Visualization of Processes of Plastic Deformation Initiation in Conditions of Pure Tension and Pure and Simple Bending

The rules and capabilities of macro-strains identification method with the use of optical interference for identifying initial phase of plastic deformation process in steels with material instability were discussed in the work. It was also shown how the technique run in presentation of the initial phase of yielding progress. As the example for illustration of discussed method real capabilities the course of plastic deformations beginning in the tension tests of 15CrMo and 34CrNiMo6 steel samples was shown as well as the course of test of pure and simple bending for the steel 15CrMo beam. Namely, the sequence of interference fringes pictures showing the formation of plastic strains correlating to the points on the tensile test curve was presented. For bending process the pictures were correlated with the point on the graph of dimensionless bending moment versus maximal strain measured by the strain gauge