Estimation of non-linear deflection for cylinder under bending and its application to CANDU pressure tube integrity assessment

This paper proposes engineering estimation equations for the maximum deflection of a cylinder subject to bending under elastic-plastic and elastic-creep conditions. Being based on the reference stress approach, the proposed equations are simple to use and can accommodate general tensile and creep behaviors. Validation against detailed 3D finite element (FE) results using actual stress-strain data and realistic creep-deformation data shows excellent agreement, which provides confidence in the use of the proposed equation. Based on the proposed equations, together with information on in-service inspection data, discussion is given how to estimate future time-dependent and time-independent deflection of the CANDU pressure tube. Thus, the present result would be valuable information for integrity assessment of the CANDU pressure tube.