Thin body Fea analysis for vessel

[Anonymous]

A vessel model was created to design a tail lifting lug for the rigging,  this model was created as a solid and included weldings between the pipe support only gravity was added as load and I restrain both the top ear lugs and the tail lug but when I run the FEA analysis there is a warning indicating that some thin bodies are treated as a solid. However the results are within the maxing allowables. If I take the same model and create automatically the thin bodies as suggested by the previous warning and run the Analysis again the results are to different, the stress appears in weldings that has no load like the opposite leg to the one which has the tail lug (I will add some snapshots). My question is why is this happening?  Is the first analysis without thin bodies reliable?  I appreciate your comments, thanks regards from Colombia.

[blair]

Check the material for the "thin body", someone else had an issue with "thin bodies" having the material reverting to "generic".

[Anonymous]

Morning Blair, thanks for your reply, I had used carbon steel at the begining but modified the yeild and ultimate streght in this simulation according to the real materials, when I click on the materials tab in simulations seems like the material is still according with my modifications (see attachment), I do not know what else can be wrong, if you want to check the whole model I could upload the pieces and assembly, thanks one more time, hope you can give me another hint with this mess.

[blair]

If you want to pack-and-go the assembly, zip it and e-mail it to me I can run it through mine as well as Simulation Mechanical: email address is: blair dot stunder at arcticmfg dot com

[Anonymous]

I would like to add some extra information about the performed thin body analysis, there are some other warnings that inventor pops up (see atachment):

1.the model is divided in two indepent components.

2. it has been added a no proportinal variation spring.

I am not sure what this warnings could mean exactly but once you see the results it seems like the contacts or something like that is failing badly becouse the displacement in the lower part of the model are really high compared with the same obtained with the solid model, just look where the manhole ends in the snapshoot. 

also the lower part of the thin body model gets the higher stress but it should be backwards the most stressed part should be the upper one with the restriction.

I know the thin body model is the most suitable way to represent slim plates like the shell of my vessel becouse the solid body model could be so stiff and the bending stresses could not be represented in a reliable way but honestly I do not know what else to do,

I try to perform this analysis to confirm the design and placement of a rigging tail lug and its welding to the vessel, so my main question is still: Should I trust in the solid body analysis and its results?

I hope someone can help me, regards.

[blair]

Looks like you have some issues with the lower "leg" or bracket. Try increasing the boundary gap. This should then include this item as part of the main body.