To me, "rigging analysis" considers the stresses in the vessel cross-section as distributed along its length from top to bottom. At one time COMPRESS included this sort of analysis. It was a relatively reliable function but could be fooled by some unusual types of vessel geometry. It was removed from COMPRESS at the time that the options for design of lifting lugs and tailing lugs was added to the program (about 2 years ago).
The lifting lugs and tailing lugs (and now lifting trunnions) consider stress in the lugs themselves and the local stresses in the shell at the lug under various lifting conditions and angles. But no consideration is given to stresses in the shell gross cross-section at other locations along the vessel axis. eg: In some cases it may be necessary to check the vessel at its midspan between the lifting points, or to check a thin skirt where it attaches to the vessel.
We plan to add the full rigging analysis back to COMPRESS in a more robust version.
Thank you very much Tom. That was quite helpful.
On that let me add another question, if I understand correctly,
Compress will tell me if the lifting/tailing lug/trunion and the shell where they are located based on the input parameters is overstressed (or not), which effectively means, that the design is insufficient. So my question now is, does Compress also suggest (or perform) lug/trunion design based on calculations?
