Thermomechanical Analysis of Sandwich Pipes with Graded Core

Sandwich pipes consisting of inner and outer fibre-reinforced composite skins bonded to a core material are viewed as a lightweight alternative to single-wall pipes and pipe-in-pipe systems. Introducing a density gradient into the core material offers further possibility to improve the performance of these pipes when subjected to combined mechanical and thermal loads. In this paper, a Finite Element (FE) model for thermomechanical stress analysis of sandwich pipes with graded cores is developed and validated against the three-dimensional elasticity solution. An FE-based thermomechanical analysis of pipes with carbon/epoxy skins and graded polyvinyl chloride (PVC) core under loads relevant to offshore piping applications reveals that a graded core offers an attractive compromise in terms of pipe weight and stresses in the fibre layers when compared to sandwich pipes with non-graded cores.