken from the LSWRITE, LSREAD, and LSSOLVE commands. Any load step containing thermal loads in the form of BF, BFE, or TUNIF commands is considered a thermal load set. TREF defines the mechanical reference temperature, and \TITLE is used for the load step description.

The first three examples will import load sets 101, 102, and 103 using different combinations of ANSYS commands.

Example: LSSOLVE

/SOLU

LSSOLVE,101,103 ! 101 through 103

FINISH

Example: LSREAD + SOLVE

/SOLU

!

LSREAD,101

SOLVE

LSCLEAR,ALL

!

LSREAD,102

SOLVE

LSCLEAR,ALL

!

LSREAD,103

SOLVE

LSCLEAR,ALL

!

FINISH

Example: LSWRITE + LSSOLVE

/SOLU

!

/TITLE, M1 Bending

TREF,95.0

D, 1,UX , 0.00000000 , 0.00000000

D, 1,UY , 0.00000000 , 0.00000000

D, 1,UZ , 0.00000000 , 0.00000000

D, 1,ROTX, 0.00000000 , 0.00000000

D, 1,ROTY, 0.00000000 , 0.00000000

D, 2,UX , 0.00000000 , 0.00000000

D, 2,UY , 0.00000000 , 0.00000000

D, 2,UZ , 0.00000000 , 0.00000000

D, 2,ROTX, 0.00000000 , 0.00000000

D, 2,ROTY, 0.00000000 , 0.00000000

F, 3,FY , -10000.0000 , 0.00000000

F, 4,FY , -10000.0000 , 0.00000000

LSWRITE,101

LSCLEAR,ALL

!

/TITLE, M2 Bending

TREF,60.0

TUNIF,200.0

D, 1,UX , 0.00000000 , 0.00000000

D, 1,UY , 0.00000000 , 0.00000000

D, 1,UZ , 0.00000000 , 0.00000000

D, 1,ROTX, 0.00000000 , 0.00000000

D, 1,ROTZ, 0.00000000 , 0.00000000

D, 2,UX , 0.00000000 , 0.00000000

D, 2,UY , 0.00000000 , 0.00000000

D, 2,UZ , 0.00000000 , 0.00000000

D, 2,ROTX, 0.00000000 , 0.00000000

D, 2,ROTZ, 0.00000000 , 0.00000000

F, 3,FZ , -10000.0000 , 0.00000000

F, 4,FZ , -10000.0000 , 0.00000000

LSWRITE,102

LSCLEAR,ALL

!

/TITLE, Twist

D, 1,UX , 0.00000000 , 0.00000000

D, 1,UY , 0.00000000 , 0.00000000

D, 1,UZ , 0.00000000 , 0.00000000

D, 1,ROTX, 0.00000000 , 0.00000000

D, 1,ROTY, 0.00000000 , 0.00000000

D, 1,ROTZ, 0.00000000 , 0.00000000

F, 2,MX , 15000.0000 , 0.00000000

LSWRITE,103

LSSOLVE,101,103

FINISH

Example: SOLVE

If just a single SOLVE command is present, a single load set will be imported.

/SOLU

!

SOLVE

!

FINISH