Chapter 8: The Time-History Postprocessor (POST26)

Use the POST26 time-history postprocessor (/POST26) to review analysis results at specific locations in the model as a function of time, frequency, or some other change in the analysis parameters that can be related to time. In this mode, you can process results data in many ways. You can construct graphics displays, chart representations or tabular listings, or you can perform math operations on your data sets. A typical time-history task would be to graph result items versus time in a transient analysis, or to graph force versus deflection in a nonlinear structural analysis.

After you have solved an analysis, the program uses the results data to create a results file. The active results file (*.rst, *.rth, *.rmg, etc.) is loaded automatically when postprocessing is initiated.

You must have your geometry loaded and a valid results file must be available. If the current analysis contains no results file, you are prompted to provide one.

By default, the time-history processor looks for one of the standard results files described in The General Postprocessor (POST1); however, you can specify a different file (FILE).

Data sets and variable definitions created in the time-history postprocessor are maintained during the current session.

Following is the general process for using the time-history postprocessor:

  1. Enter the time-history processor (/POST26).

  2. Define time-history variables. This involves not only identifying the variables, but also storing the variables.

  3. Process the variables to develop calculated data or to extract or generate related variable sets.

  4. Prepare output (via graph plots, tabular listings, or file output).