Strain-Concentration Factor of Cylindrical Bars with Double Circumferential U-Notches under Static Tension

The interference effect on the new strain concentration factor (SNCF), which has been defined under triaxial stress state; is studied using the Finite Element Method (FEM).To this end, cylindrical bars with double circumferentially U-notches under static tension are employed. he new SNCF is constant in the elastic deformation and the range of this constant value increases with increasing notch pitch (lo) in the range 0.0 lo≤0.5 mm, then it decreases with increasing lo, and reaches a value nearly equal to that of the single circumferential U-notch. This becomes prominent with decreasing notch radius. As plastic deformation develops from the notch root; the new SNCF increases from its elastic value to a maximum value. On further plastic deformation, the new SNCF decreases with plastic deformation. The current results indicate that the notch pitch, where the interference effect is more pronounced on the new SNCF, is 0.0≤lo≤5 mm.