Calculate center of mass using PyDPF

Ayush Kumar

Calculate center of mass using PyDPF

Ayush Kumar

from ansys.dpf import core as dpf

rst = r"\Path\to\file.rst"

ds = dpf.DataSources(rst)

model = dpf.Model(rst)
dpf_mesh = model.metadata.meshed_region

all_mats = []

mats = dpf_mesh.property_field("mat")
mat_prop = model.operator("mapdl_material_properties")
mat_prop.inputs.materials.connect(mats)

mat_prop.inputs.properties_name.connect("DENS")
mat_field = mat_prop.outputs.properties_value.get_data()[0]
for eid in dpf_mesh.elements.scoping.ids:
    mat_id = mats.get_entity_data_by_id(eid)
    density = mat_field.get_entity_data_by_id(mat_id[0])
    all_mats.append(density)

# Create Density Field
density = dpf.fields_factory.create_scalar_field(num_entities=dpf_mesh.elements.n_elements)
density.location = dpf.locations.elemental
density.scoping.ids = dpf_mesh.elements.scoping.ids
density.data = all_mats

# Element volume
el_vol = dpf.operators.geo.elements_volume(mesh=dpf_mesh)

# Calculate elemental mass
elemental_mass = dpf.operators.math.generalized_inner_product(fieldA=el_vol, fieldB=density)

# Get element centroids
centroids = dpf.operators.result.element_centroids(data_sources=ds)
centroids_f = centroids.outputs.fields_container.get_data()[0]

# Get common scoping
eids = dpf.operators.scoping.intersect() # operator instantiation
eids.inputs.scopingA.connect(centroids_f.scoping)
eids.inputs.scopingB.connect(density.scoping)
eids_out = eids.outputs.intersection.get_data()

# Rescoped to ensure same elements
centroids_r = dpf.operators.scoping.rescope(fields=centroids_f, mesh_scoping=eids_out)
density_r = dpf.operators.scoping.rescope(fields=density, mesh_scoping=eids_out)

# Density * centroids
den_dot_cent = dpf.operators.math.generalized_inner_product(fieldA=centroids_r.outputs.fields_as_field, fieldB=density_r.outputs.fields_as_field)

# Integrate coordinates over element volume
den_dot_cent_int = dpf.operators.geo.integrate_over_elements(field=den_dot_cent, mesh=dpf_mesh)

# Int. across body
all_sum = dpf.operators.math.accumulate(fieldA=den_dot_cent_int)
all_sum_f = all_sum.outputs.field.get_data()
all_sum_f.unit = ""  # Unit causing issues in division

# Total mass
total_mass = dpf.operators.math.accumulate(fieldA=elemental_mass)
total_mass_f = total_mass.outputs.field.get_data()
total_mass_f.unit = ""

# COG
cog = dpf.operators.math.component_wise_divide(fieldA=all_sum_f, fieldB=total_mass_f)