Issue 39

O. Daghfas et alii, Frattura ed Integrità Strutturale, 39 (2017) 263-273; DOI: 10.3221/IGF-ESIS.39.24 271 Using the identified anisotropic coefficients (Tab. 2), the behavior model allows to represent the load surfaces on each test (simple tensile ST for 3    , simple shear SS for 2    , wide tensile WT for 6    ) in the deviatory plan [16, 19], where D D x x 2 3 sin cos 2 sin sin 2             (8) Fig. 7 shows the comparison between the yield surfaces calculated by behavior model on different tests. Figure 6 : Validation of hardening tensile curve at 90    . Figure 7 : Evolution of the load surface in the deviatory plan   x x 2 3 , . It appears also that this material is resistant to simple shear much more than simple tensile and wide tensile. Furthermore, for simple tensile and simple shear tests the 7075-T7 alloy is plasticized quickly along the 45° direction from the rolling direction. It is deduced that the best shaping in the design of the fuselage is realized using the 7075 alloy in the 45° direction. In contrast, in wide tensile, it is achieved at the same time at three loading directions. C ONCLUSION ince the commercial 7075 aluminum alloys are essentially aeronautics alloys, off - axis tensile tests are carried on 7075aluminum alloy through three loading directions from the rolling direction. These experimental results have allowed to investigate the mechanical properties and to identify the plastic behavior model using a proposed S