Yield locus for circumferential part-through surface cracked pipes under combined pressure and bending

This paper provides analytical plastic limit load solutions of pipes with circumferential part-through surface cracks under combined pressure and bending. A key issue is to postulate discontinuous hoop stress distributions in the net-section. General equations for arbitrary-shaped cracks are derived and closed-form solutions are given for two idealized cracks; a constant depth crack and circular crack. Validity of the proposed limit load solutions are checked against the results from three-dimensional (3D) finite element (FE) limit analyses using elastic–perfectly plastic material behaviour.