Damage accumulation in stress concentration zones of parts with hardened surface under low cycle tension-compression and bending

This paper provides experimental and analytical evaluation of durability of nonhardened and hardened by EMT specimens of grade 45 steel with stress concentrators, under low cycle tension-compression and pure bending. For both type of loading modes was carried out durability analysis, taking into account fatigue and quasi-static damage depending on loading level and number of s. Stress and strain concentration coefficients were calculated by analytical and finite element methods (FEM) under elastic plastic cyclic loading. Performed analytical investigation showed, that suggested method for quasi-static and fatigue damage summation, when accumulated plastic strain and the width of the hysteresis loop are taken into account, provides a very good agreement with the experimental results at stress concentration zones of surface-hardened pans under tension-compression and bending.