Hello everybody,

I am peeking at the code of WISDEM to try to implement blade load calculations in case of storm, and now I am dealing with the outputs of rotor_structure::RunFrame3DD, i.e., *wt.rotorse.rs.frame.(F2, F3, M1, M2)*.

Below is the trend of F2 vs the blade span that I get with the data from the .csv file of a successful optimization made with the standard version of WISDEM (not the one I am modifying):

Now, in my understanding, F2 is mainly the shear force on each blade section, so I was expecting the graph to show the maximum at the blade root, but the F2 load peaks at ~30 m and then decreases towards the blade root.

I checked the code and found the line of RunFrame3DD that computes F2 commented as below (I am using WISDEM 3.10.1):

```
# shear and bending w.r.t. principal axes
F2 = np.r_[-forces.Vz[iCase, 0], forces.Vz[iCase, 1::2]] # TODO verify if this is correct
F3 = np.r_[-forces.Nx[iCase, 0], forces.Nx[iCase, 1::2]]
M1 = np.r_[-forces.Myy[iCase, 0], forces.Myy[iCase, 1::2]]
M2 = np.r_[-forces.Mzz[iCase, 0], forces.Mzz[iCase, 1::2]]
```

So, can someone explain me whether there is a problem with RunFrame3DD outputs, or I was expecting the wrong trend?

Thank you for your time and attention,

Henny