Dear Analysts,

Those of us who are engaged in the simulation of composites have surely encountered situations when the values of Tsai-Hill or Tsai-Wu failure indices calculated by Abaqus are not as expected. The reason for this is that Abaqus uses a failure measure that differs from the failure indices defined by the widely used composites failure theories and implemented in other commercial finite element codes. A new SIMULIA answer titled “Using Failure Criteria for Unidirectional Fiber Composites in Abaqus” attempts to clarify this issue in more detail. Note that the answer is available only to customers with support contracts, but the topic is covered in the Abaqus documentation Ch. 22.2.3, “Plane stress orthotropic failure measures” and the attached PDF file.

The answer also examines Hashin’s failure initiation criteria, which can be used both as postprocessed output and as part of the damage evolution modeling framework, and compares their physical meaning and Abaqus usage with those of the composites failure theories mentioned previously.

Hope you will find this answer valuable.

Vladimir