13th International Conference on Fracture June 16–21, 2013, Beijing, China -3- Figure 1. True stress–true strain curves of Al-alloy 6061-T6 and 2024 T351 Figure 2. Analysis model Figure 3. Quarter of finite element mesh with central hole To generate a residual stress field, the applied load must exceed the elastic limit is to say that the force generated during the loading phase of plastic deformation where the isotropic plasticity model of Von Mises was used to account of the plasticity of material. The applied loading and unloading sequence (i.e. 2024 T351 Al-alloy) to generate residual stress by preload is shown in figure 4. The levels of preload is characterized by ratio σp/σy for both materials are shown in Table 2. Figure 5. Loading sequence to generate residual stress 0 100 200 300 400 500 600 0 0,05 0,1 0,15 0,2 True strain True stress (MPa) 0 100 200 300 400 500 0 1 2 3 4 Loading/unloading sequence Applied load (MPa)
RkJQdWJsaXNoZXIy MjM0NDE=