A study of cyclic plastic stresses at a notch root

An experimental study is presented for cyclic plastic stresses at notch roots in specimens under constant-amplitude repeated tension and reversed loading. Edge-notched,KT=2, 2024-T3 aluminum-alloy sheet specimens were cycled until local stress conditions stabilized. Local stress histories were determined by recording local strain histories during cycling and reproducting these histories in simple, unnotched specimens. The fatigue lives for these notched specimens were estimated using stabilized local stresses and an alternating vs. mean stress diagram for unnotched specimens of the same material. These predictions compared favorably with lives from S-N data for the notch configuration tested.In addition, an expression is presented for calculating local first-cycle plastic stresses. An acceptable correlation is shown between predicted stresses and experimental data within the scope of the investigation.