Stress Intensity Factor (K)

Definition - What does Stress Intensity Factor (K) mean?

The stress intensity factor (K) is used in the field of fracture mechanics. It predicts stress intensity near the tip of a crack caused by a remote load or residual stresses.

The magnitude of K depends on:

  • Sample geometry
  • Size and location of the crack
  • Magnitude of load
  • Distribution of load

The stress intensity factor is a single-parameter characterization of the crack tip stress field.

Corrosionpedia explains Stress Intensity Factor (K)

The following equation describes stress intensity:

Where ß describes the relationship between gross geometrical features to the stress intensity factors. ß can be a function of crack length as well as other geometrical features. K represents nominal stress that is remote from the crack.

The above equation shows that the intensity of the stress field — and therefore the stresses in the crack tip region — are linearly proportional to remotely applied stress and proportional to the square root of half the crack's length.

Stress intensity can be determined by:

  • Finite element analysis
  • ASTM E1681 standard method
  • Weight function method
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