Beginning of plastic yielding in a stress concentration zone

See preceding abstract. Using as an example a problem involving the stretching of a plate with elliptical holes, the limits of applicability of the gradient criterion and a model of complex media with very small holes, a connection was noted between this criterion and the material structure. It is shown that over a fairly wide range of stress concentration coefficients and hole sizes this criterion virtually reflects the energy principle governing the commencement of plastic flow. Aluminum alloys D19AT, V95 and steel St3 are included in the analysis.