ORIGINAL RESEARCH article

Front. Mater.

Sec. Mechanics of Materials

Volume 12 - 2025 | doi: 10.3389/fmats.2025.1560428

Analysis of the Mechanical Behaviors of Nonmetallic Un-bonded Flexible Pipe under Different Loads

Provisionally accepted
Jin  YuJin Yu1Xuegang  YouXuegang You1Tianwei  KongTianwei Kong2*Mengying  XiaMengying Xia1Ruhong  LvRuhong Lv1Kezheng  ZhangKezheng Zhang1Baodong  WangBaodong Wang2
  • 1CNOOC Gas and Power Group Ltd., Beijing, China
  • 2China University of Petroleum, Beijing, Beijing, China

The final, formatted version of the article will be published soon.

The growing demand for lightweight, corrosion-resistant, and cost-effective solutions in offshore oil and gas operations has driven the transition from traditional metallic pipes to advanced non-metallic flexible pipes. A rigorous three-dimensional nonlinear finite element model was developed using ABAQUS/Explicit, incorporating actual material parameters, structural nonlinearity, and interlayer contact behavior. The model was validated through full-scale burst pressure tests, demonstrating excellent agreement (within 13.4% error) with experimental results. Key findings indicate that internal pressure of 35 MPa can increase tensile stiffness by up to 22.1%, while external pressure of 15 MPa enhances it by 8.9%. Under combined axial tension-bending loading conditions, the flexible pipe demonstrates higher bending stiffness compared to single-load scenarios. Internal pressure exhibits minimal influence on non-slip bending stiffness but simultaneously elevates both critical slip curvature and post-slip stiffness. In contrast, external pressure significantly improves both critical slip curvature and post-slip stiffness. These quantitative results provide crucial design guidelines for performance optimization of non-metallic pipes in deepwater applications.

Keywords: Nonmetallic unbonded flexible pipe1, mechanical behaviors2, nonlinearity finite element3, loads4, simulation analysis5

Received: 14 Jan 2025; Accepted: 30 Jun 2025.

Copyright: © 2025 Yu, You, Kong, Xia, Lv, Zhang and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Tianwei Kong, China University of Petroleum, Beijing, Beijing, China

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