On the use of the peak stress method to assess the linear elastic and the fatigue notch factors of notched components under tension

A simple method is proposed, which allows the theoretical stress concentration factor at a rounded notch tip to be assessed from the fictitious stress value arising at the tip of the corresponding pointed V-notch. Such a stress value suffices to be determined by a finite element analysis carried out using a mesh pattern with a constant average element size, d, strictly related to the actual root radius, , and the opening angle, 2 alpha, of the radiused notch. The relevant expression linking d to rho and 2 alpha is obtained in closed form and the accuracy of the proposed method is discussed versus the results of a number of finite element analyses carried out on notched plates under tension. Eventually, the possibility of using the peak stress directly as a strength parameter is explored, and an example related to the fatigue strength of welded joints is provided to support this idea.