Analysis of filament-wound sandwich pipe under combined internal pressure and thermal load considering restrained and closed ends

Sandwich pipe consisting of inner and outer filament-wound (FW) skins bonded to a core material is a lightweight alternative to single-wall or pipe-in-pipe systems. In operation the pipe is subjected to thermomechanical loading. In this paper, a 3D finite element model is developed for analysing stresses in FW sandwich pipe under combined internal pressure and thermal load, incorporating temperature-dependent properties. Optimal reinforcement angles are determined for axially restrained ends (as per a long pipeline) and closed ends (pressure vessel condition). The effects of uniform and non-uniform heating on stress-based failure are evaluated. The pipe thermomechanical response is shown to depend on whether the pressure loading is hoop-dominated or biaxial. The core of the axially restrained pipe is highly temperature-sensitive under low pressure. With closed ends the coupled effect of mechanical and thermal loading on the skins is significant. The influences of core thickness and number of skin plies are investigated.