PSI - Issue 77

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2026) 000 – 000 Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 77 (2026) 512–520

© 2026 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ICSI organizers Abstract The study presents a novel two-level analytical framework based on three-dimensional elasticity theory that efficiently captures the complex stress interactions in thick-walled composite pipes subjected to simultaneous internal pressure, axial force, torsion, and bending. The model employs stress superposition to decouple axisymmetric and asymmetric loading effects, achieving computational efficiency improvements of two orders of magnitude compared to traditional finite element methods whilst maintaining comparable accuracy. Through comprehensive parametric studies, it was demonstrated that optimal fibre orientation is inherently load-dependent: high-angle layups ( ±75° ) excel under pressure-dominated conditions but exhibit rapid performance degradation with increasing torsional loads, whilst medium-angle configurations ( ±45° ) provide superior damage tolerance across varied loading scenarios. The study introduces an innovative ‘maximum load diagram’ methodology that transforms the design process from discrete point evaluation to continuous design space exploration, enabling identification of both global optima and manufacturing-robust plateau regions. These findings have immediate applications in subsea pipeline design, drill pipe optimisation, and broader implications for any cylindrical composite structure experiencing complex loading conditions. © 2026 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ICSI organizers Keywords: Thick-walled composite pipe, Combined loading, Drilling, Material failure, Analytical solution. International Conference on Structural Integrity Analysis and optimal design of thick-walled composite pipes under combined axisymmetric and asymmetric loading Tianyu Wang a,b , Oleksandr Menshykov c *, Mou Tang a , Marina Menshykova c a SINOPEC Petroleum Engineering Zhongyuan Co. Ltd., Puyang, Henan 457001, PR China b School of Material Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, PR China c School of Engineering, Fraser Noble Building, King’s College, University of Aberdeen, Aberdeen, AB24 3 UE, Scotland, UK

* Corresponding author. Tel.: +44-1224-273326 E-mail address: o.menshykov@abdn.ac.uk

2452-3216 © 2026 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ICSI organizers

2452-3216 © 2026 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ICSI organizers 10.1016/j.prostr.2026.01.064