Lattice Search
Find unit cells to meet the performance and aesthetic criteria for your designs in Design Engine's metamaterials library.
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Launch Lattice Search from the quick-access button on the upper right of the design user interface.
You can also launch Lattice Search from inside the Strut Lattice tool, under Lattice Type. This will enable you to apply unit cell from your search directly to an input mesh, as shown in the demo video below.
Thousands of lattices are available in the metamaterials library and Design Engine provides filter options to narrow your results by performance and by lattice parameters.
Two filters are available to search by stiffness within the unit cell's stress-strain curve: modulus and stress at 25% strain. You can also search by volume fraction to estimate the weight of the lattice.
Simulated Testing
In order to have performance data for thousands of lattices, the library utilizes simulated testing.
Results yield a stress/strain curve and volume fraction for each lattice. For more details, read Building Carbon's Metamaterials Library.
Because data is based on simulations, final part performance may vary.
Our simulated mechanical response data reasonably matched experimental data on the small set of lattices we tested in a physical setting. However, these tests were performed with ideal, simple parts in a controlled environment. We do not expect the precise numbers shown to accurately describe performance of parts that are more complex or used in less ideal settings. The data like the stress-strain curves shown in Design Engine are best used as a comparative tool in evaluating a lattice’s performance relative to other lattices. Actual lattice behavior depends on specific use and is subject to variation inherent in manufacturing processes and different environments in which products are used. Users should validate lattice behavior in settings specific to their needs.
For more information on stress-strain graphs, reference Stress-Strain Curves.
For more information on volume fraction per lattice type, reference Mass Comparison
If you have a particular foam in mind that you are trying to replicate, see the Foam to Lattice Workflow example below.
Note that combining lattices with skins or using thicker boundary struts than the body of the lattice, can make the structure feel slightly stiffer in performance.
Standard lattice parameters can also be used to filter down results.
Cell Size
Narrow the cell sizes that appear in search results based on your part geometry and manufacturability.
Strut Diameter
Narrow the strut diameters that appear in search results based on your material.
Lattice Search catalogs lattice types for both tetrahedron mesh and hexahedron mesh scaffold types.
Scaffold Type
Toggle between tet and hex scaffold type to search per mesh preference.
Hybrids are only available for tet mesh types.
The primary lattice types available will vary to match the selected scaffold type.
Tet Lattice Types
There are more options than just the five primary tet lattice types available in the Strut Lattice operation.
- Two additional tet lattice types appear in the library: Kelvin (Tet) and Star (Tet)
- Hybridized lattice types are also available in many combinations
Hybrid Lattice Types
Hybridized lattices are available using all seven tetrahedron lattice types: Icosahedral | Kagome | Kelvin (Tet) | Rhombic | Star (Tet) | Tetrahedral | Voronoi
- The example here is 1/3 Star and 2/3 Voronoi. The unit cells of each type merge together to create a unique unit cell in the noted proportions.
- Hybrid lattices are named by their components, using the first three letters of each lattice type, followed by their proportions as a percentage.
- In this example: StaVor_3366
Hex Lattice Types
To create a lattice using a Hex Mesh, you must generate the Hex Mesh via the Hex Mesh operation before you can select and apply unit cell parameters via the Strut Lattice operation.
Lattice Search assumes a gridded Hex Mesh with equal XYZ hexahedron dimensions.
This equal-sided cuboid is the cell size of the strut lattice unit cell shown in the meta-materials library (MML).
When reviewing lattice performance in the MML, reference the closest approximate cell size to your hex mesh.
Note that when using the apply unit cell option when launching Lattice Search directly from the Strut Lattice operation, the cell size will not be applied, as the cell size of your Hex Mesh will be used. Only the lattice type and strut diameter will carry through.
Your actual hex lattice performance may vary depending on the type of hex mesh you use and the size and proportions of the hexahedrons in your hex mesh.
Note that there is a Star lattice type available for both tet and hex scaffold types.
