Thanks for the info. Thanks for the offer on the mathcad program, but I don't have matchcad (or even a fortran compiler, if it kicks it could be kicked out as code.) Besides, it needs to be in a documented report, so I will have to go through the calc from scratch anyway. Thanks though.
I'm doing a stress analysis (hand calcs, not FEA) on some round air ducts. Someone brought up the stress at flanges (either into air boxes or expansion joints) could be a concern. I guess I can imagine how a stiff section of the flange might cause some localized stress, but I don't know how to...
