Issue 46

V. E. Wildemann et alii, Frattura ed Integrità Strutturale, 46 (2018) 295-305; DOI: 10.3221/IGF-ESIS.46.27 302 Figure 8 : Profiles of the longitudinal strain during uniaxial tension at points 0 4 t t  on the surface of the specimen with embedded defect of 20×20 mm 2 (type 1). Figure 9 : Profiles of the longitudinal strain during uniaxial tension at points 0 t , 1 3 t t   on the surface of the specimen with embedded defect of 20×20 mm 2 (type 1). A similar analysis of inhomogeneous fields of displacements and deformations was made for the specimen with the internal defect of a smaller size (with the material delamination size of 10×10 mm 2 ). Fig. 10 presents the evolution of the longitudinal deformation fields ( ε yy ) and the distribution of z coordinate. The time dependence of the axial load for the specimen with a defect of 20 × 20 mm 2 (Fig. 6) is also characteristic for the specimen with the defect sized 10×10 mm 2 . Evolution of ε yy fields is given for similar points 0 4 t t  . For the specimen with the defect of 10 × 10 mm 2 , the thickening of the specimen in the region of the internal defect is more obvious because of a greater number of delaminations of the composite (Fig. 10). For this configuration of the defect, a smaller degree of inhomogeneity of the longitudinal deformation fields was noted and, as a consequence, a minor effect of the internal defect on the process of deformation and macrofracture of the specimen. In contrast to the specimen with an internal defect of a larger size (20×20 mm 2 ), the localization of longitudinal deformations with a value above the average over the whole specimen was seen in the “delamination” region (Fig. 11). The degree of inhomogeneity of inelastic deformation of the material increases in the process of loading. The analysis of curves in the reloading points ( 0 t and 1 3 t t   ) also revealed no increase of the material delamination in the region of inner defect. C ONCLUSIONS hus, as a result of the mechanical tests under tension and joint tension with torsion, the experimental data on the patterns of inelastic deformation and fracture of the specimens of the layer composite material with prior introduced technological defects that correspond to possible inappropriate compacting and bonding of material layers at a given restricted domain were obtained. T