Elastomers
The metamaterials library currently catalogs lattices in Carbon's elastomeric materials:
Use EPU 44 results for EPU 46.
For more guidance and manufacturability information, reference the Lattice Parameters lesson.
Note that using Lattice Search for a zone will only apply the lattice type to the zone, rather than all unit cell parameters.
When performance data is not available within the metamaterials library, a button to request performance data is available within the Strut Lattice tool.
One of the key challenges that designers face when designing with a lattice is not having a clear path to mimic the mechanical performance and aesthetics desired. Searching a vast library can be a daunting task if you don't have specific performance criteria in mind.
A common path in lattice design is to have foam characteristics in mind as a benchmark for finding lattices that perform in a similar capacity.
Carbon tested a cross section of common foams to capture data in the same format as the library's lattice simulation data, to provide a reference point for finding unit cells. For more details on Carbon’s testing and data modeling, reference this white paper.
Filter by Foam
In the materials filter, click on foam to see all foams available in the metamaterials library.
Several of the foams we tested are from broad generic categories. To provide more context, below are the retailer specifications for these foams.
Generic Foam | Common Application | Retailer Specs |
|---|---|---|
Closed Cell Foam (EVA) | Exercise Mats | EVA Foam "Firm" Density: 2.0 pcf (0.032 g/cc) |
High Density Foam | Furniture Cushions | EverFlex V54 54 ILD (240 N) Density: 2.9 pcf (0.046 g/cc) |
Latex Foam | Mattresses and Cushions | N28 28 ILD (125 N) Density: 6 pcf (0.096 g/cc) |
Memory Foam | Mattresses and Cushions | 13 ILD (58 N) Density: 2.5 pcf (0.040 g/cc) |
Neoprene Foam | Gaskets | 3 psi to compress 25% (20.7 kPa*) Density: 10.0 pcf (0.160 g/cc) |
Packing Foam | Packing/Shipping | Y37ch Foam 35 ILD (156 N) Density: 1.2 pcf (0.019 g/cc) |
Rebond Foam | Carpet Padding | 90 ILD (400 N) Density: 8.0 pcf (0.128 g/cc) |
* Results of Carbon testing did not match retailer specs. Testing conditions may vary results.
Filter Foam Performance
- Select foam to match
- Check the box to compare
- Filter modulus range close to foam
- Choose a range +/- a couple hundred because the linear elastic range is generally a small part of the data set.
- Filter stress at 25% strain range close to foam
- Choose a tight range for best results
Filter Lattice Parameters
- Select materials for application
- Energy return in example
- Select cell size range to suit geometry
- Select strut diameter range to suit resin and cell size range
- Select volume fraction range to suit weight goals
- Optionally filter to preferred lattice types
Compare Results
- Select up to 5 options to compare foam
- Highlight foam for clarity
- Hover cursor over strain at 50%
- Match the closest compression metrics
- Closest lattice
- Apply unit cell to generate strut lattice
Check Unit Cell Manufacturability
In this example, Voronoi with a 10mm cell size and 0.8mm strut diameter closely matches our high density foam.
- Check that the unit cell conforms well to your design space
- Verify manufacturability for the unit cell
- In this case, the parameters are well within the range of Voronoi's manufacturability in Carbon's DLS production
For manufacturability information for tet lattices, reference Unit Cell Manufacturability.
Align Data If you have your own foam testing data, you may need to align your data to match the format in Design Engine before comparing data.
Stress - Strain
Data may be in Force (N) - Displacement (mm) units rather than Stress(kPa) - Strain (%). The same curve may appear slightly different when plotted in different units, which can throw off your search results.
Stress
Divide force by the surface area of the testing apparatus on the sample.
Strain
Convert the displacement dimension to a percentage of the sample thickness.
Plot Curve and Compare to Lattices
- Plot stress-strain curve
- Plot data points at 2, 4, 6... 60% strain to match Design Engine graphs
- Use the cycle 2 curve if you have multiple cycles
