Applicability of the fraction model to cyclic plastic deformation of pipeline steel

One of the concerns of a fitness for purpose analysis is the quantification of the relevant material properties. Experimentally it is found that the mechanical properties of a material can change due to a monotonic plastic deformation or a cyclic plastic deformation. For a fitness for purpose analysis to be accurate in these cases, it has to take into account the current mechanical properties of the material. The problem is that the current properties may not always be known. If the original properties would be used it could lead to non-conservative results for the fitness for purpose analysis. It is therefore desirable that the mechanical properties of the material after deformation can be estimated from the mechanical properties of the undeformed material. In this study it is shown that the fraction model can be useful in predicting the yield behaviour during cyclic plastic deformation. These numerical results are compared with experiments.