Coupled thermomechanical analysis of thermoplastic composite pipe by FEM simulations

Spoolable thermoplastic composite pipe (TCP) is an ideal alternative to traditional, heavier metallic counterparts for deepwater riser applications. During operation the pipe is subjected to mechanical loads simultaneously with through-wall thermal gradients arising from the mismatch between temperatures of hot pipe contents and cool surrounding ocean. In this work, structural analysis of TCP under coupled thermomechanical loads is performed using the finite element method (FEM). Temperature-dependent material properties are considered. Material safety factors for different laminate stacking sequences are compared and multi-angle stacking is shown to be effective for both pressure-and tension-dominated scenarios. Safety factors are also generated for TCP bent at reduced and elevated temperatures illustrative of spooling in different environments. It is clear that optimising the laminate for operation will adversely affect spooling capacity and vice-versa, i.e. TCP intended for extreme in-service conditions will require large spools.