Effects of Reeling on Pipe Structural Performance—Part I: Experiments

Abstract

The winding and unwinding of a pipeline in the reeling installation process involve repeated excursions into the plastic range of the material, which induce ovality, elongation, and changes to the mechanical properties. The reeling/unreeling process involves some back tension required to safeguard the pipe from local buckling. This study examines the effects of winding/unwinding a pipe on a reel at different values of tension on the induced ovality and elongation and the resulting degradation in collapse pressure. In Part I, a model testing facility is used to simulate the reeling/unreeling process in the presence of tension. The combination of reel and tube diameters used induces a bending strain of 1.89%. A set of experiments involving three reeling/unreeling cycles at different levels of tension is performed on tubes with diameter-to-thickness ratios (D/t) of 20 and 15.5 in which the progressive changes in cross-sectional geometry and elongation are recorded. Both ovalization and elongation are shown to increase significantly as the back tension increases. A second set of experiments on the same two tube D/ts is performed in which following a reeling/unreeling cycle at a chosen level of tension, the tubes are collapsed under external pressure. The collapse pressure is shown to decrease significantly with tension, which is primarily caused by the reeling/unreeling-induced ovality. Part II presents models for simulating reeling and the induced structural degradation. The experimental results in Part I are used to evaluate the performance of the models.

Research on Dynamic Response of Pipeline under the Reeling Process and Laying Process

“…When subjected to the same curvature, the pipeline in the finite element simulation experiences higher moments, resulting in the phenomenon of the simulated ovality surpassing the theoretical ovality. Kyriakides [27] conducted a scaled-down experimental study with a diameter of 1 inch and a diameter-to-thickness ratio of 20 to investigate the relationship between ovality and curvature during the winding and unwinding processes of pipes. The experiments were repeated three times cyclically.…”

“…Subsequently, following this peak, a transient decay is observed, succeeded by a stable phase. This phenomenon can be attributed to the fact Kyriakides [27] conducted a scaled-down experimental study with a diameter of 1 inch and a diameter-to-thickness ratio of 20 to investigate the relationship between ovality and curvature during the winding and unwinding processes of pipes. The experiments were repeated three times cyclically.…”