#### 5.3.4.4. Hashin Failure Criterion

The Hashin criterion [ 43 ] is used to predict failure in UD (transversal-isotropic orthotropic 23) materials. There are two formulations, one for plane stress and another for the full 3-D stress state.

In the Hashin criterion, criticality of tensile loads in the fiber direction is predicted with the expression:

| (5–54)

Under compressive loads in the fiber direction , failure is predicted with an independent stress condition (for both 2-D and 3-D):

| (5–55)

In the case of tensile transverse stress, the expression for predicting matrix failure is:

| (5–56)

This expression is used when the transverse stress is compressive:

| (5–57)

In addition and optionally, ACP predicts delamination (tension and compression) with this expression:

| (5–58)

The most critical of the failure modes is selected:

| (5–59)

Release 18.2 - © ANSYS, Inc. All rights reserved.