Influence of bend geometry on lifetime of pipe system under creep

The effect of variability in the wall thickness of bends in a piping system on the redistribution of stresses, creep damage and service life of systems was studied. These quantities, associated with a specific bend of system, have been demonstrated to be invariable with respect to any change in wall thickness in other bends along the piping system. Based on this observation, a probabilistic model of the service life calculation was compiled, taking into account the redistribution of stresses in the piping system due to thermal dilatation, scatter of the creep material properties and random variability of the wall thickness.