Theoretical and finite element analysis of a laminated composite pipe under combined axisymmetric loading

Resumo

An essential aspect of hydrocarbon exploitation in offshore fields is ensuring the integrity of the
employed flexible pipes. In deep and ultradeep waters, new materials, structural configurations, and numerical
and experimental methodologies are required to obtain viable solutions depending on the operational and
environmental conditions. For instance, flexible pipes typically employ steel armors to resist the imposed
mechanical loads. However, the dimensions of these armors significantly increase with increasing water depths,
frequently causing the overload of the top supporting structures in floating production systems. Moreover, these
armors are particularly sensitive to stress corrosion cracking (SCC) when transporting fluids rich in
contaminants. Aiming to overcome these difficulties, a viable alternative to the typical flexible pipes is the
thermoplastic composite pipe (TCP), which is lighter and insensitive to SCC. Hence, this work investigates the
response of a composite pipe to combined axisymmetric loadings with two models: an analytical model based on
equilibrium and compatibility equations; and a finite element (FE) model. The responses obtained with both
models are compared in a parametric study, where the lay-up of the pipes and the operating temperatures are
varied. Finally, the burst pressures of these pipes are predicted following different failure criteria.