Calibrating data for hyperelasticity with permanent set

The hyperelasticity with permanent set calibration behavior enables you to extract plastic and hyperelastic material behaviors and Mullins effect from uniaxial and biaxial data sets of the loading, unloading, and reloading of elastomers and thermoplastics. You can extract data from a uniaxial test, a biaxial test, or from both types of tests. The calibration process includes the following steps:

  1. Upload uniaxial and/or biaxial test data files into Abaqus/CAE as new data sets.

  2. Extract the loading, unloading, and reloading cycles and the permanent set data from the data files you provide and create separate data sets for the load, unload, and reload phase of every cycle.

  3. If desired, select any data cycles that you want to exclude from calculations of material behavior.

  4. Select the yield point from the viewport and, if desired, edit individual points on the primary loading data set to create a smoother curve. The permanent set curves are based upon the current yield point, so these curves also change when you select a new yield point.

  5. Once you determine the test data sets that you want to use for deriving material behaviors and you specify primary curve options, you can derive material behaviors from the selected data. Abaqus/CAE maps plastic, hyperelastic, and Mullins effect material behaviors to the material you select.

Related Topics
Defining classical metal plasticity
In Other Guides
Hyperelastic behavior of rubberlike materials
Mullins effect

  1. From the Model Tree, expand the Calibrations container and double-click Behaviors.

    The Create Calibration Behavior dialog box appears.

  2. Enter a name for the material calibration behavior, select Hyperelasticity with permanent set, and click Continue.

    The Edit Behavior dialog box appears.

  3. Perform the following steps from the Uniaxial or Biaxial tabbed page:

    1. Select the cycle from which to extract data to calibrate the Mullins effect. By default, Abaqus/CAE extracts the last unloading and reloading curves.

      • Select Last cycle found to extract the last unloading and reloading curves from each strain level in the supplied test data.

      • Select First cycle found to extract the first unloading and reloading curves from each strain level in the supplied test data.

    2. Expand the Data set list, and select the data from which you want to calculate the calibration values for uniaxial or biaxial data tests.
    3. Click .

      Abaqus/CAE extracts the primary loading curve, the specified unloading and reloading curves for each cyclic strain level, and the permanent set curves, then creates new calibration data sets for each component of each cyclic strain level. Each new data set is available in the Uniaxial Test Data Sets or Biaxial Test Data Sets options and is plotted in the viewport.

    4. Toggle on the individual loading, unloading, or reloading data sets that you want to include in the material calibration calculations. As you toggle on a data set, Abaqus/CAE displays its corresponding X–Y curve in the viewport. You can select any of the following:

      • Select All to include all the raw data found in the selected test data file.

      • Select Primary to include data from the primary loading curve.

      • Select Unloading to include data from the unloading curves for each cyclic strain level, or expand this container to select individual unloading curves.

      • Select Reloading to include data from the reloading curves for each cyclic strain level, or expand this container to select individual reloading curves.

      • Select Permanent Set to include data from both permanent set curves, or expand this container to select either stress- or strain-related components of permanent set.

    5. From the Yield Point options, do either of the following:

      • Click , and select the yield point on the primary curve from the viewport.

      • Click , and enter either the Strain or Stress value; Abaqus/CAE calculates the other value from the primary curve and populates the remaining field.

  4. If desired, extract a second data set from the Uniaxial or Biaxial tabbed page.

  5. If you extracted both uniaxial and biaxial test data, Abaqus/CAE applies the data equally by default in the calculations of material behaviors. Perform the following steps from the Options tabbed page if you want one data set to have greater weight in these calculations:

    1. In the Material Properties options, drag the Weight slider toward the type of data (uniaxial or biaxial) that you want to assign greater weight in the material behavior calculations.
    2. Specify whether the selection of relative weight is based on a linear interpolation or a logarithmic interpolation.

  6. From the Material list, select the material definition to which you want to apply this calibration behavior; or click to create a new material definition for this calibration behavior. For more information about defining a new material model, see Creating or editing a material.

  7. Click OK.

    Abaqus/CAE updates the new calibration behavior and maps the hyperelasticity with permanent set calibration behavior parameters to the Hyperelastic, Plastic, and Mullins Effect material behaviors of that material definition.

    Note:

    Any hyperelastic, plastic, or Mullins effect material behaviors in the selected material are overwritten when you map data from a calibration behavior to the material definition.