Analytical Stress Intensity Factors for cracks at blunted V-notches

AbstractAn analytical expression for the Stress Intensity Factor (SIF) related to a crack emanating from a blunted V-notch root is put forward. Different notch amplitudes, ranging from 0° to 180°, and different crack length to root radius ratios, ranging from 0 to 10, are taken into account. The analysis is limited to mode I loading conditions, as long as the crack length is sufficiently small with respect to the notch depth. The proposed formula improves significantly the predictions of the relationships available in the Literature, by considering a notch amplitude dependent parameter: its values are estimated through a finite element analysis (FEA)

Finite Fracture Mechanics and Cohesive Crack Model: Size effects through a unified formulation

Finite Fracture Mechanics and Cohesive Crack Model can effectively predict the strength of plain, cracked or notched structural components, overcoming the classical drawbacks of Linear Elastic Fracture Mechanics. Aim of the present work is to investigate size effects by expressing each model as a unified system of two equations, describing a stress requirement and the energy balance, respectively. Brittle crack onset in two different structural configurations is considered: (i) a circular hole in a tensile slab; (ii) an un-notched beam under pure bending. The study is performed through a semi-analytical parametric approach. Finally, theoretical strength predictions are validated with experimental results available in the literature for both geometries, and with estimations by the point criterion in the framework of Theory of Critical Distances