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Example 2: Basic mesh generation functions

This example shall showcase the core mesh generation functions provided in BeamMe.

In a first step we define the type of beam elements we want to use in this example. The mesh generation functions in BeamMe are agnostic with respect to the employed beam formulation, i.e., every possible beam type can be used with every mesh generation function. For this example we use the Beam3rLine2Line2 class, which represents a two-noded beam element. Hand in hand with the beam type goes the beam material that stores information about the beam-cross section. In this example we mainly use it for defining the radius of the beams for visualization purposes.

from beamme.four_c.element_beam import Beam3rLine2Line2
from beamme.four_c.material import MaterialReissner

beam_type = Beam3rLine2Line2
beam_mat = MaterialReissner

The Mesh class is the core BeamMe class that will hold all the nodes, elements, materials, and geometry sets for the created geometries.

from beamme.core.mesh import Mesh

Straight lines

We already have everything we need to create basic geometries. Let’s start of with the most basic one, a straight line. For that we need the create_beam_mesh_line function. Mesh generation functions always require to provide a mesh to add the created geometry to, a beam type and a beam material. In this example we create a line between the points \(\vv{p} = [0,0,0]\) and \(\vv{q}=[1,0,0]\) with 3 equally spaced beam elements:

from beamme.mesh_creation_functions.beam_line import create_beam_mesh_line

mesh = Mesh()
material = beam_mat(radius=0.01, youngs_modulus=1.0, nu=0.3, density=1.0)
create_beam_mesh_line(mesh, beam_type, material, [0, 0, 0], [1, 0, 0], n_el=3)

{'start': <beamme.core.geometry_set.GeometrySet at 0x7f840471d6a0>,
 'end': <beamme.core.geometry_set.GeometrySet at 0x7f840472e5d0>,
 'line': <beamme.core.geometry_set.GeometrySet at 0x7f840472e710>}

We can see that the mesh creation function returned a dictionary containing GeometrySets. These geometry sets can be used to define boundary conditions. In this case we get the following sets:

• start: A geometry set referring to the start node of the line

• end: A geometry set referring to the end node of the line

• line: A geometry set referring to all created beam elements along the line

Later we will dive closer into GeometrySets.

We can directly have a look at the created geometry with the Mesh.display_pyvista method:

mesh.display_pyvista()

TODO: describe vtu output

TODO