Lifting Beam calculations

[cjme]

Hey everyone,

I'm trying to design a lifting beam that is going to lift 2 objects side by side. The smaller object is about 8 feet long & weighs 2200 lbs, and the larger object is about 22 feet long & weighs 36000 lbs. We are using a single lifting point over the center of gravity, and are trying to use something that looks similar to a modified "J" shape
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That's my attempt at a diagram, I know it's hard to follow. The long object has 2 I-beams running down the length, the small object has 1 beam running the length, and then there are 2 beams connecting the two together. The beams have big J-hooks on each side of them, which they'll slip cable slings over to pick up the objects.

I know my attempt at the explanation kind of sucks, but can someone help me with the calculations & analysis so I can see if what I've done will be strong enough? I tried running some FEA but it killed my computer, and I'm only 5 months out of school so I'm used to neat textbook solutions, not these crazy real world problems. Thanks.

 

[zekeman]

This is NOT a "real world problem". Nobody in his right mind would ever use this type of lifting mechanism. You will kill somebody with it. Must have been designed by a Physics PHD type.
That is probably why you got no response.

 

[rb1957]

don't see why this'd "kill your computer".

the only reason i can see to have I-beams running the length of the slung things (lets call them thing1 and thing2) is because they are supported by the I-beams along their length (rather than attached at their ends).

maybe thing1 and thing2 aren't able to support their own weight, so you've lashed them to the I-beams.

i suspect zekeman's point is that you probably won't want to design a fixed point of support ('cause this doesn't allow for any variation). supporting the sling point on a bunch of cables, so it can easily adopt the CG location, probably makes more sense.

this isn't my field, but maybe you could use a set of turnbuckles, cables with length abjustment in them. maybe this is too "fussy" for your application.

 

[arto]

for good lifting info, look at:
MIL-STD-209J
ASME B30

http://www.eh.doe.gov/techstds/standard/std1090-04/toc.html

Confucius said that knowledge is "When you know a thing, to recognize that you know it, and when you do not know a thing, to recocognize that you do not know it. That is knowledge."

so.....when you realize it's time to call the pro's:

http://www.zinterhandling.com/

http://www.bushman.com/

http://www.tandemloc.com/index.asp

http://www.lift-all.com/