LIFTING LUG REPAD
LIFTING LUG REPAD
(OP)
Hello.
We had a problem when compress was showing error to lift the vessel(30,000 lbs) because the shell (3/8" thick)was weak. So we are using repad with lifting lug.
I need the formula to calculate shell thickness required to make sure the shell is good when lifted. Please help. Thank you.
We had a problem when compress was showing error to lift the vessel(30,000 lbs) because the shell (3/8" thick)was weak. So we are using repad with lifting lug.
I need the formula to calculate shell thickness required to make sure the shell is good when lifted. Please help. Thank you.





RE: LIFTING LUG REPAD
There are no formula to find shell thickness while lifting, but u can go for calculation based on external pressure taking the lifting weight(conver it to pressure) as external pressure.
Moreover addition of repads doesnot provide strength to ur vessel.
RE: LIFTING LUG REPAD
RE: LIFTING LUG REPAD
DENNIS MOSS PRESSURE VESSEL DESIGN MANUAL
PAGE 418 and 419
L S THILL
RE: LIFTING LUG REPAD
In reply to ash008 i want to double check if there is no formula to find shell thickness while lifting.
Also according to ash i can go for calcuation based on external pressure- what i understand is that external force is compression force on shell and when lifting using lifting lug it is tensile or outward away from the shell. So if tensile is considered can i just calculate pressure on the repad (P=weight of vessel/Area of pad) and find out thickness required of shell using the formula: P(r)/[S(J.E.)-0.6(P). And if the required thickness is less than actual shell thickness then design is good? Please help. Thank you.
RE: LIFTING LUG REPAD
RE: LIFTING LUG REPAD
If you've never done a rigging/lifting/local stress analysis before, I strongly recommend you seek the help of an experienced vessel engineer. Serious consequences like the loss of lives could happen if your vessel or lugs fail during lift.
ash008,
Wow!!! Where did you get the idea that you can convert lifting weight to external pressure and that repads won't help?
RE: LIFTING LUG REPAD
Ditto to doct9960's comments.
RE: LIFTING LUG REPAD
His book "Mechanical Design of Process Systems", Volume 2, also has a very good chapter on design of lifting devices. This is out of print but may be in many design offices or might be found in a used book store.
RE: LIFTING LUG REPAD