A review of some recent data from multiaxial fatigue data from different notched materials is carried out in the paper. The approach based on the strain energy density (SED) averaged over a control volume is first used to summarise uniaxial and multiaxial fatigue strength data of welded joints made of structural steel and aluminium alloys. In all welded joints, the weld toe and weld root regions are modelled like sharp, zero radius, V-notches with different opening angles. The control volume radius is 0.28 mm for structural steels, 0.12 mm for aluminium alloys. Afterwards the SED approach is applied to multi-axial fatigue data from plain and V-notched specimens made of AISI 416 stainless steel (hardened and tempered state), subjected to tension, torsion and combined tension and torsion, both in-phase and out-of-phase. Notched specimens are characterised by a very small root radius, ρ=0.1 mm, which results in high nonlinear effects ahead of the notch tips. All results are summarised in terms of Δ W-N (SED range versus cycles to failure) scatterbands. Together with the new results, a number of multi-axial fatigue data recently obtained from sharply notched specimens made of C40 steel (normalised state) and 39NiCrMo3 steel (hardened and tempered state) are represented with the aim to provide a global synthesis in terms of local SED. Finally a synthesis from Ti6Al4V alloy is carried out showing the capability of the SED approach to be applied also to light alloys.

The linear elastic analysis of homogeneous, isotropic cracked bodies started in the 1900s. The existence of three dimensional corner point effects in the vicinity of a corner point where a crack front intersects a free surface was investigated in the late 1970s. An approximate solution by Bažant and Estenssoro explained some features of corner point effects but there were various paradoxes and inconsistencies. Results derived from finite element models showed that the analysis is incomplete. The stress field in the vicinity of a corner point appears to be the sum of two different singularities (i.e. stress intensity factors and corner point singularities). In this paper some recent results for the corner point singularities under in and out of plane loadings is reviewed and discussed.

In this paper, a volume criterion based on a simple scalar quantity, the mean value of the strain energy (SED), has been used to assess the static strength of notched components made of Polymethylmethacrylate (PMMA). The local-strain-energy based approach has been applied to a well-documented set of experimental data recently reported in the literature. Data refer to blunt U-notched cylindrical specimens of commercial PMMA subjected to static loads and characterised by a large variability of notch tip radius (from 0.67 mm to 2.20 mm). Critical loads obtained experimentally have been compared with the theoretical ones, estimated by keeping constant the mean value of the strain energy in a well-defined small size volume. In addition, some new tests dealing with V-notched specimens with end holes have been carried out to investigate the effect of the notch opening angle.