Issue 46

V. E. Wildemann et alii, Frattura ed Integrità Strutturale, 46 (2018) 295-305; DOI: 10.3221/IGF-ESIS.46.27 299 (a) (b) Figure 3 : Temperature fields on specimen surface with different type of laying defects: (a) type 1, (b) type 2. (a) (b) Figure 4 : The ' P u  ’ (a) and ‘ M   ’ (b) curves obtained in tension-torsion test of specimen without defects ( 0.028 k  ). Tension with torsion testing of specimen with embedded defects In order to experimentally study the mechanisms of inelastic deformation and fracture of specimens of carbon fiber with internal defects under complex stress state, mechanical tests are performed with the proportional tension with torsion with the ratio 0.028 k  . To evaluate the development of the internal defect, tests were carried out with three reloadings and repeated loadings. The reloading was performed until the level of the axial load was 10 P  kN. In the case of the internal defect formation under loading, a possible change of the images of deformation fields at the time of reloading is assumed. Comparison of the configuration of the longitudinal deformation fields during reloading will allow to estimate the increase in the region of delamination of the composite material. Fig. 5 shows loading diagrams in the “load-displacement” and “torque-torsion angle” coordinates obtained by the tension- torsion of specimens with internal defects sized 20×20 mm 2 and 10×10 mm 2 . The diagrams are also built based on the data of the built-in sensor of the test system.