Unit Check for lifting lug or structures
Unit Check for lifting lug or structures
(OP)
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.
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.





RE: Unit Check for lifting lug or structures
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.