If the last line of the Summary file is 'Generate Elements Automatically' and nothing else happens for a very long time, you may also have a problem, or you may not. The key to this is what defines 'a very long time'. If you have run the model or similar models before, you may use that as a basis for comparison. If you start the model and run it over night without it getting past the 'Generating Elements Automatically' message, that would be a very long time. Small simple models should not take more than a few minutes. Larger more complex models may take as long as an hour or more.
If after watching the Summary file for a few minutes, if you think it is taking too long, or you see an error message, the next place to check is the Log file (*.pas file in the study folder). You may do this by selecting the Log button on the Run Data Form after you have started the job. The log file will show many more messages about the progress of the meshing process. Read the messages.
The Log file will give you messages about geometry problems, meshing problems and the status every 30 seconds on how many elements have been created. The status will also show what percent of the mesh is complete.
If you see errors or warning messages during this phase along with an excessive amount of time being used to generate elements, this is an indication of a problem. Errors and warning messages are generally not a good thing, but, sometimes Pro/MECHANICA will fix the problems and complete the mesh anyway. If things seem to be moving forward it is best to give it some time to see if it will finish or stop with a fatal error. If the model meshing seems to be hung, then you should stop the process from the Run menu.
After the mesh process has stopped you may use the 'Diagnose' button to help debug the model. This button will step through all of the error messages in the Log file and highlight the geometry where the problem occurred. Sometimes this will give you a clue as to where to look for trouble.
Sometimes, given enough time, the meshing will complete with no errors but with an excessive number of elements. The more elements created, the longer the mesh time and the longer the solution time as well. This is usually because of some features in the model that the meshing is having a problem with. How many elements represent an excessive number? The general rule is that your model should be as simple as possible while still of high enough fidelity to provide the required information following the solution. In other words, leave off features or detail that are not important to the solution as long as they do not diminish the accuracy of the overall result. With today's compute power, and depending on what type of simulation you are running, a large model may be over 20000 elements. A medium size model will be less than 10000 elements.
<TSD Engineering HOME>
Copyright 2003, TSD Engineering