Mechanical APDL Basic Analysis Guide - Ansys

Chapter 7:The General Postprocessor (POST1)
• You, not the program, assign the load step and substep numbers used to identify the data.
• Only summable and constant data are available by default; non-summable data are not written to the
results file unless requested (LCSUM command).
The following example illustrates use of the RAPPND command:
/POST1 ! Following a 2 load step analysis
SET,1 ! Store load step 1
LCDEF,1,2 ! Identify load step 2 as load case 1
LCOPER,ADD,1 ! Add load case 1 to database (ls 1 + ls 2)
RAPPND,3,3 ! Append the combined results to the results file
! as ls 3, time = 3
SET,LIST ! Observe addition of new load step to results file
You can use the RAPPND command to combine results from two results files (created with the same database.)
You can use the POST1 FILE command (Main Menu> General Postproc> Data & File Opts) to "toggle"
between the two results files to alternately store results from one and append to the other.
Notes
• You can define a load case by setting a pointer to a load case file with the LCFILE command (Main
Menu> General Postproc> Load Case> Create Load Case). Then, you can use the LCASE or LCOPER
commands to read data from the file into memory.
• You can erase any load case by issuing LCDEF,LCNO,ERASE, where LCNO is the load case number. To
erase all load cases, issue LCDEF,ERASE. These options not only delete all load case pointers, but also
delete the appropriate load case files (those with the default file name extensions).
• To zero the results portion of the database, issue LCZERO (Main Menu> General Postproc> Load
Case> Zero Load Case) or LCOPER,ZERO.
• The LCABS and LCFACT commands (Main Menu> General Postproc> Load Case> Calc Options>
Absolut Value and Main Menu> General Postproc> Load Case> Calc Options> Scale Factor), allow
you to specify absolute values and scale factors for specific load cases. The program uses these specifications
when you issue either LCASE or LCOPER. ANSYS applies scale factors after it calculates absolute
values.
• Results data read into the database from the results file (via SET or LCASE commands) will include
boundary condition information (constraints and force loads). However, load cases read in from a load
case file will not. Therefore, if boundary conditions appear on graphics displays after you issue an LCASE
command (Main Menu> General Postproc> Load Case> Read Load Case), they are from a previously
processed load case. The LCASE command does not reset the boundary condition information in
memory.
• After a load case combination is performed for structural line elements, the principal stress data are not
automatically updated in the database. Issue LCOPER,LPRIN to recalculate line element principal stresses
based on the current component stress values.
• You can select a subset of load cases using the LCSEL command (Main Menu> General Postproc>
Load Case> Calc Options> Sele Ld Cases). Once a subset is selected, you can use the label ALL in
place of a load case number on load case operations.
• You cannot use load case combinations with FLOTRAN results data.
• Element nodal forces are operated on before summing at the node.
7.4.3.2. Combining Load Cases in Harmonic Element Models
For models with harmonic elements (axisymmetric elements with nonaxisymmetric loads), the loads are
frequently applied in a series of load steps based on a Fourier decomposition (See the Element Reference).
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