Vol.11, No1, 2011, pp. 3-7
UDC 539.42.013.3

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 elastic material.

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, J-integral