An improved crack driving force estimation approach for stress-based engineering critical assessment of reeled pipes

In the study, an improved reference load solution is proposed to determine the reference stress and the J-integral for pipelines subjected to reeling, where the axial strains during installation are typically within the range of 1.5%–3.5%. Accordingly, the reference stress can be directly correlated with the un-cracked remote stress of the component through the loading-independent parameter, λ. The effects of cracked geometries and material properties on the reference stress are systematically investigated, and an empirical formula for the reference stress is provided. The proposed method is validated against various J estimation schemes in the literature. It is concluded that the present reference load solution is able to provide an improved and simplified J-integral estimation for the considered geometries over the full strain range of interest.