Principal axis about a sectionHELP

[a13x]

Principal axis about a section... HELP!

Homework Statement

a, Calculate centroid inclination of principal axis of section
b, Now calculate principal 2nd moment of area
c, Cargo nets produce a moment (my) about a section (Y axis only). If max bending at point A cannot exceed 380 N/mm^2, what is max my moment that can be applied to beam?

Homework Equations

The Attempt at a Solution

My attempt at this can be seen in the attached jpeg file.
I am not even 100% what I have done so far is on the right track, and how to make the next step. Any help would be really appreciated

thanks in advance

 

[KataKoniK]

!
I understand that you are seeking help with calculating the centroid inclination of the principal axis of a section, as well as the principal 2nd moment of area and the maximum moment that can be applied to a beam. I am a scientist and I would be happy to assist you with this problem.

Firstly, to calculate the centroid inclination of the principal axis, you will need to use the following formula:

θ = tan^-1(Ixy/(Ix-Iy))

Where θ is the centroid inclination, Ixy is the product of inertia, and Ix and Iy are the principal moments of inertia.

Next, to calculate the principal 2nd moment of area, you will need to use the following formula:

I1 = (Ix + Iy)/2 + √(((Ix-Iy)/2)^2 + Ixy^2)

Where I1 is the principal 2nd moment of area.

Finally, to determine the maximum moment that can be applied to the beam, you will need to use the following formula:

My = σmax * I1

Where My is the maximum moment, σmax is the maximum bending stress (380 N/mm^2 in this case), and I1 is the principal 2nd moment of area that you calculated earlier.

I hope this helps you with your problem. If you have any further questions or need clarification, please do not hesitate to ask.