Stress concentration factors of flat end to cylindrical shell connection with a fillet or stress relief groove subjected to internal pressure

Abstract For fatigue assessment of pressure vessels (parts), as proposed by the CEN Technical Committee 54, the knowledge of some stress quantities in the structure is necessary, e.g. equivalent stresses according to Tresca's yield criterion and principal stresses at welds. In this article, these quantities are given in the form of stress concentration factors for the flat end to cylindrical shell connection with a fillet or stress relief groove subjected to internal pressure. In this context, a stress concentration factor is defined as the ratio of the ‘true’ stress (obtained by FE analysis) to the analytically determined stress corresponding to the linear elastic idealized shell plate model. For different values of the ratio of fillet/groove-radius to plate thickness, approximation functions for those stress concentration factors are obtained, covering the range of conventional flat end to cylindrical shell connection geometries.