Numerical modelling of spoolable thermoplastic composite pipe (TCP) under combined bending and thermal load

Spoolable thermoplastic composite pipe (TCP) consisting of fibre-reinforced laminate with inner and outer liners is an ideal candidate to replace steel counterparts in deepwater. In this paper, a 3D finite element (FE) model is developed to analyse stresses in TCP under combined bending and uniform temperature change illustrative of spooling in different environments. Thermal load causes deviation from the stress symmetry expected at the top/bottom of the pipe in simple bending. Maximum stress, Tsai–Hill and Hashin failure responses are analysed for [±55]₄, [±42.5]₄, [±30]₄ and [(±55)₂/(±30)₂] laminates at low and high temperatures. The [±42.5]₄ configuration displays superior spooling capacity as layers orientated at ±55° and ±30° exhibit high utilisation of relatively weak transverse tensile and fibre compressive strengths, respectively. The failure criteria are in closest agreement at the top of the pipe (under axial tension) but differ more significantly at the bottom (axial compression).