Mechanical behavior of pipe reinforced by steel wires under external pressure

Abstract

Plastic pipe reinforced by helically cross-winding steel wire (namely PSP) is a novel kind of composite pipe which consists of an inner high-density polyethylene layer, steel wire layers and an outer polyethylene coating. PSP has the potential application as subsea pipeline. Based on numerical 2D ring model, proposed by Yong Bai, the wall thickness change, transverse shear deformation and pre-buckling deformation have been considered in the collapse investigation of PSP under external hydrostatic pressure. Based on finite element method, reinforced layers were taken as transverse isotropic material, and equivalent elastic modulus was obtained based on Halpin–Tsai model. It is shown that steel wires layer has little effect (just 0.2% difference) on the behavior of PSP under external pressure. The external pressure–ellipticity and external pressure–hoop strain curves derived from the theoretical method and finite element method are compared and show a good agreement (deviation of buckling pressure is 1.4%). Finally, maximum experimental external pressure values of two pipe specimens were obtained by increasing hydrostatic pressure in a closed cylinder. The results of theoretical analysis and finite element method are in great agreement with the experimental values.