Volume and mass of elements above a result threshold

Pernelle Marone-Hitz

Using ACT scripting, how can I find the elements for which the average stress is above a specific value and sum the volume of these elements, and find the summed mass of these elements ?

Pernelle Marone-Hitz

The following code can be adapted. Please note that this simplified example considers that only one material is used in the model.

# Define threshold
threshold = Quantity('100 [MPa]')

# init
summed_volume = 0
summed_mass = 0

# Insert result
eqv_stress = ExtAPI.DataModel.Project.Model.Analyses[0].Solution.AddEquivalentStress()
eqv_stress.DisplayOption = ResultAveragingType.ElementalMean
eqv_stress.EvaluateAllResults()

# Extract data from plot
plot_data = eqv_stress.PlotData
elements = plot_data ['Element']
result_value = plot_data ['Values']

# Mesh data
mesh_data = ExtAPI.DataModel.Project.Model.Analyses[0].MeshData

# Handle unit conversion
import units
result_unit = result_value.Unit
mesh_unit = mesh_data.Unit
scale_factor_stress = units.ConvertUnit(1.,result_unit,threshold.Unit)


for index in range(len(elements)):
  if result_value[index]*scale_factor_stress > threshold.Value:
    summed_volume = summed_volume + mesh_data.ElementById(elements[index]).Volume

summed_volume = Quantity(str(summed_volume) + '[' + mesh_unit + '^3]')
print('Summed volume is: ' + str(summed_volume))

# Get material 
# WARNING this code demo only grabs the material of the first body in the tree and assumes all elements above use this material
import materials
mat = ExtAPI.DataModel.Project.Model.Materials.Children[0]
# get engineering data material properties for this material
matED = mat.GetEngineeringDataMaterial()
density = materials.GetMaterialPropertyByName(matED,"Density")['Density']

# Get mass
summed_mass = summed_volume.Value*density[1]
print('Summed mass is: ' +str(summed_mass) + ' [kg]')

Lorenz

Hi Pernelle

You are using *.PlotData in above example to get the stresses. Can we also use dpf?

Regards

Lorenz

Pernelle Marone-Hitz

Hi @Lorenz , yes, DPF could also be used for that purpose. I think I had initially written that script before DPF was released.

Jim Kosloski

I need to do this but more accurately than on an element by element basis. Give the nodal (or integration point stresses) can we determine the volume of that element that is above the threshold value?

Pernelle Marone-Hitz

@Jim Kosloski This should be doable but only through MAPDL / PyMAPDL I think