An analysis of Lode effects in ductile failure

Ductile Fracture in Plane Stress

“…In a recent work, Torki et al [19] have provided a rationale for measured failure loci in plane stress. The physical mechanism is void-mediated failure, irrespective of stress state.…”

“…Here, the isotropic mechanism-based ductile failure theory developed in Ref. [19] is employed to reproduce fracture loci in sheet metal using experimental data from the literature. To this end, adjustable parameters are introduced in the porous material constitutive relations similar to the well-known Tvergaard parameters for Gurson-like constitutive relations [20,21].…”

“…An essential feature of the theory in Ref. [19], and arguably of any isotropic theory that proceeds from first principles, is prediction of infinite ductility in shear. To rationalize finite strains to failure under shear-dominated regimes, the aforementioned theory is supplemented with a simple anisotropic model [22].…”

“…In a continuum description, the intervoid ligaments are represented by bands. When inhomogensous yielding is active, band orientation is solely determined by the macroscopic stress state for statistically isotropic and dilute void dispersions [19].…”

“…( 5), σ eq = 3 2 σ ′ : σ ′ is the von Mises stress, σ m is the mean normal stress, σ is the matrix yield strength, f is the void volume fraction, w is the void aspect ratio (w > 1 for prolate voids), and C, g, and κ are functions of f and w; see Ref. [19] for C and Ref. [23] for others.…”