Stress Concentrations: Their Effect on Design for Repeated Loading

Changes of section, such as fillets, grooves, oil holes, keyways, and the like, are necessary in many machine parts. These are sources of stress concentration when a part is under load, Stress concentrations may also occur near bolts, pins, rivets, spot welds, and other discrete fasteners in joints of structural members. Flaws, inclu-sions, and other discontinuities in a metal may also interrupt the stress pattern under load. The general term "stress raiser" has been coined to describe any such irregularity or inhomogeneity which produces it local concentration of stress in a loaded part.