STRAIN-CONCENTRATION FACTOR OF CIRCUMFERENTIALLY V-NOTCHED CYLINDRICAL BARS UNDER STATIC TENSION

The FEM is used to study the effects of notch opening angle (beta) and notch radius on the new strain-concentration factor (SNCF) for circumferentially V-notched cylindrical bars under static tension. The new SNCF has been defined under the triaxial stress state at the net section. Nevertheless, the conventional SNCF has been defined under uniaxial stress state. The new SNCF (K-epsilon(new)) is constant in the elastic deformation. The range where this elastic K-epsilon(new) value remains constant increases with increasing S and increasing notch radius (rho(o)). The effect of the notch opening angle on the elastic K-epsilon(new) decreases with increasing rho(o). Particularly, the elastic K-epsilon(new) of beta = 120 degrees is the minimum for all notch radii employed. The new SNCF increases from its elastic value to a peak value and then decreases with plastic deformation for notches with beta = 120 degrees. This peak value is the maximum K-epsilon(new). Nevertheless, K-epsilon(new) for the notches with beta < 120 degrees becomes nearly constant or slightly decreasing after the first peak for rho(o) = 0.5 and 1mm. After that it increases to the maximum SNCF and then slightly decreases for further plastic deformation. The variations in K-epsilon(new) with the ratio of tensile load to that at yielding at the notch root (P/P-Y) are nearly independent of stress-strain curve up to general yielding.