Models and criteria of fracture mechanics in terms of the
notch stress intensity factor and J-integral are adopted for describing
deformation and fracture of a solid with a notch.
The notch failure assessment diagram is constructed as the
unified diagram for a notch as well as a crack. Effects of local constraint are
incorporated into basic criteria equations which allow estimating the notch
constraint-dependent fracture toughness and notch failure assessment diagrams
for various components with a notch and various types of loading.
The volumetric method suggested has been discussed from a
viewpoint of 3D finite element analysis of the elastic-plastic stress along the
crack front under uniaxial and biaxial mode I loading.
Calculation of the J-integral in plates with lateral and
central U- and V-blunt notches under mode I loading can be based on approximate
analytical formulas taking into account both a linear elastic and nonlinear
The load separation concept has been described to measure
the notch fracture toughness using non-standard notched specimens and the mixed
(modes I+II) J-integral in the case of the tension plate with an inclined centre
crack for power law hardening material.
Keywords: notch failure assessment
diagram, notch fracture toughness, constraint factor, 3D effective distance,