Effect of notch depth on strain-concentration factor of notched cylindrical bars under static tension

The effect of the notch depth on the strain-concentration factor (SNCF) is studied for circumferentially notched cylindrical bars under static tension. The employed new SNCF is defined under the triaxial stress state at the net section. The elastic SNCF increases as the net-to-gross diameter ratio d0/D0 increases and reaches a maximum at the depth of d0/D0≈0.7. Beyond this value of d0/D0 it rapidly decreases to the unity with d0/D0. The elastic SNCF of the extremely deep notch of d0/D0=0.2 is almost equal to that of the shallow notch of d0/D0=0.95. Nevertheless, the SNCF of the shallow notch sharply increases with plastic deformation at the notch root, while the SNCF of d0/D0=0.2 increases only slightly. The SNCF of the deep notch of d0/D0=0.6 also increases with plastic deformation and reaches a peak value. This peak value is nearly equal to or slightly lower than that of the shallow notch and hence the plastic SNCF of shallow notches cannot be neglected. The variations of the SNCF with P/PY, the ratio of tensile load to that at yielding at the notch root, depends only on the notch geometry up to general yielding.