Tsai-Wu Failure Criterion
Failure Criterion
The Tsai-Wu criterion is applied to composite shells.
This criterion considers the total strain energy (both distortion energy
and dilatation energy) for predicting failure. It is more general than
the Tsai-Hill failure criterion because it distinguishes between compressive
and tensile failure strengths. For a 2D state of plane stress (s3 =0,
t13 =0, t23 =0) that is assumed for the composite
shells, the failure index is computed as:
The program reports the factor of safety (FOS)
as 1 / (F.I.). The FOS should be greater than 1 for laminates to be safe.
where
X1 is the tensile strength in material
direction 1
X2 is the tensile strength in material
direction 2
S12
is the shear strength
Superscripts T
and C denote tensile and compressive
strengths respectively.
Click principal material directions
for a definition of material directions 1 and 2.
Limitation
The Tsai-Wu failure criterion cannot predict different failure modes
including fiber failure, matrix failure, and fiber-matrix interface failure.
Related Topics
Performing factor of safety check
Guidelines
for Selecting a Failure Criterion
Composite
Failure Criteria