How to create Custom Field Optimization Component with a Custom Graph Unit Cell

Objective:

Creating Custom Field Optimization Component with a Custom Graph Unit Cell

Applies to:

Field Optimization

Procedure:

This article uses nTop Automate, Topology Optimization, and Field Optimization. Here is a list of resources that are suggested pre-requisite before going through the article.

Before we begin going through the article, we recommend you download the files that are needed to follow along from here. We recommend you create a new folder, as we will create multiple files and run scripts. We should place all the files and scripts in the same folder.

1. Generate Custom Unit Cell

2. Gathering Homogenization Data

3. Creating Parametric FE Component

3.1. Updating the Material Model

3.2. Updating the Porosity Function

3.3. Updating the Geometry Function

3.4. Updating the Parametric Lattice Component

4. How to Use Custom Parametric Lattice Component

1. Generate Custom Unit Cell

We will start by generating a custom unit cell to be used as part of your field optimization workflow.

Note: This Support article covers graph unit cells only.

Following the support article, you can generate your Custom Graph Unit Cell. For this example, you can download the “custom_graph_unit_cell.ntop” file as a starter file and change the Line Segments and Domain input if you wish to change. We need to ensure that the unit cell is periodic.
Save and close the file.

2. Gathering Homogenization Data

In this section, you will be using nTop Automate to run a series of homogenization. The homogenization data will be used in the field optimization process. For more information, see Field Optimization FAQ.

Open “homogenize_periodic_lattice.ntop” from the downloaded files.
Import the custom unit cell (“custom_unit_cell.ntop”) generated in the previous step.

Click the Show Left Bar icon on the Top-Left corner next to the Hamburger icon.
Switch to the Imports tab, then click the Import Block.
Select the “custom_unit_cell.ntop” from the File Explorer.

Drag and drop the unit cell into the unit cell variable

Save and close the file.
Open “run_data_collection.py” in a Python IDE. We recommend downloading one of the following free software:

Thonny (recommended for beginners)
Spyder
Visual Studio Code

Examples in this article are done using Visual Studio Code

Note: Ensure the file “homogenize_periodic_lattice.ntop” is in the same directory as “run_data_collection.py.” 7. Enter the number of discretizations over the Poisson ratio and thickness you would like and run the Python script. The lines of code to adjust are annotated below: Lines 43 and 44 in the provided code replace the bounds and number of discretizations for the parameter sweep. The variables corresponding to the values are listed below: Note: The minimum number of discretizations for thickness should be at least five but ideally greater than 10. Parameter1_all = np.linspace(min thickness/cell size, max thickness/cell size, number of steps) Poisson_ratio_all = np.linspace(min poisson ratio, max poisson ratio, number of steps) Note: The Poisson ratios should include that of your intended printing material. Example code is seen below:

 parameter1_all = np.linspace(0.05, 1.5, 2)
 poisson_ratio_all = np.linspace(0.1, .4, 2)

After running the Python script, a “combined.csv” file with values should be available in the file directory where the Python program was run.

Warning: The combined.csv, as well as the individual *.csv files in the “Result_Data” folder, must be deleted before running the script with different settings or for a different unit cell to prevent it from appending.