PSI - Issue 71

A.K. Dwivedi et al. / Procedia Structural Integrity 71 (2025) 142–149 = 2 ( 1− 2 ) + 2 ( 1− 2 )

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Here, K I is the stress intensity factors for mode I and K II for mode II loading. Under combination of mode I - mode II loading the parameter β is defined as . = 6 The stress versus strain curve under uniaxial tension is defined by the following equation- = { , ≤ 0 0 ( 0 ) , > 0 7 Where, E = Young’s modulus, σ 0 = yield stress, and n = hardening exponent, σ 0 /E = 0.004, ν = 0.333, and n = 0.1.

Fig. 1 (a) Two-dimensional modified boundary layer (MBL) model containing a blunt semi-infinite crack and discretely resolved two-scales voids. (b) P-0° distribution of primary voids and elliptical secondary voids in the of = 45° ( (c) P-45° distribution of primary voids and elliptical secondary voids in the of = 0° (d) aspect ratio of secondary void. (e) mesh near the crack-tip In this study, all the meshes are 2D, composed of 8-noded quadratic plane strain elements. A detailed views of the mesh showing P 0° and S 45° voids distribution ahead of crack tip are shown in Fig. 1e. The crack length is calculated as the sum of all the reduction in ligament in the path followed by the crack. The crack extension ∆a is calculated in terms of the normalized length of each intervoid ligament defined as χ i = W/W 0 . Here, W and W o denote the current and in the