Multi-scale modeling of plastic pipe reinforced by cross helically winding steel wires (PSP) under ground surcharge load

Ground surcharge can induce significant bending deformation of buried pipelines, which in turn leads to cross-sectional ovalization, plastic strain, or local buckling. In this paper, a multi-scale coupled finite element model of buried PSP under ground surcharge load is established by using ABAQUS and CATIA software to simulate their mechanical behaviors, which can achieve a sound balance between computational accuracy and efficiency. Combined with material tensile tests and full-pipe bending tests, the constitutive models of each material in the PSP and the bending performance of the whole pipe are obtained. The responses of the PSP, including the Mises stress of the high-density polyethylene (HDPE) matrix and helical steel wires, contact pressure (CPRESS), as well as the cross-sectional ovality are investigated in this paper. Furthermore, the effects of surcharge load magnitude, surcharge zone, and internal pressure are discussed. The results show that the Mises stress distribution on the outer surface of the HDPE outer layer exhibits significant spatial inhomogeneity; the surcharge load has an approximately linear positive correlation with the cross-sectional ovality and stress level of the buried PSP; the increase in surcharge zone will aggravate the inhomogeneity of CPRESS distribution, resulting in a nonlinear increase in ovality and stress; although the internal pressure can suppress the deformation caused by surcharge, it will significantly increase the stress level of steel wires.