ABSTRACT
The amount of stress generated by an applied bending moment can easily be calculated from the familiar flexure formula
where
(15)
Inspection of this formula explains why bending should be avoided. Fasteners are typically slender. Therefore, the moment of inertia of a fastener's cross section is rather small. This situation produces a large stress for a given moment. The resulting bending stress must then be added directly to the preload or service load tensile stress in the fastener. Reference 9 contains a thorough treatment of eccentrically loaded joints and their effect on fastener stress. While it is possible to compute the additional tensile stress created by a bending moment, in practice the designer seldom has enough information to complete the calculations. Therefore, the most practical method to account for bending stress in design is to reduce the sources of bending and their severity.
