Think of a set as a list or bucket of numbers.

We use various methods to programmatically isolate ID’s and then put them into the sets for later processing. In this case, it will be added to a group that we’re trying to create. Next, we’ll declare and initialize a group.

Dim newGroup As femap.Group

Set newGroup = App.feGroup

Note that this doesn’t yet create a Femap group, this is just a group object.

elemSet.AddRule(FTO_TRIA3,FGD_ELEM_BYSHAPE)

We’ll use the add rule method of the elem set/set object and narrow down selected model elements to only those of a certain shape. That’s why we’re using the FGD by shape argument for the add rule method.

The FTO_TRIA3 argument of the add rule method is used since we’re looking for three-noded triangles.

Using these two particular inputs in this way adds all triangle element IDs to the elem set/set object.

Next, we’ll create a variable to store an ID for the group we’ve created.

Dim new GroupID As Long

newGroupID = newGroup.NextEmptyID

The next empty ID method, of the group object, returns the next available Group ID in the model. We don’t have any existing groups, so right now it will just be Group 1, but if we already had a Group 1, it would automatically be placed into Group 2. This will be important when we save the new group to the model.

Add the set IDs to the group that we found before:

newGroup.SetAdd(FT_ELEM,elem.Set.ID)

Note that the IDs are associated with elements because it was a list that we had before in our set.

Lastly, we will create a title for the new group and then place the group in the database.

newGroup.title = "Triangle elements"

newGroup.Put(newGroupID)

Put will save the new group to the database using the ID found as the next empty ID.

Done.

Here’s what the final code looks like:

Sub Main
Dim App As femap.model
Set App = feFemap()

Dim elemSet As femap.Set
Set elemSet = App.feSet

Dim newGroup As femap.Group
Set newGroup = App.feGroup

elemSet.AddRule(FTO_TRIA3,FGD_ELEM_BYSHAPE)

Dim newGroupID As Long
newGroupID = newGroup.NextEmptyID

newGroup.SetAdd(FT_ELEM,elemSet.ID)

newGroup.title = "Triangle elements"
newGroup.Put(newGroupID)

End Sub

Click the play button:

      

      

RECAP: In a short amount of time, we were able to create a useful model check using a handful of methods belonging to three distinct objects: the Femap application object, the element set, and the group.

Programming in Excel (3rd Party Interfaces)

      

In the last demonstration, we got Femap to interact with itself, being that we were programming within its own application.

But now we’re going to drive Femap from Excel (using the COM / OLE interface in Windows).

All you need to know is that very little is different between programming in the two programs since they’re based on a similar coding language.

A couple of tricks to get started in Excel:

1. Create Marco Enabled Worksheet
2. Add the Developer Tab
3. Add reference to the Femap type library file which can be found in the installation directory of Femap.
   

Create a new Marco:

      

Name the Macro “modifylayer” and press Create.

      

That will bring up the coding window and we can start coding for the operation.

We’re going to connect to Femap by using:

Dim app As femap.Model

Set app = GetObject (, "femap.model")

This line connects our worksheet to the current Femap session.

Next we’re going to set a variable for a return code:

Dim rc As Integer

A return code is used by the Femap API as a status, delivered after calling methods, that indicates whether an operation failed or succeeded. Methods can’t be called without capturing the return code in Excel.

(It can in Femap which is why we didn’t use that line in the first example)

Create a set to add the list of elements that are going to be moved to a different layer.

Dim elemSet As femap.Set

Set elemSet = app.feSet

Next call the add range method:

rc = elemSet.AddRange (ActiveSheet.Cells(6, 1).Value, ActiveSheet.Cells(6, 2).Value, 1)

The add range method of the element set object is the unique aspect of Excel where you specify the lower bound, upper bound, and increment using the cells in the Excel file.

Notice that we link cell (6,1) which is cell A6 and the range end in cell B6.

This will move elements with IDs between 400-500 onto a new layer.

Next, call the modify layer method of the Femap application object to enact that change:

rc = app.feModifyLayer (FT_ELEM, elemSet.ID, 2)

This takes in the type of entity being moved, which here is set as FT_ELEM.

FT_ELEM is a Femap constant that can be found in the API reference manual (we’ll discuss the reference manual later). It specifies the entity type and then we specify the set ID of the element being moved, which we previously referenced to the range of 400-500. It also takes in, as one of the arguments, the destination layer ID.

Our finalized code:

Sub modifylayer()

Dim app As femap.Model
Set app = GetObject(, "femap.model")

Dim rc As Integer

Dim elemSet As femap.Set
Set elemSet = app.feSet

rc = elemSet.AddRange(ActiveSheet.Cells(6, 1). Value, ActiveSheet.Cells(6,
2).Value, 1)

rc = app.feModifyLayer(FT_ELEM,
elemSet.ID, 2)

End Sub

If we go back to Femap and create a new layer.

      

  

    

RECAP: We made a change to Femap using an external application; in this case Microsoft Excel.

Using the API to Automate Repetitive Tasks

Now that we have an idea of how to use the Femap API, let’s look at an example of how it can save you time.

In this demonstration, we’ll create a script that generates and assigns new properties to elements for all the selected groups in an orthogrid drop test model.

      

The goal of this script is to turn each of the orthogrid webs into unique property zones.

Why?

One use of breaking up models in this manner is to allow optimization software to equally size each property to get as much mass out of the model as possible.

First we will create groups by going to Group > Operations > Generate.

      

Select Methods > Property.

   

      

Press Select All, and then check the Remove button and select the following node to unselect the outer ring.

      

     

Hit OK.

Select None under Attribute Breaks and NonManifold Edges under Geometric Breaks. This option creates a break so that each web segment is put in its own group.

      

Press OK and now we have 189 groups that all correspond to new segments.

      

Now we will use the API to generate and assign new properties to the elements in all 189 groups in one click!

We have this API already built and saved to our custom tools. On the toolbar, under Custom Tools, we’ll select the AutoAssignProperties API.

     

A prompt shows up asking us for which groups to select. Select All to select all the groups we’ve created.

      

A second prompt will ask for a starting ID, which we will set at 100. Press OK.

      

Done.

Just like that, the script has generated and assigned new properties to all the individual webs.

To better visualize the effects, right click Properties, go to Color, and Press Random > OK.

      

Without using any Property Creation menus, we have now created 189 new properties.

The programs for each component type included specific steps that automatically created appropriate finite element meshes, midsurfaces and nodal masses based on the geometry. The programs also accessed component technical data from Excel when needed. For postprocessing tasks, Cardinal engineers developed additional programs that determine maximum stresses from analysis output sets; perform plate pull-through and tear-out stress calculations; and calculate bolt stresses. For those calculations, the programs also output the resulting data to Excel spreadsheets. In the video below, John Hering from Cardinal Engineering details his company’s use of API’s in the analysis of ship piping for a customer.

Femap API Reference Manual

The API Reference Manual by the Femap Team can be found in the \PDF folder in the Femap install directory. This is a comprehensive 2000+ page document that goes into great detail on all aspects of Femap API programming and is likely to have answers to any questions you might have.