Stresses at keyway ends near shoulders

Abstract

The photoelastic stress analysis of a series of shouldered shafts with keyways in the shanks is described. Direct loading and torsion have been studied. The shoulder-fillet ratio (shoulder-fillet radius/shank diameter) and the distance between keyway end and shoulder have been varied but both the ratio of the shoulder diameter to the shank diameter and the ratio of the keyway-fillet radius to the shank diameter were held constant through the model series. It is shown for both forms of loading that variations in the shoulder-fillet ratio have no significant effect on the greater principal stresses in the keyway fillet when the keyway end touches the shoulder-fillet toe; appreciable changes are caused in the stresses at the top of the keyway wall for torsional loading. Shoulder-fillet stresses are also presented. The dependence of the keyway stresses on the distance between shoulder fillet and keyway end has been studied; important stress reductions occur when the keyway end is continued through the shoulder fillet and into the shoulder proper. Maximum-stress indices for combined direct and torsional loads are derived for a particular geometry.