This article will give you an overview of the various methods of simulating lattice structures in nTop Platform, going over the pros and cons of each method with a basic workflow mentioned below.
Solid elements are a volumetric finite element mesh of the entire lattice structure.
- Small mesh size is required to capture the detail of the lattice
Set up an FE Solid Component block in the FE Model. Depending on the model, some mesh errors may occur. Follow these steps if so:
- Use Remesh Surface block after Mesh from Implicit Body
- Volume Mesh block may fail, if so, you can repair the mesh through Voxel Grid from Implicit and Remesh Surface or use the slower, more robust, Robust Tetrahedral Mesh
Beam elements are finite element nodes along lattice vertices, connected by lattice beams. This method greatly reduces the number of elements from a typical volume mesh, but it ignores certain mechanical behavior like edge effects and stress concentrations in the lattice. FE nodes will be placed at the end points of each beam, along with node(s) along the subdivisions of the beam. You can choose the number of subdivisions as an input to the FE Lattice Mesh block, which will be arrayed as demonstrated in the image below.
Set up an FE Lattice Component in FE Model. Keep in mind the lattice beam thickness is a field input in the FE Lattice Component block. You will need to correctly isolate and trim the lattice elements.
- Use Trim Lattice to make sure the lattice elements lie within the volume of the Lattice Structure
- If you get a warning about short lattice beams, use Collapse Lattice Vertices with a threshold much lower than the unit cell size
To create a homogenized simulation, run a Solid FEA simulation on a single unit cell of the lattice, and generate effective material properties of the unit cell. Next, run a second Solid FEA simulation on the bulk lattice structure volume using the effective material properties (from the first simulation).
Use FE Solid Component with the Material chip from the Homogenization block.
- Works best with many unit cells
- Good for comparing different lattice types
Check out this nTop Live and example file for more on Homogenization.