Session: 04-01-01 Flexible Pipes & Umbilicals I

Paper Number: 125247

125247 - Finite Element Analysis of Collapse in Thermoplastic Composite Pipes Under External Pressure 

Given the challenges the oil and gas industry faces in deepwater operations, including high hydrostatic pressures and severe stresses, the use of thermoplastic composite pipes (TCPs) is on the rise. The increasing application of these structures is attributed to their numerous advantages, which encompass their lightweight, high-performance, and resistance to stress corrosion cracking (SCC). Among the applications of TCPs is their use in hybrid flexible pipes, which consist of conventional flexible pipes with composite layers replacing steel armors. One of the most discussed configurations of hybrid flexible pipes involves replacing the central core of the flexible pipe, which includes the carcass, inner sheath, and pressure armor, with TCPs. In this scenario, the TCPs are responsible for resisting pressure. Therefore, this study proposes a finite element model to predict the potential collapse of TCPs under external pressure. The finite element (FE) model was developed using ANSYS®️, employing three-dimensional solid elements to represent the layers of the pipes. Parametric analyses were conducted to assess the effects of initial ovalities and explore some laminate combinations. Additionally, some failure criteria for composite materials are employed to predict collapse pressure and compare it with the results derived from the finite element model. In these analyses, lay-ups with higher winding angles have shown improved performance. However, it notes that axial resistance decreases with higher winding angles, emphasizing the importance of fiber orientations due to complex loads in risers. Initial ovality impacts deformation more than the capacity for collapse loads. Finally, the failure criteria aligned well with the FE model, with Tsai-Wu demonstrating better accuracy.

Presenting Author: Inês Freitas UFRJ - Federal University of Rio de Janeiro

Presenting Author Biography: Civil Engineer graduated from the Federal University of Pará, master in Structures from COPPE/Federal University of Rio de Janeiro and PhD candidate in Structures from COPPE/Federal University of Rio de Janeiro. Currently, she is a researcher at the Offshore Structures Analysis and Reliability Laboratory (LACEO / UFRJ). Working mainly on the following topics: thermoplastic composite pipelines, hybrid flexible pipelines, analysis of offshore structures, numerical modeling of structures, sizing and structural verification.

Authors:

Inês Freitas UFRJ - Federal University of Rio de Janeiro
José Renato Sousa UFRJ - Federal University of Rio de Janeiro
Winston C. e Gama Petrobras
Charlton Souza Petrobras