Define an elastic nonlinear material

You can select an elastic nonlinear material from the Fusion Nonlinear Material Library, or create one to your Favorites library.

1. Click (Simulation workspace > Setup tab > Materials panel > Manage Physical Materials) to open the Material Browser.

2. To select a pre-defined material from the Fusion Nonlinear Material Library click the down arrow next to the Home icon, and select Fusion Nonlinear Material Library, then choose a material.

3. Alternatively, create a new material in the Favorites library, as follows:

   1. Choose a material to use as the basis of your nonlinear material and click Copy to Favorites and Edit. The dialog expands to show the properties in the frame on the right side.
   2. Switch to the Physical tab and activate the Advanced Properties check box.
   3. Select the Advanced Properties tab to display additional settings. (Be careful not to click on the checkbox again, or the advanced properties mode will be deactivated.)

4. In the Type drop-down list, choose:

   • Elastic: This option allows you to define points on a stress-strain plot for both compressive (negative) and tensile (positive) response. Do not use this option when plastic deformation is expected (stresses cannot exceed the yield strength of the material). However, unlike the Young's modulus, the points do not have to lie along a straight line, nor do the compressive and tensile stiffness have to be identical. The slope of the curve at all points must remain positive.

5. Specify at least two stress-strain data points, one negative (compressive) and one positive (tensile). Be sure to keep data points sorted into ascending order (most negative to most positive). A zero-zero value is automatically defined at the middle of the curve. You can right-click to insert or delete rows.

   Alternatively, you can click Show Plot to preview the curve and add data points by double-clicking in the display. Adjust data points by dragging the marker in the display or editing the numbers in the table.

   Note:
   • This type of material remains elastic, returning to it's original size and shape when the load is removed. However, you can extrapolate the curve beyond the yield point to prevent solution failures that would occur if the stress and strain go beyond the specified range. As always, you must understand that, in an elastic simulation, resultant stresses beyond yield are not correct and indicate likely material failure.
   • The stiffness can vary nonlinearly (producing a curved plot rather than a straight line).
   • The compressive and tensile stress-strain values can vary in magnitude relative to each other (different behavior in tension and compression).
   • The slope of the curve must remain positive. Negative slopes are not permitted and would cause solution failure.
   • The Nonlinear > Elastic material model is not supported for Event Simulation studies.

6. Click Apply to complete the nonlinear material specifications and OK to exit the Material Browser dialog.