How to Set Material Properties in FreeCAD FEM

Setting up material properties such as Young's modulus and Poisson's ratio in FreeCAD's Finite Element Method (FEM) workbench is a fundamental step for running structural simulations. This guide walks you through navigating the FEM workbench, generating a material object, selecting standard presets, assigning custom elastic values, and mapping those properties directly to your 3D geometry.

Step 1: Initialize the FEM Analysis Container

Before defining any physics or material data, you must have an active analysis container:

  1. Open your 3D model in FreeCAD.
  2. Switch to the FEM Workbench using the workbench dropdown selector at the top of the interface.
  3. Click the Analysis container button (represented by a yellow folder with a red "A") or select Model > Analysis container from the top menu. This creates the primary tree structure required for your simulation setup.

Step 2: Create a Solid Material Object

Once the analysis container exists, you can add material parameters:

  1. Ensure your analysis container is selected in the Model tree.
  2. Click the Material for solid button in the toolbar (represented by three colored spheres) or navigate to Model > Material for solid.
  3. A new material object named MaterialSolid will appear under your analysis container, and the material settings panel will open in the Tasks tab on the left.

Step 3: Configure Young's Modulus and Poisson's Ratio

In the material task panel, you have two approaches for defining mechanical values:

  • Using a Preset: Click the Material dropdown menu to select a predefined substance (such as Steel-C45, Aluminum-Generic, or Titanium). Selecting a preset automatically populates physical constants including Young's modulus, Poisson's ratio, and density.
  • Entering Custom Properties: To input your own Young's modulus, locate the Young's modulus input field in the task panel. Enter your value along with the relevant unit (for example, 210 GPa or 70000 MPa). FreeCAD handles unit conversions automatically based on your application preferences. Ensure you also provide a valid Poisson's ratio (typically between 0.25 and 0.35 for isotropic metals), as both properties are mathematically required for linear elastic solvers.

Step 4: Assign Material to Geometry

By default, FreeCAD applies the defined material to all active solid bodies within the analysis. If your model contains multiple parts or you want to assign the material to specific solids:

  1. Look at the Geometry section at the bottom of the material task panel.
  2. Click Add, then click the target solid body in the 3D viewport.
  3. Verify that the correct object appears in the selection list.
  4. Click OK to confirm your changes and save the material configuration to the model tree.