Experimental investigation on void and compressive response of CNTs reinforced filament-wound riser with metal liner

Abstract

This study aims to explore the morphology of void and compressive performances of CNTs-reinforced filament-wound risers under axial compressive loading. The porosity morphology and distribution induced by the filament winding process were measured and analyzed, revealing a transition from nearly circular to elongated voids with gradual growth in the size of the individual void as the winding angle increased. Failure modes of composite risers were comprehensively discussed to understand the progressive failure process and load-bearing capacity. The results indicated that failure mechanisms of composite risers mainly manifest as initial resin splitting at the end of the structure, cracks growing in the interwoven region and local buckling at the end of the structure, and local asymmetric buckling as winding angle increased. While the addition of CNTs enhances the brittleness of the substrate and leads to an increased probability of debonding and delamination. Furthermore, the experiment results demonstrate that the energy absorption capacity can be generally improved at larger winding angles for the composite riser with 3% and 5% of CNTs volume content. The maximum values of peak crushing load, mean crushing force, energy absorption, and specific energy absorption were observed in the circumferentially wound riser with 5% of CNTs volume content.