Failure Analysis of Plastic Pipe Reinforced by Cross Helically Wound Steel Wire Subjected to Internal Pressure and Bending Load

Plastic pipe reinforced by cross helically wound steel wire (PSP) has been widely used in the transportation of petroleum, natural gas, municipal water, etc. In some serious occasions, PSP suffers from bending load caused by operating conditions such as ocean wave, pipeline laying and geological sedimentation, besides internal pressure. Thus, to understand the strength of PSP under the complex loads is crucial for ensuring safety. In this study, a finite element (FE) model of PSP was proposed by taking both internal pressure and bending load into consideration. By gradually increasing the bending load, the strength of PSP was obtained by taking the break of steel wires as the failure criterion. Then, combined loading tests were conducted to verify the proposed model. The results show that the applied bending loads bear a nonlinear relationship with the increasing deformation. By comparing experimental results and FE model calculation results, good agreement was obtained. Based on the verified FE model, the limit bending load and the effects of design parameters and internal pressure on the strength of PSP were discussed.