How to loop through PLNSOL and extract maximum deformation

[leoack00]

Hello everyone, I'm doing a harmonic analysis and need to find the maximum deformation in Z for each frequency. Since I have a real and imaginary part and multiple frequencies I will have two plots for each frequency but when I try to loop through it in PyMAPDL it stops after the first mapdl.plnsol. When running the same code in APDL it works and iterates through all frequencies but not in PyMAPDL. I tried using pyvista and the off_screen=True option but the following get command does not take the value from those.

Thanks in advance!

[germa89]

Hi @leoack00

I dont think you need to do plnsol for retriving data. I think you are good to go with Mapdl.prnsol[source].

Then something like:

mapdl.post1()
for count in range(1, endcount, 2):
    mapdl. set(nset = count)
    uz = mapdl.prnsol ( item: "U", comp: "Z").to_array()
    uz_min = uz.min()
    uz_max = uz.max()

    if uz_min - uz_max < 0:
        Real = uz_max
    else:
        Real = uz_min

...
# etc

[mikerife]

@germa89 @leoack00 Initially I had the same idea as germa89. Maybe the only change would be to use the HROUT command prior to solving to store the amplitude and phase in the result file. That way you don't need to calculate it. Mike

[germa89]

@mikerife good idea!

[leoack00]

Hi @germa89 , and @mikerife ,
thanks for the help, it indeed works using prnsol. Changing HROUT to OFF (amplitude and phase) does not change anything for some reason, I changed the set() command accordingly since I don't need to go through all nset numbers but only the ones with the amplitude but I got different results. I also tried using dpf in the meantime but that is giving me different results for a part of the frequency range. Although I solved the problem could I kindly ask you if you can see anything wrong with this code (using dpf) since I'm pretty interested in this in general. It should loop through all subsets and take the maximum and minimum of the Z displacement and calculate which one is larger in absolute values. I tried both, HROUT("OFF") and ("ON") but get the same result.

directory_result = os.path.join(directory, "file.rst")
model = dpf.Model(directory_result)
def_Z = np.empty((1, int(fend/fstep)))
frequencies = np.arange(fstart, fend, fstep)

for i in range(1, int(fend/fstep+1)):
    load_step_id = 1
    subset_id = i

    metadata = model.metadata
    tf = model.metadata.time_freq_support
    my_scoping = dpf.time_freq_scoping_factory.scoping_by_step_and_substep(load_step_id, subset_id, tf)

    disp_op = dpf.operators.result.displacement_Z()
    disp_op.inputs.time_scoping.connect(my_scoping)
    max_fc_op = dpf.operators.min_max.min_max_fc(disp_op)

    workflow = dpf.Workflow()
    workflow.add_operators([disp_op, max_fc_op])

    workflow.set_input_name("data_sources", disp_op.inputs.data_sources)
    workflow.set_output_name("min", max_fc_op.outputs.field_min)
    workflow.set_output_name("max", max_fc_op.outputs.field_max)

    data_src = dpf.data_sources.DataSources(directory_result)
    workflow.connect("data_sources", data_src)
    min_field = workflow.get_output("min", dpf.types.field)

    max_field = workflow.get_output("max", dpf.types.field)

    abs_max_min = np.max(np.abs(min_field.data))
    abs_max_max = np.max(np.abs(max_field.data))

    def_Z[0, i-1] = max(abs_max_min, abs_max_max)

Thanks for your time and the help! Leo

[germa89]

I'm sorry I'm no expert in DPF :(

[leoack00]

no problem, appreciate the help with the initial question!