Issue 50

M.F. Borges et al., Frattura ed Integrità Strutturale, 50 (2019) 9-19; DOI: 10.3221/IGF-ESIS.50.02 14 Figure 4 : (a)Plastic CTOD range, δ p , versus the variation of the yield stress relative to the reference value in percentage, (plane stress; No contact). Figure 5: (a) Stress-strain curves for the reference value of the yield stress and 1.25 times that value (b) Schematic representation of Gauss point, at a distance of 1.184 mm ahead of the initial crack tip position, and crack growth (SS304L; plane stress; no contact). Figs. 6a and 6b plot load above onset of plastic deformation versus CTODp for SS304L and AA7050, respectively, in plane stress conditions. The objective is to study the material hardening at the crack tip, as a function of the yield stress. Further increases in load are required to increase the plastic CTOD. Also, the rate of variation of plastic CTOD increases with the decrease of the yield stress. The curves are nearly coincident for lower values of applied load in SS304L, which 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 ‐60 ‐40 ‐20 0 20 40 60 δ p [μm] Variation of yield stress [%] AA7050‐T6 SS304L -1000 -800 -600 -400 -200 0 200 400 600 800 1000 0 0.005 0.01 0.015 0.02 0.025 σ YY [MPa] ε YY [-] Y025 Ref GP 1 148 (a) (b) (a)