On deviatoric interpretation of Neuber’s rule and the SWT parameter

In this paper a deviatoric interpretation of Neuber’s rule and Smith–Watson–Topper (SWT) parameter is presented and discussed. It is found that the deviatoric formulation of Neuber’s rule results in inelastic strains at notch-root that are between estimations obtained from traditional Neuber’s rule and the equivalent strain energy density method of Molski and Glinka. Based on an energy interpretation and some analogy with the Neuber’s rule a deviatoric interpretation of the SWT parameter called SWTD is discussed. It is found that for positive mean stresses and moderate negative mean stresses the traditional SWT parameter and the proposed SWTD parameter yield similar results. On the other hand, for large compressive mean stresses with a stress ratio R < −2 the proposed SWTD parameter demonstrates a fairly good correlation while the original SWT parameter results in wide scatter. It can be noted that results obtain with both the deviatoric Neuber’s rule and the SWTD parameter do not involve or require any additional constants or fitting parameters.