Spectrum(PSD) analysis of composite structures in ANSYS

Hi,

I am trying to perform PSD analysis of a composite structure in ANSYS software. I wonder that  is a failure criteria such as Tsai-Wu available in this analysis type.  In ANSYS Help writes that

"Only component displacement, force, stress, and strain values are 1 σ values and follow a Gaussian or normal distribution. Combined values (e.g. USUM, SI, SEQV, S1, etc.), or component values transformed into another coordinate system are not statistically meaningful, and they should be avoided."(ANSYS Help System//Mechanical APDL // Structural Analysis Guide // 6. Spectrum Analysis // 6.6. Performing a Random Vibration (PSD) Analysis)

Can I use Tsai-Wu in PSD analysis in ANSYS?  If I can't use that, What can I show the failure of composite structures in PSD analysis in ANSYS.

Thanks in advance

Serdar