Multiaxial stress concentration in filleted shafts

In a previous paper, popular stress concentration factor charts for shoulde r filleted shafts in bending and tension H ere shown to be in error, and mo re accurate solutions were published. In this paper, improved stress concen tration factor information is presented for torsional loading, based on det ailed finite element analyses. The new solutions agree with previous design charts, bur cover a wider range of geometries, A concise engineering equat ion is presented for the stress concentration factor and maximum equivalent stress under each of three lending modes, along with another equation that reveals the location of each maximum stress component in the fillet. it is shown that the maximum stress locations for bending and tension loading ar e approximately the same, but can differ significantly from the maximum tor sional stress location. In those cases, sharp surface gradients can cause t he maximum equivalent notch stress under combined bending/axial and torsion al loading to be overestimated when computed based on the maximum stress co ncentration factors for each load component. An example is used to demonstr ate how the surface strain gradient causes the placement and size of a stra in gage to have a strong influence on strain measurements.