What is stress concentration ? State the remedial measures to control the effect of stress concentration with neat sketches

i. Stress Concentration: Whenever a machine component changes the shape of its cross-section, the simple stress distribution no longer holds good and the neighborhood of the discontinuity is different. This irregularity in the stress distribution caused by abrupt changes of form is called stress concentration. It occurs for all kinds of stresses in the presence of fillets, notches, holes, keyways, splines, surface roughness or scratches etc.

The presence of stresses concentration cannot be totally eliminated but it can be reduced, so following are the remedial measures to control the effects of stress concentration. 1. Provide additional notches and holes in tension members as shown in fig (a) a)Use of multiple notches. b)Drilling additional holes as shown in fig(b) 2. Fillet radius, undercutting and notch for member in bending. 3. Reduction of stress concentration in threaded members as shown in fig(c) 4. Provide taper cross-section to the sharp corner of member as shown in fig(d)