Principal strain failure can be used to represent brittle or ductile failure in materials.
Failure initiation is based on one of two criteria
Maximum principal tensile strain
Maximum shear strain (derived from the maximum difference in the principal strains)
Failure is initiated when either of the above criteria is met. The material instantaneously fails.
If this model is used in conjunction with a plasticity model, it is often recommended to deactivate the maximum shear strain criteria by specifying a large value. In this case the shear response will be treated by the plasticity model.
Note:
The crack softening failure property can be combined with this property to invoke fracture energy based softening.
The combination of principal stress and principal strain failure is supported.
Table 11.18: Input Data
| Name | Symbol | Units | Notes |
|---|---|---|---|
| Maximum Principal Strain | None | User must input a positive value. Default = +1e+20 | |
| Maximum Shear Strain | None | User must input a positive value. Default = +1e+20 |
Custom results variables available for this model:
| Name | Description | Solids | Shells | Beams |
|---|---|---|---|---|
| STATUS | Material Status** | Yes | No | No |
**Material status indicators (1 = elastic, 2 = plastic, 3 = bulk failure, 4= bulk failure, 5 = failed principal direction1, 6 = failed principal direction 2, 7 = failed principal direction 3)