Unit Check for lifting lug or structures

[jtseng123]

Dear all,

A lifting lug or structures will have tensile stress, bending stress and shear stress happening at the same location.

Does Unit Check include shear stress, such that St/Sta + Sb/Sba + Ss/Ssa <=1.0 ?

If no need to include, why ? I think Unit Check is another way to simplify Mohr's Circle, then shear shall be included in the unit check, even it is perpendicular to the other two stresses.

 

[ColinPearson]

You'll want to look at an applicable code. ASME BTH-1 (current version is 2014) would be the typical go-to in the US, but there's a lot involved. I myself have done this type of design a number of times and still have questions that I've been trying to work through on this site as well as directly with ASME.

KootK and TehMighty were very helpful the other day with some of my questions; you would do well to look at some of their responses.

I'd also direct you to two articles by Tim Duerr. He's something of a towering figure in the lifting/rigging world and a hell of a nice guy to boot.

See Duerr:
"ASME BTH-1 Pinned Connection Design Provisions", 2008
"Pinned Connection Strength and Behavior", 2006

You may also ferret out an article called "Design of Lifting & Tailing Lugs", (not sure who this is by) and David T. Ricker, "Design and Construction of Lifting Beams", 1991.

Your OP says "lifting lug or structures", so if it's a structure and not a lug as I presumed, there will be some steel design code applicable wherever you may live.