In Figure 9-6 a representative single-shear joint is shown, with centrally applied loads ( P) in each lug, and bending moments ( M and M 1) that keep the system in equilibrium. The new increased value of pin ultimate bending load is

The portions of the lugs and bushings not included in b 1 and 2b 2 are considered ineffective. These shifted loads are assumed to be uniformly distributed over widths b 1 and 2b 2, which are less than t 1 and t 2, respectively, as shown in Figure 9-5. of the bearing loads toward the shear faces of the lugs, resulting in a decreased pin bending moment and an increased value of P ub.P. However, such a pin may deflect sufficiently under load to shift the c.g. If P ub.P (Equation (9-15)) is less than both P u.L.B (Equation (9-11)) and P us.P (Equation (9-12)), the pin is considered a relatively weak pin, critical in bending. The allowable load for the joint ( P all) can be determined by going directly to Equation (9-19a). If P ub.P is equal to or greater than either P u.L.B (Equation (9-11)) or P us.P (Equation (9-12)), then the pin is a relatively strong pin that is not critical in bending, and no further pin bending calculations are required. In addition, the lug and bushing must be checked to ensure that the deformations at design yield load are not excessive. The net-section of the lug through the pin must be checked against net-tension failure. The bearing strength of a lug loaded in tension, as shown in Figure 9-1, depends largely on the interaction between bearing, shear-out, and hoop-tension stresses in the part of the lug ahead of the pin.

'Balanced design' pin ultimate bending loadĪllowable bushing transverse ulti.Inate loadĭistance from edge of hole to edge of lug, inchesĭuctility factor for lugs with less than 5% elongationĮdge distances in transversely loaded lug, inchesĮffective edge distance in transversely loaded lugĪngle of load to axial direction, degreesĩ.3 Lug and Bushing Strength Under Uniform Axial LoadĪxially loaded lugs in tension must be checked for bearing strength and for net-section strength. Ultimate shear stress of the pin material Cross grain tensile ultimate stress of lug materialĬross grain tensile yield stress of lug materialĪllowable lug net-section tensile ultimate stressĪllowable lug net-section tensile yield stressĪllowable bearing yield stress for bushingsĪllowable bearing ultimate stress for bushings

Lifting lug calculation pdf