Hey Y'all! Looking for a little guidance on designing lifting lugs here. I do this routinely and the lug calcs (by hand) are no problem for me. That said, I'm not a vessel guy, so the local stress on vessels is a bit outside of my wheelhouse. In this case, the client has indicated they have significant, known corrosion issues in the existing vessel.

What I'd like to do is run lug calcs in COMPRESS as if the corrosion had already reduced the vessel wall thickness. However, I want the full weight of the vessel to be used in the calcs to check everything b/c obviously I can't know the true extent of corrosion.

My thought was to "fake" it by using a wall thickness equal to the original minus the corrosion that the client has told us to expect. Then I would take the difference in weight between the original and corroded conditions and apply that as a liner with the density manipulated to make up that difference. If I'm thinking right, that would run the local stress calcs on the thin metal but the lugs would be loaded with the original/uncorroded weight. However, COMPRESS appears to force me to use a min thickness that is greater than what the approx corroded thickness is.

What do y'all think about that, sound reasonable?

Thanks for your help, have a great day and stay safe!