Issue 43

M.P. Tretyakov et alii, Frattura ed Integrità Strutturale, 43 (2018) 146-154; DOI: 10.3221/IGF-ESIS.43.11 148 Figure 1 : Installation of equipment for carrying out tension tests under combined using of biaxial test system Instron 8850 and 3D digital video system for analyzing of displacement and strain fields Vic-3D Correlated Solutions T EST RESULTS he approach used in the work is called "specimen from specimen", described earlier in [1, 7, 27]. For tensile tests, standard solid cylindrical specimens with a nominal diameter of the test part of 8 mm and with a length of 40 mm  0 0 ( / 5) l d were made. The specimens were stretched to achieve different strain levels at the postcritical deformation stage, which was followed by necking effect. After achieving necessary levels of deformation, the samples were unloaded. There were done three different levels of deformation, achieved to the beginning of unloading, which parameters are presented in the Tab. 2, which contains the strain values ε, stresses σ and corresponding values of the coefficient of realization of the postcritical deformation stage       1 / 1 / P P B P B k P P , possessing the following values of   0 1. P k Figure 2 : Strain curves ( a ) of steel 40Cr under tension up to failure (solid line) and tension curves up to various levels of postcritical deformation and unloadings (dashed lines); pictures of the test part of specimens with neck at different levels ( b ) . T