Issue 27

T.V. Tretiakova et alii, Frattura ed Integrità Strutturale, 27 (2014) 83-97 ; DOI: 10.3221/IGF-ESIS.27.10 86 Figure 3 : The load-displacement curve of the uniaxial tension of the dog-bone Al-Mg specimen. Elastic Deformation Stage To estimate the kinematics and irregularity of plastic flow during uniaxial tensile tests of Al-Mg alloy sheet, the axial strain fields ( yy  ) and the strain rate fields ( yy   ) have been determined on the specimens surfaces. Fig. 4 contains the singled out elasto-plastic deformation stage of the P–u curve (Fig. 3) for the detailed description of the material behavior, especially during the Lüders band nucleation. Consequently, the stage of yield drop and yield plateau forming is under observation. Figure 4 : The initial stage of the load-displacement curve of the uniaxial tension of the dog-bone Al-Mg specimen. At the initial stage, the process of material’s deformation was running uniformly up to the upper yield point ( В Т  ) or the yield drop (point I, Fig. 4). Fig. 5 presents the axial strain fields on the specimen’s surface for the load level of 2.45 kN. For visualization of the deformation field configuration, the two-dimensional and three-dimensional ( , , yy x y  ) representations are reported. It can be clearly seen that the mean value of the axial strain is fixed on the level of 0.18 %.