How to extract element nodal forces on selected nodes

[ezyman]

I am using Ansys pdf in Mechanical (2022R1). I run a simple static structural analysis and try to extract nodal element forces on selected nodes. I have written the following script, but the answer I get after running it is wrong. I wonder if I have extracted the forces properly. This issue is almost similar to that raised by @py-1337.

# Import DPF
import mech_dpf
import Ans.DataProcessing as dpf
mech_dpf.setExtAPI(ExtAPI)

analysis_idx = 0

# General Setup / Entry Points
model = ExtAPI.DataModel.Project.Model
geom = model.Geometry
analysis = model.Analyses[analysis_idx]
solution = analysis.Solution

# Get the data source 
dataSource = dpf.DataSources(analysis.ResultFileName)

# Create Named Selection Operator
ns_op = dpf.operators.scoping.on_named_selection()
ns_op.inputs.data_sources.Connect(dataSource)
ns_op.inputs.requested_location.Connect('Nodal')
ns_op.inputs.named_selection_name.Connect('WELDNODES')

# Get node numbers for nodes in named selection
mesh_data = ns_op.outputs.mesh_scoping.GetData()
mesh_data.Ids #  node Ids

# Get complete mesh
model=dpf.Model(dataSource)
mesh = model.Mesh

my_mesh_scoping = dpf.MeshScopingFactory.NodalScoping(mesh_data.Ids)
my_mesh = mesh

enf=dpf.operators.result.element_nodal_forces()
enf.inputs.data_sources.Connect(dataSource)
enf.inputs.mesh_scoping.Connect(my_mesh_scoping)
enf.inputs.mesh.Connect(my_mesh)
enf.inputs.requested_location.Connect(dpf.locations.nodal)

# Get output data
result_fields_container = enf.outputs.fields_container.GetData()[0]
#result_fields_container.GetEntityDataById(89)

# Compute the total element nodal force along the weld line
op = dpf.operators.math.accumulate()
op.inputs.fieldA.Connect(result_fields_container)
enf_total = op.outputs.field.GetData()
enf_total.Data

The output data is wrong, hence "enf_total" is wrong.

Any idea on where I could have done wrong?

[ezyman]

file_rst.zip

[ezyman]

Added an rst zip file and a picture of the model.

[ezyman]

Here is the improved script, but still getting the wrong answer.

# Import DPF
import mech_dpf
import Ans.DataProcessing as dpf
mech_dpf.setExtAPI(ExtAPI)

analysis_idx = 0

# General Setup / Entry Points
model = ExtAPI.DataModel.Project.Model
geom = model.Geometry
analysis = model.Analyses[analysis_idx]
solution = analysis.Solution

# Get the data source (i.e. result file)
dataSource = dpf.DataSources(analysis.ResultFileName)

# Create Named Selection Operator  --- WELD LINE ---
ns_op = dpf.operators.scoping.on_named_selection()
ns_op.inputs.data_sources.Connect(dataSource)
ns_op.inputs.requested_location.Connect('Nodal')
#Name should be in all caps
ns_op.inputs.named_selection_name.Connect('WELDNODES')

# Get node numbers for nodes in named selection
weld_mesh_data = ns_op.outputs.mesh_scoping.GetData()
wm_nodeIds = weld_mesh_data.Ids #  node Ids


# Create Named Selection Operator  --- WELD PLATE ---
ns_wp_op = dpf.operators.scoping.on_named_selection()
ns_wp_op.inputs.data_sources.Connect(dataSource)
ns_wp_op.inputs.requested_location.Connect('Nodal')
ns_wp_op.inputs.named_selection_name.Connect('PLATENODES')

# Get node numbers for nodes in named selection
plate_mesh_data = ns_wp_op.outputs.mesh_scoping.GetData()
pm_nodeIds = plate_mesh_data.Ids #  node Ids

# Get complete mesh
model=dpf.Model(dataSource)
mesh = model.Mesh

# Get plate mesh from scoping
pm_inclusive = 1 # only the elements which have all their nodes in the scoping are included
pm_op = dpf.operators.mesh.from_scoping() # operator instanciation
pm_op.inputs.scoping.Connect(plate_mesh_data)
pm_op.inputs.inclusive.Connect(pm_inclusive)
pm_op.inputs.mesh.Connect(mesh)
pm_mesh = pm_op.outputs.mesh.GetData()

weld_mesh_scoping = dpf.MeshScopingFactory.NodalScoping(wm_nodeIds)

# Instantiate operator   --- element nodal forces ---
enf=dpf.operators.result.element_nodal_forces()

# Make input connections
enf.inputs.data_sources.Connect(dataSource)
enf.inputs.mesh_scoping.Connect(weld_mesh_scoping)
enf.inputs.mesh.Connect(pm_mesh)
enf.inputs.requested_location.Connect("Nodal")

# Get output data
result_fields_container = enf.outputs.fields_container.GetData()
enf_field = result_fields_container[0]
enf_result = enf_field.Data
#enf_field.GetEntityDataById(89)

[pmaroneh]

Hello @ezyman, as this is related to DPF in Mechanical and comparison of results between APDL and Mechanical DPF this should be handled by your official Ansys support channel. Please reach out to Ansys support team through the customer portal or the support email address that has been provided to you.

[ezyman]

Hi @pmaroneh, thank you. I will do it tomorrow.