Saeid Hadidimaud - Assistant Professor, Ferdowsi University, Iran / visiting fellow, University of Bristol, UK; Dr., Mechanical Engineering, University of Bristol, BS۸ ۱TR, UK , Mechanical Engineering, Ferdowsi University of Mashhad, Iran
David Smith - Faculty Director of Research and Head of Structural Integrity; University of Bristol, UK; Prof. Mechanical Engineering, University of Bristol, BS۸ ۱TR, UK

One critical issue in the integrity assessment of pressurised vessels to be addressed is characterising the influence of initial residual stresses (arising from fabrication processes especially around welds, where the appearance of cracks is also a likely event) on cleavage fracture. Using a specific crack configuration, this paper explores the stress state at crack tip area under similar loading conditions with and without the presence of initial stresses as well as their interaction and compares the stress fields in the context of stress based statistical modelling of cleavage fracture toughness. A recently developed local stress based approach to failure probability prediction for cleavage fracture of ferritic steels is used to predict toughness distributions. It is found that the presence of initial residual stresses dramatically change the final fracture conditions.

Interaction, residual stress, cleavage fracture, pressure vessel, finite element method