The volume-based strain energy density approach applied to static and fatigue strength assessments of notched and welded structures

A large bulk of experimental data from static tests of sharp and blunt V-notches and from fatigue tests of welded joints are presented in an unified way by using the mean value of the Strain Energy Density (SED) over a given finite-size volume surrounding the highly stressed regions. When the notch is blunt, the control area assumes a crescent shape and R is its width as measured along the notch bisector line. In plane problems, when cracks or pointed V-notches are considered, the volume becomes a circle or a circular sector, respectively, with R0 being their radius. R0 depends on material fracture toughness, ultimate tensile strength and Poisson's ratio in the case of static loads; it depends on the fatigue strength δσAof the butt ground welded joints and the Notch Stress Intensity Factor (NSIF) range δK1 in the case of welded joints under high cycle fatigue loading (with δσA and δKJ valid for 5x106 cycles). Dealing with static tests, about nine hundred experimental data as taken from the recent literature are involved in the synthesis. The strong variability of the non-dimensional radius R/R0, ranging from about zero to about 1111, makes the check of the approach based on the mean value of the SED severe. In parallel, dealing with welded joints, nine hundred experimental data are here summarised in terms of the local SED.