Maximum principal stress or strain damage

From the menu bar in the Edit Material dialog box, select Mechanical Damage for Traction Separation Laws Maxps Damage or Maxpe Damage.

(For information on displaying the Edit Material dialog box, see Creating or editing a material.)

Enter the Tolerance. The value should be equal to the tolerance within which the damage initiation criterion must be satisfied.

To define the separate tolerance used for crack growth, toggle on Growth Tolerance and enter the Growth Tolerance.

If this parameter is included but no value is specified, keep the toggle on for default.

To define the separate tolerance used for unstable crack growth, toggle on Unstable Growth Tolerance and enter the Unstable Growth Tolerance.

If this parameter is included but no value is specified, keep the toggle on for infinite.

Select the arrow to the right of the Position field, and select the method for computing the stress/strain fields ahead of the crack tip to determine if the damage initiation criterion is satisfied and to determine the crack propagation direction (if needed):

Select Centroid to use the stress/strain at the element centroid.
Select Crack tip to use the stress/strain extrapolated to the crack tip.
Select Combined to use the stress/strain extrapolated to the crack tip to determine if the damage initiation criterion is satisfied and to use the stress/strain at the element centroid to determine the crack propagation direction (if needed).
Select Nonlocal to use the stress/strain extrapolated to the crack tip to determine if the damage initiation criterion is satisfied and to use the stress/strain averaged over a group of elements around the crack tip in the enriched region to determine the crack propagation direction (if needed).

To define material damage data that depend on temperature, toggle on Use temperature-dependent data.

A column labeled Temp appears in the Data table.

To define behavior data that depend on field variables, click the arrows to the right of the Number of field variables field to increase or decrease the number of field variables.

Field variable columns appear in the Data table.

Enter the Angsmooth. The value should be equal to the maximum allowed difference (in degrees) below which the normals of the crack facets are included in the moving least-squares approximation to smooth out the crack normals to obtain the crack propagation direction along the crack front, and it can be used only in conjunction with Position=Nonlocal in enriched elements.

Enter the R Crack Direction. The value should be equal to the radius around the crack tip within which the elements are included for calculating the averaged stress/strain and for smoothing out the normals of the individual crack facets along the crack front used to obtain the crack propagation direction, and it can be used only in conjunction with Position=Nonlocal.

Select the arrow to the right of the IniSmooth field, and it can be used only in conjunction with Position=Nonlocal in enriched elements:

Select Yes to indicate the normals of pre-existing crack facets in elements are included in the moving least-squares approximation to smooth out the crack normals to obtain the crack propagation direction along the crack front.
Select No to Indicate the normals of pre-existing crack facets in elements are excluded from the moving least-squares approximation to smooth out the crack normals to obtain the crack propagation direction along the crack front..

Select the arrow to the right of the Smoothing field, and it can be used only in conjunction with Position=Nonlocal:

Select None to use the stress/strain at the integration points directly for averaging.
Select Nodal to assemble the stress/strain to element nodes and then interpolate to the integration points for averaging.

Select the arrow to the right of the Npoly field, and is used to specify the number of terms in the polynomial used for the moving least-squares approximation to smooth out the crack normals, only in conjunction with Position=Nonlocal in enriched elements:

Select Least Square to set NPOLY=0 and to suppress the moving least-squares approximation.
Select Linear to set NPOLY=4 and to use a linear polynomial approximation.
Select Quadratic to set NPOLY=7 and to use a quadratic polynomial approximation.
Select Cubic to set NPOLY=10 and to use a cubic polynomial approximation.

Select the arrow to the right of the Weighting Method field, and it can be used only in conjunction with Position=Nonlocal:

Select Uniform to average the stress/strain with a uniform weight function.
Select Gauss to average the stress/strain with a Gaussian weight function.
Select Cubic Spline to average the stress/strain with a cubic spline weight function.
Select User to average the stress/strain with a user-defined weight function.

Enter damage parameters in the Data table:

Maximum Principal Stress or Maximum Principal Strain: Maximum principal stress or strain at damage initiation.
Temp: Temperature, $θ$ .
Field n: Predefined field variables.

You may need to expand the dialog box to see all the columns in the Data table. For detailed information on how to enter data, see Entering tabular data.

Select Suboptions Damage Evolution to define the material degradation that takes place once damage begins.

For more information, see Damage evolution.”

Select Suboptions Damage Stabilization Cohesive to enter the viscous coefficient and improve the model convergence.

For more information, see Damage stabilization.”

Click OK to exit the material editor.