A simple method of estimating the maximum normal stress and plastic zone size at a shallow notch

The maximum normal tensile stress at a shallow notch is used elsewhere to define a threshold level for the initiation of delayed hydride cracking at blunt notches in the pressure tubes of CANDUTMnuclear reactors. A simple method, based on a modified Neuber's solution, combined with the slip-line theory, is proposed to estimate the maximum tensile stress and the plastic zone size at a shallow notch under plane strain conditions. The applicability of the method is expected to be limited to non-workhardening materials having a high Young's modulus. Good agreement is found between the results of this simple method and finite element calculations applied to a cold-worked Zr-2·5Nb pressure tube material.