Effect of notch depth on strain-concentration factor of rectangular bars with a single-edge notch under pure bending

The FEM is employed to study the effect of notch depth on a new strain-concentration factor (SNCF) for rectangular bars with a single-edge notch under pure bending. The new SNCF Kεnew is defined under the triaxial stress state at the net section. The elastic SNCF increases as the net-to-gross thickness ratio h0/H0 increases and reaches a maximum at h0/H0 = 0.8. Beyond this value of h0/H0 it rapidly decreases to the unity with h0/H0. Three notch depths were selected to discuss the effect of notch depth on the elastic–plastic SNCF; they are the extremely deep notch (h0/H0 = 0.20), the deep notch (h0/H0 = 0.60) and the shallow notch (h0/H0 = 0.95). The new SNCF increases from its elastic value to the maximum as plastic deformation develops from the notch root. The maximum Kεnew of the shallow notch is considerably greater than that of the deep notch. The elastic Kεnew of the shallow notch is however less than that of the deep notch. Plastic deformation therefore has a strong effect on the increase in Kεnew of the shallow notch. The variation in Kεnew with M/MY, the ratio of bending moment to that at yielding at the notch root, is slightly dependent up to the maximum Kεnew for the shallow notch. This dependence is remarkable beyond the maximum Kεnew. On the other hand, the variation in Kεnew with M/MY is independent of the stress–strain curve for the deep and extremely deep notches.