Simplifying the Geometry...

Often times Pro/ENGINEER models have much more detail than is needed. The objective in creating an FEA model is to have the simplest model possible and only include the features required to adequately define the problem. Many times features may be left out of the model that will have little of no impact on the result. Sometimes features that do impact the result may be left out if they provide a conservative solution. The goal is to end up with a model that is simple and has very few elements.

The most important features to focus on are the ones the cause the mesher to go crazy.

You need to ask what features are needed and what impact will they have on the result if they are left out. Strip the model to its bare bones. Sometimes this is an iterative process. If you have a model that you know you are going to run many times or you want to optimize, you may run several iterations of de-featuring to see how simple you can get it.

Thin features, sliver surfaces and small corner angle surfaces are the ones that cause Pro/MECHANICA the most problems. The size of the elements in, around and on these features is limited by the element settings. The most limiting setting is the minimum/maximum corner angle of 5 to 175 degrees. This will generally dictate the minimum number of elements that will be created.

There are several standard methods to simplify geometry that most Pro/ENGINEER users are familiar with such as Simplified Reps and Feature Suppression, but there are also a couple of methods that most design engineers would never think of, such as adding Cut or Protrusion features to get rid of unwanted geometry. The following example shows how this may work.

> Simplified Rep
> Feature Suppression
> Cuts and Protrusions
> Modify the Dimensions

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