Torsion on materials of variable cross section

LessthanSane

New here, sorry if I'm in the wrong place or unclear, etc.

I've been looking at torsion on solid plates and the torsion constant. I was wondering how to handle the torsion constant on a plate of changing cross section (e.g. there are holes drilled in it, changing the area of the cross section and shape, leaving it without a uniform solidity) without doing an FEA (I might have access to something like solidworks simulation stuff in the future, but not at the moment).

Originally, I thought maybe too integrate along the length for the changing area, but that doesn't account for the shape.

Can anyone help me? Sorry if this is a dumb question.

nvn

I do not know if this would help you a little, but just in case. Post 3781736 (post 3) was made on the day after your post.