Elasto-plastic stress and strain behaviour at notch roots under monotonic and cyclic loadings

Notch deformation behaviour under monotonic and cyclic loading conditions was investigated using circumferentially notched round bar and double-notched flat plate geometries, each with two different notch concentration factors. Notch strains for the double-notched plate geometry were measured with the use of miniature strain gauges bonded to specimens made of a vanadium-based microalloyed steel. Elastic as well as elasto-plastic finite element analyses of the two geometries were performed. Notch root strains and stresses were predicted by employing the linear rule, Neuber’s rule and Glinka’s rule relationships under both monotonic and cyclic loading conditions. The predicted results are compared with those from elastic–plastic finite element analyses and strain gauge measurements. Effects of notch constraint and the material stress–strain curve on the notch root stress and strain predictions are also discussed.