1. 22565 EMD : 1.4 : Fundamental of Design
Stress Concentration
Definition : It is the irregularity in the stress distribution
caused by abrupt changes of form or shape is called
stress concentration.
Stress Concentration factor
It is defined as the ratio of the maximum stress in a
member (at a notch or a fillet) to the nominal stress at
the same section based upon net area.
Kt = Maximum stress / Nominal stress
2. 22565 EMD : 1.4 : Fundamental of Design
Causes of Stress Concentrations
1) Abrupt or sudden change in cross section
e.g. Keyways, steps, grooves
2) Poor surface finish
e.g. Rough surface, knurl surface
3) Localized loading
e.g. Ball and race, cam & follower
4) Variation in material properties
e.g. different material welding, joining
5) Material defects
e.g. cracks, flaws, air holes, cavities
3. 22565 EMD : 1.4 : Fundamental of Design
Remedies for reduce the Stress Concentrations
1) Abrupt or sudden change in cross section
2) Avoid rough surface
3) Avoid pointed localized loading
4) Select proper and uniform material
5) Reduce cracks, flaws, air holes, cavities
