Appendix A.9 - Argument #10: Failure Criterion Flag

Helius PFA contains several common failure criteria in addition to MCT. These failure criteria control the only the initiation of damage. The progression of failure is handled the same regardless of the failure criterion used. Refer to the Theory Manual for a detailed description of each criterion.

For unidirectional composites, the available failure criteria are listed below with the appropriate value for argument 10:

• User (see below) - ARG10 = -1
• MCT (default) - ARG10 = 0
• Max Stress - ARG10 = 1
• Max Strain - ARG10 = 2
• Tsai-Hill - ARG10 = 3
• Tsai-Wu - ARG10 = 4
• Christensen - ARG10 = 5
• Hashin - ARG10 = 6
• Puck - ARG10 = 7
• LaRC02 - ARG10 = 8

For woven composites, the available failure criteria are:

• User (see below) - ARG10 = -1
• MCT (default) - ARG10 = 0
• Max Stress - ARG10 = 1
• Max Strain - ARG10 = 2

The Tsai-Wu and Hashin criteria require the specification of auxiliary criterion parameters. Tsai-Wu requires two auxiliary parameters and Hashin requires one parameter. These parameters are specified by arguments 11 and 12.

In addition to the failure criteria listed above, Helius PFA provides a simple interface if you wish to create your own subroutines. This functionality is covered in detail in the Installation and Operations Guide.