THEORETICAL METHODOLOGY FOR LIFE ESTIMATION OF DUCTILE NOTCHED MEMBER UNDER CONSTANT AMPLITUDE LOAD IN HIGH CYCLE FATIGUE: A REVIEW

The notch in a structural member acts as discontinuity that gives rise to stress concentration thereby causing the local stress at the notch tip to exceed the far field or applied stress manifold when the member is pressed into service. As the result, the notch tip becomes the most vulnerable zone of the member and therefore the potential site for initiation of monotonic or fatigue failure besides diminishing the fatigue life of the member considerably. The present paper reviews the theoretical methodology to estimate the life of a ductile notched member operating under constant amplitude load in high cycle fatigue (HCF). The member is considered to be isotropic, homogenous and free from internal cracks and material defects. Solution of some examples is presented to demonstrate the procedure for obtaining HCF lives of the members and magnitudes of other design parameters of interest.