Some methods for rapid evaluation of the mixed mode NSIFs

In this work three methods for the rapid calculation of the NSIFs, based on the averaged strain energy density (SED), are compared. The first method was proposed by Lazzarin et al. and it is based on the calculation of the SED averaged in two different control volumes centred at the notch tip. The second one instead was recently presented by Treifi et al. and it takes advantage of the strain energy density averaged within two control volumes (semi-circular sector) centred at the notch tip. Then a new method based on the evaluation of the total and deviatoric strain energy density averaged over a control volume has been proposed. Finally, the described methods have been applied to plates weakened by different V-notch geometries: diamond-shaped notch with two different opening angles, square hole and central crack in plates of finite and infinite extension. The values of the NSIFs derived according to Gross and Mendelson have been compared with those obtained by means of the approximate methods, by using coarse and refined FE meshes.