The Hashin criterion [ 45 ] 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 3D 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 2D and 3D):

(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)