- Analyzing complex lattice structures.
- Exporting material properties.
| Pros | Cons |
|---|---|
| A fast method of analyzing lattices. | More setup steps. |
| Works for any type of lattice. | Least accurate option compared to using a solid element or beam element simulations. |
| Works on large and high-density lattice structures. | No edge effects. |
| No stress concentrations. | |
| Ignores blend lattice-wall radius. | |
| Lattice thickness must be uniform. |
- The block has the following inputs :
- Unit Cell Model: The unit cell’s simulation model has domain, mesh, attribute (solid), and material properties.
- Design Volume: This is the Implicit Body that envelops the boundaries of the unit cell exactly. This is typically a box. Unit cells with rounded corners are typically trimmed to fit a box.
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- Tolerance: This is the search tolerance to establish a rigid connection between the periodic boundaries of the unit cell. The tolerance value should be large enough to capture the nodes on the periodic boundaries but small enough to avoid over-constraining these boundaries. A recommended value is 10% of the element size of the unit cell mesh.
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- Mechanical and Thermal checkboxes: By default, the block has the Mechanical option checked to calculate the effective elastic properties. Optionally, checking the Thermal option will prompt the block to calculate the effective Thermal properties like the unit cell’s anisotropic conductivity and specific heat capacity.
- Periodicity in all directions: While this method offers a convenient way to cut down the computational effort for large lattice structure simulation, it is best applied to situations where this lattice is periodic in all three orthogonal directions.
- Tolerance setting: The tolerance setting defines the maximum distance between the nodes on the periodic boundaries that will be connected. Typically, the default tolerance value of 0.01mm should work for most cases, but a recommended tolerance size is about 10% of the mesh size. A method to check that the tolerance value is appropriate to capture the periodic boundaries is to increase the deformation scale of any Homogenization result. The boundaries would deform uniformly if the tolerance is right (image on the left). If not, there would be disconnected nodes in the boundary (image on the right). If the tolerance value is too large, the block will report the following error: “Error in solving the linear system of equations. The system is not positive definite.”
- Exporting Material Properties: Exporting the anisotropic material properties generated by the homogenized unit cell block is possible. This can be achieved through the Export Material block, as described in this support article.
Example File
Example 1 - Bend Testing a Lattice Panel
| Model | S11 Stress, MPa | Max Displacement, mm | Mesh Time, s | Solve Time, s |
|---|---|---|---|---|
| Macromodel | 131.37 | 1.47 | 15 | 340 |
| Micromodel | 130.22 | 1.43 | 46 | 45 |
Example 2 - Thermal Analysis of a Porous Structure
