Engine Log File

Each time a EX3 analysis is computed, a LOG file (*.log) is created which summarizes a few key analysis parameters from the finite element analysis (e.g. number of iterations, convergence history etc). This file can be viewed by selecting View Engine Log File from the Analysis menu.

This will display the LOG file in its own view. The LOG file information can then be copied to the clipboard, saved to a file, etc. if desired.

Warning Message When Loading File

A warning message is displayed in the program when a file is opened, and the number of iterations has reached the maximum number allowable. This occurs when the prescribed tolerance in the iteration process of the plasticity analysis was not achieved, during the EX3 analysis. This means that the program did not find the equilibrium state for the model. The Convergence history for an EX3 analysis is recorded in the LOG file.

The Maximum Number of Iterations and the Tolerance required for convergence are specified in the Project Settings dialog.

If this warning message appears, this can be the result of a number of things, including:

1. The model has no equilibrium state. Basically, you get a collapse and continued deformation. A stable model will generally require some type of support. In some cases, this can be caused by underestimating the strength of the rock mass or overestimating the initial stresses, either of which can lead to this behaviour.
2. The number of iterations is too low. The default number of iterations is 500, this can be increased in the Project Settings dialog. In models where a lot of failure and plasticity are occurring, a higher number of iterations might be required. A way to determine if this is the case is to watch the tolerance as the Compute engine is running. If the tolerance is getting smaller as the maximum number of iterations is approached, then you may want to increase the number of iterations. If the tolerance is bouncing all over the place with no obvious reduction, then the most likely reason is that the model does not have an equilibrium state (see #1, above).

Even when the maximum number of iterations has been reached, the results can still be meaningful if you realize that they are not the equilibrium values. They do give you the trend of the stresses, failure and displacements.