damage equivalent load

Wind & Water Computer-Aided Engineering Software Tools
1

I want to compare two tower base loads achieved from two control strategies as below:

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What is the best and easiest way to compare them?
Should I compute damage equivalent load of both cases to compare them? If yes, how to compute?

Excuse if my question is incipient.

2

Dear Mehdi,

My guess is the “best method” likely depends on your own needs. Certainly, there is some historical precedent for comparing the influence of different controls strategies through the comparison of damage-equivalent loads (DELs). NREL post-processors MCrunch and/or MLife can compute DELs from time series.

Best regards,

3

Thanks Jason,
I downloaded the Mlife and run it with Matlab, but looking at Mlife, it has many options to compare the outputs of several simulations that dazzles me as I am beginner at it.
I only want to compute 2 damage equivalent loads for two simulations, Is there anyone that could tell briefly how to do it with Mlife?

4

Dear Mehdi,

You might want to look at the certification tests under the CertTest folder of the MLife distribution. Test02.mlif and Test05.mlif both generate short-term DELs. If you examine the MLife_User.pdf, located in the documentation folder, you will be able to interpret the various parameters. The DEL calculation theory is can be found in the MLife_Theory.pdf document. If, at that point, you have specific questions regarding one or more of the MLife parameters, I’d be happy to try and answer them.

Best Regards,

Greg Hayman

5

Hello,
I have gone through the MLife (theory and user) manuals. From what i understood, I don’t see damage equivalent load (DEL) providing any extra information than the ‘damage’ calculation.
I am aware that in the literature DEL is used as a metric to compare different controller designs.
I find DEL more difficult to interpret than ‘damage’. Also, the DEL calculation anyways require ‘damage’ calculation. This raises the question, why bother calculating DEL? Am I missing something?

Regards,
Kumara

6

Dear @KumaraRaja.Eedara,

The DEL can often be interpreted more easily because it has the same units and similar magnitude as the load under consideration. The damage itself is unitless and typically a very small fraction of unity.

Best regards,