A novel measure for the material resistance to ductile fracture propagation under shear-dominated deformation
Theoretical and Applied Fracture Mechanics
Our engineered metallic materials are being designed to be more and more ductile with an increase in strength. Consequently, the failure mode has changed – from brittle to ductile fracture, which leads to a limited applicability of the previously used parameters that quantify the material resistance developed for brittle fracture. This is owing to that a considerable amount of plastic strain is introduced to the fracture process. Shear-dominated ductile fracture failure is commonly observed in many of the structural metals. In the current work, a novel measure Omega Ω is proposed, which fundamentally describes the material's ability to motivate relative mass motion in response to Mode Ι shear-dominated fracture propagation. The effects of specimen geometry, fracture tip constraint and deformation modes on Ω were discussed and analysed, which inspired the ideas of normalisation approaches that lead to the development of a dimensionless parameter Normalised Omega Ω¯. Accompanying with this concept, our systematically conducted experimental results (DWTT and SENT) indicated, that Ω¯ is independent to both in-plane and out-plane (specimen thickness) specimen configurations. So that it possesses the characteristic of being an intrinsic material constant for ductile fracture under shear mode.
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