1D meshes for lattice bodies

In the Modeling application, you can use the Lattice command to create CAD convergent bodies with a lattice structure. When you create a FEM file from a lattice convergent body, the software automatically creates a 1D lattice mesh from the lattice structures.

A lattice is a thin, truss-like shape that you can use to model parts that can be produced using additive manufacturing technologies (3D printing). Lattice parts are lightweight, though they maintain structural strength and integrity. Lattice bodies are formed from a cellular structure of connected rods. You can choose from a number of different lattice cell types, such as:

The software creates a single 1D element for each lattice rod. The software connects these 1D elements at shared nodes, where appropriate.

CAD convergent bodies with lattice	1D mesh created automatically from the lattice in Pre/Post

Lattice mesh material and physical properties

During the FEM file creation process, Pre/Post reads the following data from the lattice convergent body and uses this data to create the 1D lattice mesh:

• The material assigned to the parent part, if available.

• The beam start locations, end locations, and the beam connectivity data.

• Beam section data. For lattice bodies with a constant thickness value, the software automatically creates a physical property table with a rod cross section. The software uses the Rod Diameter value from the Lattice dialog box in the Modeling application to define the diameter of the beam cross section.For lattice bodies with variable radii, the software creates a physical property table with a tapered beam section. The software uses Element Associated Data overrides to associate the cross section with the 1D elements.

Working with the lattice mesh

• A 1D lattice mesh is FE-based and is not associated with any geometry. The software does not update FE-based meshes.You can use manual meshing commands, such as Mode Node or Element Translate to modify the 1D elements in the lattice mesh. The software automatically locks the mesh to prevent automatic updates if you modify the elements or nodes in the lattice mesh.

• The software stores lattice mesh and collector data in a Lattice Mesh node under the u1D Collectors node in the Simulation Navigator.

Lattice mesh quality

The quality of the lattice in the CAD convergent body directly affects the quality of the 1D lattice mesh that Pre/Post creates. You should use the settings in the Lattice dialog box in the Modeling task to control the characteristics of the lattice. For example, you can use the Remove Dangling Rods at Selected Faces option to remove all rods that are connected at only one end to the lattice and touching one of the faces of the body that bounds the lattice.

Deleting the 1D lattice mesh

You can use the Delete Element command to manually remove selected elements from the 1D lattice mesh. You can also delete the entire mesh from the Simulation Navigator.

• If you delete a 1D lattice mesh, the software deletes the mesh and any connection elements between the lattice mesh and any surrounding geometry.The software excludes lattice polygon bodies that are related to deleted 1D lattice meshes from processing when you edit or update the FEM file. The software places the lattice polygon body in the Excluded Geometry folder in the Simulation Navigator.Note: To recreate a lattice mesh on an excluded lattice body, right-click the body in the Excluded Folder and select Create.

• If you delete the lattice convergent body from the CAD part file, or if you remove the lattice convergent body from the FEM file, the software deletes the 1D lattice mesh and any connection elements between the lattice mesh and any surrounding geometry when:

Locking and unlocking lattice meshes

You can lock and unlock lattice meshes, just as you can other types of meshes. The software automatically locks a 1D lattice mesh if you modify it using one of the manual node or element commands, such as Move Node.

Note:

To unlock a lattice mesh, you must load the associated CAD part.

Connecting a lattice mesh to adjacent meshes

You can use the 1D Connection command to connect the 1D lattice mesh to meshes on adjacent polygon faces. Use the 1D Mesh to Face option in the Type list in the 1D Connection dialog box to connect nodes in the 1D mesh to nodes on the selected polygon faces. The software projects the nodes onto the specified target face along a normal. If the software finds a node on the target face within the specified Node to Face Proximity distance from the projected node, the software creates a connection element between the nodes.

1D lattice mesh and 2D mesh on the surrounding body	1D rod elements connect the nodes on the lattice mesh to the nodes in the 2D mesh on the solid body

Where do I find it?

Application	Pre/Post
Prerequisite	A FEM file as the work part and displayed partAn existing CAD convergent body with lattice informationSimcenter Nastran, MSC Nastran, Simcenter Samcef, ANSYS, or Abaqus as the specified solver

Quick links

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Pre/Post video examples

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1D meshes for lattice bodies, Simcenter 3D 2021.1 Series

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