Example B-2: Linear Displacement BC

This example demonstrates how to apply the constraints for a linear displacement BC to a part.

These constraints can then be used for applying the boundary conditions to the part. A sample script fot Abaqus’ Python Scripting Interface is provided for clarity.

See the Boundary Conditions section for a thorough explanation of this subject.

The model created in this example is similar to Example A-1. A 2D part with a shape of 50×100 voxels is created with a base material of 1 and a voxel size of 0.02 units in all directions. The parameter log_debug is set to True for demonstration purposes.

Afterwards, the linear displacement BC is requested using the following statement:

part.add_bc(bc_type='Linear Displacement')

The part is then exported to an Abaqus™ input file in 2D mode with CPE4R elements. The Non-Empty elements (which happens to be the whole model), are requested to be exported.

The code can be found in the examples folder of the main repository. It is also included below:

"""Script for Example B-2: Linear Displacement BC."""

from vcams.voxelpart import VoxelPart

# Create the part.
part = VoxelPart(size=(50, 100), base_material=1, voxel_size=(0.02, 0.02), name='Ex B-2 Linear Displacement BC',
                 description='Example B-2: A 2D part on which a linear displacement BC is applied.', log_debug=True)

# Ask for a linear displacement BC to be applied to the model.
part.add_bc(bc_type='Linear Displacement')

# Output the part.
part.output_abaqus_inp(file_name='ex_b2_lindisp',
                       elem_code='CPE4R', dim='2D',
                       material_elem_sets='Non-Empty')

After importing the resulting file in Abaqus™, we can define a step and apply loading on the dummy nodes using the following Python commands:

# Define some parameters for ease of use.
model = mdb.models['ex_b2_lindisp']  # Make sure the name is correct.
assembly = model.rootAssembly

# Fix RP-0 in place.
model.EncastreBC(name='Fixed-BC', createStepName='Initial', region=assembly.sets['RP0-NodeSet'])

# Apply the displacement vector (1.1, 2.2) to RP-1.
# Note that the BC is in the step named 'Step-1' and only u1 and u2 are valid displacements.
model.DisplacementBC(name='Disp-BC', createStepName='Step-1',
    region=assembly.sets['RP1-NodeSet'],
    u1=1.1, u2=2.2)