Products: ABAQUS/Standard ABAQUS/CAE
The material damage initiation capability for fiber-reinforced materials:
requires that the behavior of the undamaged material is linearly elastic (see Linear elastic behavior, Section 17.2.1);
is based on Hashin's theory (Hashin and Rotem, 1973, and Hashin, 1980);
takes into account four different failure modes: fiber tension, fiber compression, matrix tension, and matrix compression; and
can be used in combination with the damage evolution model described in Damage evolution and element removal for fiber-reinforced composites, Section 19.3.3 (see Failure of blunt notched fiber metal laminates, Section 1.4.6 of the ABAQUS Example Problems Manual).
Damage initiation refers to the onset of degradation at a material point. In ABAQUS the damage initiation criteria for fiber reinforced composites are based on Hashin's theory (see Hashin and Rotem, 1973, and Hashin, 1980). These criteria consider four different damage initiation mechanisms: fiber tension, fiber compression, matrix tension, and matrix compression.
The initiation criteria have the following general forms:
Fiber tension :
Fiber compression :
Matrix tension :
Matrix compression :
denotes tensile strength in the fiber direction;
denotes compressive strength in the fiber direction;
denotes tensile strength in the direction perpendicular to the fibers;
denotes compressive strength in the direction perpendicular to the fibers;
denotes the longitudinal shear strength;
denotes the transverse shear strength;
is a coefficient that determines the contribution of the shear stress to the fiber tensile initiation criterion; and
are components of the effective stress tensor, , that is used to evaluate the initiation criteria and which is computed from:
Prior to any damage initiation and evolution the damage operator, , is equal to the identity matrix, so . Once damage initiation and evolution has occurred for at least one mode, the damage operator becomes significant in the criteria for damage initiation of other modes (see Damage evolution and element removal for fiber-reinforced composites, Section 19.3.3, for discussion of damage evolution). The effective stress, , is intended to represent the stress acting over the damaged area that effectively resists the internal forces.
The initiation criteria presented above can be specialized to obtain the model proposed in Hashin and Rotem (1973) by setting and or the model proposed in Hashin (1980) by setting .
An output variable is associated with each initiation criterion (fiber tension, fiber compression, matrix tension, matrix compression) to indicate whether the criterion has been met. A value of 1.0 or higher indicates that the initiation criterion has been met (see “Output” for further details). If you define a damage initiation model without defining an associated evolution law, the initiation criteria will affect only output. Thus, you can use these criteria to evaluate the propensity of the material to undergo damage without modeling the damage process.
Input File Usage: | Use the following option to define the Hashin damage initiation criterion: |
*DAMAGE INITIATION, CRITERION=HASHIN, ALPHA= , , , , , |
ABAQUS/CAE Usage: | Property module: material editor: MechanicalDamage for Fiber-Reinforced CompositesHashin Damage |
The damage initiation criteria must be used with elements with a plane stress formulation, which include plane stress, shell, continuum shell, and membrane elements.
In addition to the standard output identifiers available in ABAQUS (ABAQUS/Standard output variable identifiers, Section 4.2.1), the following variables relate specifically to damage initiation at a material point in the fiber-reinforced composite damage model:
DMICRT | All damage initiation criteria components. |
HSNFTCRT | Fiber tensile initiation criterion. |
HSNFCCRT | Fiber compressive initiation criterion. |
HSNMTCRT | Matrix tensile initiation criterion. |
HSNMCCRT | Matrix compressive initiation criterion. |