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Glossary

Stress Concentration Factor (K_t)

Stress concentrations arise from any abrupt change in the geometry of a part under load. As a result, the stress distribution is not uniform throughout the cross-section.

For example, is often necessary to drill a hole in a plate. When a load, P, is applied, the presence of the hole disturbs the uniform nominal stress in the plate.

The profile of the stress in the cross-section through the center of the hole has the form shown in bottom of the figure. Notice that the maximum stress, σ_max, is 3σ and occurs at the edge of the hole. The factor of 3 is known as the stress concentration factor, K_t. It can be seen from the figure that any stress values larger than σ are localized in a region with a diameter approximately equal to D.