Padeye

The following check should be done for the design of padeyes and to keep the stress less than the allowable stresses:

At the hole:

1. Bearing stress
2. Shear stress
3. Tensile stress
4. Hertz bearing stress

At the base

1. Shear stress
2. Tensile stress
3. Bending stress
4. Combined bending stress and tensile stress
5. Von-Mises stress^[1]

Analysis on a padeye is commonly performed in accordance with the Air Force Stress Analysis Manual^[2] or ASME BTH-1.^[3] The methodology in ASME BTH-1 only allows for axially loaded lugs, whereas the methodology in the Air Force Stress Analysis Manual allows for axial loading, transverse loading, or oblique (combined) loading.^[4]

Tests have confirmed that there are four potential failure modes for a lug plate:

1. Tension failure at the sides of the hole
2. Crushing above the lifting pin followed by tearing tension fracture at the plate edge
3. Shear failure in the lug plate as the lifting pin attempts to plow its way towards the edge of the free plate
4. Dishing (out-of-plane buckling) failure of relatively thin lug plates that are laterally unrestrained