OpenFAST
WT structural loads an pitch control.
Hello everyone I do not know if this is the right place for this question, but this doubt originated from a OpenFAST signal analysis.
I'm doing a pitch controller using OpenFAST simulation; the pitch controller is optimized to improve power regulation. However, regarding the structural loads... I can't find detailed information on what loads I should analyze.
I've seen works mention thrust at the hub center, the blade flapwise/edgewise root bending moment, and the tower bottom fore aft/side-to-side bending moment. But they do not provide any further justification; rather, they are considered the most affected by pitch control.
Do you have any guidance to:
- Which are the structural loads considered most affected by pitch control.
- Does it really need a strong justification, or it is just determined by experience?
Dear @vicemora,
If you are not applying OpenFAST to design/redesign the structural components, but rather, applying OpenFAST to analyze the effect of a controller change on structural loads, it is common to use a few component loads as representative of the impact, such as the blade root and tower base bending moments as you outlined. If you want more representation, you could use other loads in the blade (such as 50% span), other loads in the tower (such as 50% height and tower-top), also include tower-top yawing moment, blade-root pitching moment, and drivetrain-bending loads at the main bearing.
Best regards,
@jjonkman Thank you for the advice. Is there any document where that fact is stated? That is what reviewers of an article ask me to do. I've included the blade root edgewise moment, but pitch control seems not to affect it, and the reviewers ask me to analyze why... Do you have any document that can help? or... is this something like "word of mouth"?
Dear @vicemora,
My comment was simply a summary of what I've seen in the literature.
Blade-edgewise bending is dominated by gravitation loading of the blades, and so, may not be too sensitive to pitch control; blade-flapwise bending should be more sensitive.
Best regards,
Thank you @jjonkman!! Last, any insight about the tower side-to-side bending moment's affectation in pitch control?
Dear @vicemora,
I'm not sure I fully understand your question. Tower side-side bending is more directly influenced by the torque controller, but pitch control could have a minor effect.
Best regards,