Get mesh information of crack propagation with ACT Python

Hi,

I deal with crack propagation in Ansys. For testing, I use a simple example (half elliptical surface crack in cylinder under longitudinal load):

The simulation has 40 substeps (the mesh of the model is therefore changed 40 times by extending the crack). Now I want to get the crack front coordinates of each substep. To get the mesh object (and to check the number of nodes and element) in each substep I use this code:

reader = Model.Analyses[0].GetResultsData()
for index in range(1, reader.ResultSetCount + 1):
    reader.CurrentResultSet = index
    substep_mesh = reader.CreateMeshData()
    total_num_N = substep_mesh.NodeCount
    total_num_E = substep_mesh.ElementCount
    print index, total_num_N, total_num_E, front_num_N

The number of elements and nodes logically increases with each crack propagation. Now I want to get the NodeIDs in the Named Selection "NS_SECrack_Front", which is automatically created by Ansys and presumably contains different node numbers in each substep. I'll probably get the list by doing something like this:

front_set = substep_mesh.MeshRegionById(front_set_Id)
front_num_N = front_set.NodeCount

But how do I get the ID of the Named Selection? I have tried that, but it seems not work:

ns = {n.Name:n for n in model.NamedSelections.Children}
front_selection = ns['NS_SECrack_Front']
front_set_Id = front_selection.Id

It seems the ID of the Named Selection of the Model Data is not the same as in the Mesh Data of the substeps.

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Comments

ThomasDD

I simplify my question: How I get access to the Named Selections with ACT Python, if every substep in the result file has its own mesh?

Mike.Thompson

I am not sure if there is yet a pure python way to get this information. You may be best to use APDL and write this information to a text file, that you can later read from python to get the information. You can loop through the results sets with a *DO loop in APDL and then select the component at each set. Get the nodes in the component, and write these IDs to a text file.

You can also use *GET to get information about a crack front/tip if you need to ensure you get the nodes in specific crack order. You can get node 1, 2, 3 etc... in relation to the crack front, even if the global ids are arbitrary like 2345,435656,2343,etc....