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Ansys Learning Forum › Forums › Discuss Simulation › General Mechanical › Solution combination for Random vibration and Static Structural › Reply To: Solution combination for Random vibration and Static Structural

October 10, 2024 at 5:57 pm
dlooman
Ansys Employee

That wouldn't be correct because the PSD component stresses are unsigned.  That's another issue.  You are adding signed (static) results to unsigned (PSD) results.  The negative static stresses are cancelling out the unsigned psd stresses.  A third issue is that PSD stresses are probabilistic.  The 1 sigma psd stress or less occurs 67% of the time.  The 2 sigma stress 95% of the time, etc...  The static stress is probably determinate and expected 100% of the time.  If the static load is of the same type as the PSD (acceleration), you could add it to the PSD input curve at a low frequency.  The area you add to the curve should be the square of the static acceleration.