This section describes how to extract material behavior constants from calibration data sets. You can define calibration behaviors for the following material models:
Isotropic elastic
Isotropic elastic-plastic
Hyperelasticity with permanent set
You can also add support for custom calibration behaviors, which appear as new options in the Calibration Behavior dialog box. For more information, see "Creating custom material calibration plug-ins in Abaqus/CAE" in the Dassault Systèmes Knowledge Base at www.3ds.com/support/knowledge-base.
Abaqus/CAE assumes that the material is fully incompressible when it calculates material properties and plots material response curves from test data other than the volumetric test.
The isotropic elastic calibration behavior enables you to derive isotropic elastic data (Young's modulus and Poisson's ratio) from calibration data sets and to apply these material constants to the elastic material properties of a material definition in your model.
To calibrate data for isotropic elastic material behavior:
From the Model Tree, expand the Calibrations container and double-click Behaviors.
The Create Calibration Behavior dialog box appears.
Enter a name for the material calibration behavior, select Elastic Isotropic, and click Continue.
The Edit Behavior dialog box appears.
From the Parameter Set 1 options, do the following to calculate a value for Young's modulus:
From the Data set list, select the data from which you want to calculate Young's modulus.
Click 
.
Abaqus/CAE computes Young's modulus and displays its value to the right of the Young's modulus label.
From the Parameter Set 2 options, do the following to calculate a value for Poisson's ratio:
From the Data set list, select the data from which you want to calculate Poisson's ratio.
Click .
Abaqus/CAE computes Poisson's ratio and displays its value to the right of the Poisson's ratio label.
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,” Section 12.7.1.
Click OK to save the isotropic elastic behaviors to the selected material model.
Abaqus/CAE adds the new behavior to the model tree and adds the specified Young's modulus and Poisson's ratio to the Elastic material properties for the specified material.
The isotropic elastic-plastic calibration behavior enables you to derive isotropic elastic and plastic material behaviors.
To calibrate data for isotropic elastic-plastic material behavior:
From the Model Tree, expand the Calibrations container and double-click Behaviors.
The Create Calibration Behavior dialog box appears.
Enter a name for the material calibration behavior, select Elastic Plastic Isotropic, and click Continue.
The Edit Behavior dialog box appears.
From the Elastic-Plastic Data options, do the following:
Expand the Data set list and select the data from which you want to calculate the first set of calibration values.
From the Ultimate point options, either click to calculate the ultimate point automatically or click 
and select the ultimate point from the viewport.
Abaqus/CAE plots the ultimate point in the viewport and displays its coordinates in the dialog box.
From the Yield point options, click and pick the yield point from the viewport.
Abaqus/CAE plots a line between the origin and the yield point in the viewport, displays the coordinates for the yield point in the dialog box, and calculates the Young's modulus and displays its value to the right of the Young's modulus label.
Select the plastic points for this material calibration by doing either of the following:
Drag the Plastic points slider to the right to calculate a greater number of plastic points or drag the slider to the left to calculate fewer plastic points.
Click to pick plastic points from the viewport.
From the Poisson's Ratio Data options, do the following:
From the Data set list, select the data from which you want to calculate Poisson's ratio.
Click .
Abaqus/CAE computes the Poisson's ratio, displays its value in the Poisson's ratio field, and plots it in the viewport. If desired, you can adjust the calculated value of Poisson's ratio by changing the value in the field.
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,” Section 12.7.1.
Click OK.
Abaqus/CAE updates the new calibration behavior. If you specified a material definition, Abaqus/CAE maps the isotropic elastic-plastic calibration behavior parameters to the Elastic and Plastic material behaviors of that material definition.
Note: Any elastic or plastic material behaviors in the selected material are overwritten when you map data from a calibration behavior to the material definition.
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:
Upload uniaxial and/or biaxial test data files into Abaqus/CAE as new data sets.
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.
If desired, select any data cycles that you want to exclude from calculations of material behavior.
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.
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.
To calibrate data for hyperelasticity with permanent set:
From the Model Tree, expand the Calibrations container and double-click Behaviors.
The Create Calibration Behavior dialog box appears.
Enter a name for the material calibration behavior, select Hyperelasticity with permanent set, and click Continue.
The Edit Behavior dialog box appears.
Perform the following steps from the Uniaxial or Biaxial tabbed page:
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.
Expand the Data set list, and select the data from which you want to calculate the calibration values for uniaxial or biaxial data tests.
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.
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.
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.
If desired, extract a second data set from the Uniaxial or Biaxial tabbed page.
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:
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.
Specify whether the selection of relative weight is based on a linear interpolation or a logarithmic interpolation.
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,” Section 12.7.1.
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.