Page 159 - Using ANSYS for Finite Element Analysis Dynamic, Probabilistic, Design and Heat Transfer Analysis

146 • using ansys for finite eLement anaLysis
Both methods have advantages and disadvantages. Creating the file
with a system editor is the same as creating a batch input file for the analy-
sis. This method allows you full control of parametric definitions through
exact command inputs. It also eliminates the need to clean out unneces-
sary commands later. However, if you are not moderately familiar with
ANSYS commands, this method may be inconvenient. You may find it
easier to perform the initial analysis interactively, and then use the result-
ing command log as the basis for the analysis file. In this case, final editing
of the log file may be required in order to make it suitable for optimization
looping.

4.1.1 AnALySiS FiLe USing Log FiLeS

The ANSYS program records every command it executes, whether typed
in directly or executed by a function in the GUI, in two places: the
session log file and the internal database command log.

• The session log file is a text file that is saved in your working
directory.
• The database command log is saved in the ANSYS database. You
can copy this log to a file at any time by choosing Utility Menu>
File> Write DB Log File.

Both files are command logs that can be used as input to the ANSYS
program.

4.1.1.1 Session Log File

Every ANSYS session produces a session log named Jobname.LOG. The
default jobname is FILE or file, depending on the operating system. The
program opens the log file when you first enter the program, and closes
it when you exit the program. The session log file provides a complete
record of your ANSYS session (in terms of commands) and is quite valu-
able as a means of recovering from a system crash or catastrophic user
mistake. By reading in a renamed copy of your log file (or by submitting
it as a batch file), you can re-execute every command in your log file, rec-
reating your database exactly as it existed previously.
Your log file is also useful as a debugging tool that can help to reveal
any mistakes you might have made in an ANSYS session. Should you