Question

An axial residual compressive stress due to a manufacturing process is present on outer surface of a rotating shaft subjected to bending under a given bending load the fatigue life of a shaft in the presence of the residual compressive stress is

Answer 1

In the presence of the residual the compressive stress increases.

• The fatigue life of a bent spinning shaft will always be extended under residual axial compressive stress as it decreases the tensile stress on the fiber in one revolution and raises the compressive stress on the same fiber during the half revolution.
• From the Parabola of the Gerber which is the typical curve of the shaft's fatigue life in the face of residual compressive stress. The material's fatigue life is efficiently improved by applying a compressive mean force, whether current or residual.