Impact of Blade Tip Bending on Blade Design

In an article in Windpower magazine ( … ine-blade/) the following statement was made:

The first objective of most any large wind turbine blade design project is to get to the lightest weight possible.

One predictable outcome of making the blades lighter will be that they will lose stiffness and show more bending at the blade tip (OoPDefl and IPDefl).
In developing a new blade, is there a guidance regarding an acceptable limit for bending at the blade tip? I realize one important consideration would be to assure that the blades do not strike the tower, however I would appreciate a comment regarding what other factors are important. Also, is there a standard means for measuring OoPDefl and IPDefl (e.g., standard deviation)?
Arnold Ramsland

Dear Arnold,

I agree that avoiding a tower strike is the biggest factor limiting blade deflection. A very large blade deflection could also impact the aerodynamic performance and swept area, but the tower strike limit would likely be far more limiting.

I’m not really sure I understand your last question.

Best regards,