Defining Stress-Strain Curves

Stress-strain curves are available with the following material models: Nonlinear Elastic, Plasticity - von Mises, and Plasticity - Tresca.

To define a stress-strain curve:

  1. In the Material dialog box, right-click Custom Materials and select New Category. If needed, rename the New Category folder.
  2. Right-click the newly defined category and select New Material.
  3. On the Properties tab, do the following:
    1. Set Model Type to either Nonlinear Elastic, Plasticity - von Mises, or Plasticity - Tresca.
    2. Select the desired Units.
    3. Click Create Stress-Strain Curve.
      The Tables & Curves tab is active and Stress-Strain Curve is selected in Type.
  4. In Table data, do the following:
    1. Select the desired stress in Units.
    2. Enter the strain and stress data pairs in the table. For large strain formulation, enter the logarithmic strain data.
    3. To open a new row, double-click any cell in the Points column.
    4. Click File to read data from a *.dat text file with two columns of data.
    5. Click View to view the curve.
  5. To save the material to a material library, click Save.
  6. Click Apply.
  7. Click Close.
  • During the solution, when values for the stress-strain data exceed the last datapoint of the curve, the software extrapolates linearly the last couple of data points on the stress-strain curve you enter.
  • For Hyperelastic Ogden and Hyperelastic Mooney Rivlin material models, you can define stretch ratio (deformed length/undeformed length) versus nominal stress (force/initial area) data pairs based on experimental data from specimen tests: simple tension, planar tension or pure shear, and biaxial tension.