All loads and load step options put together form a load step, for which the program can calculate the solution. If you have multiple load steps, you can store the data for each load step on a file, called the load step file, and read it in later for solution.
The LSWRITE command writes the load step file (one file per load step, identified as Jobname.S01, Jobname.S02, Jobname.S03, etc.).
After all load step files are written, you can issue one action command to read in the files sequentially and obtain the solution for each load step.
Example 3.10: Defining Multiple Load Steps
This set of commands defines multiple load steps:
/SOLU ! Enter SOLUTION 0 ! Load Step 1: D, ... ! Loads SF, ... ... NSUBST, ... ! Load step options KBC, ... OUTRES, ... OUTPR, ... ... LSWRITE ! Writes load step file: Jobname.S01
! Load Step 2: D, ... ! Loads SF, ... ... NSUBST, ... ! Load step options KBC, ... OUTRES, ... OUTPR, ... ... LSWRITE ! Writes load step file: Jobname.S02 0
The load step data are written to the file in terms of commands.
The LSWRITE command does not capture changes to real constants (R), material properties (MP), couplings (CP), or constraint equations (CE).
The LSWRITE command automatically transfers solid-model loads to the finite element model, so all loads are written in the form of finite-element load commands. In particular, surface loads are always written in terms of SFE (or SFBEAM) commands, regardless of how they were applied.
To modify data on load step file number n, issue the command LSREAD,n to read in the file, make the desired changes, and then issue LSWRITE,n (which overwrite the old file n). You can also directly edit the load step file using your system editor, but this is generally not recommended.
The LSDELE command enables you to delete load step files from within the program.
Another useful load-step-related command is LSCLEAR, which enables you to delete all loads and reset all load step options to their defaults. For example, you can use it to clean up the load step data before reading in a load step file for modifications.