Product(s):	SACS
Version(s):	All
Area:	Wind Turbine

Problem (Community Question)

I am trying to carry out a fatigue analysis of an offshore wind monopile structure in SACS using a spectral wave load and damage equivalent wind loads (DEWL) provided from the wind generator turbine manufacturer. I have input these DEWLs in the SACS input file and created a Sea State file with the spectral wave load. What action do I need to follow next?

Solution

The way to combine your DEWL wind fatigue damage with a spectral wave fatigue analysis is to sum the damage of each independent fatigue analysis. In this case you would need to use a deterministic fatigue analysis using the DEWL and a spectral wave fatigue analysis and then combine the damage. The reason for this is that the spectral wave fatigue analysis is a probabilistic analysis which uses the wave spectra to determine the damage which is not associated with any particular wind load. This is fine if you do not expect coupling to occur (i.e. the wind does not affect the wave response), but that is typically not the case for wind turbines. Because of this, wind turbine fatigue design is typically done with a time-history approach. The wind response is combined with the wave response into a single time-history which can then be used to determine the fatigue damage. Our Wind Turbine utilities in SACS are intended to be used for these types of analyses.

Fatigue analysis using damage equivalent load

Problem (Community Question)

Solution

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