PSI - Issue 77

Tianyu Wang et al. / Procedia Structural Integrity 77 (2026) 512–520 Wang et al/ Structural Integrity Procedia 00 (2026) 000 – 000

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4. Parametric studies: influence of design on failure behaviour Following validation, authors conducted an extensive parametric study using the TLM to investigate the influence of key design parameters on the failure behaviour of composite pipes. This study focused on realistic loading scenarios relevant to the oil and gas industry, employing axisymmetric loads (133.5 kN axial compression, 51.7 MPa internal pressure, and variable torsional loads of 10 – 30 kN·m) and asymmetric loads (10 degrees/100 ft bending) [16]. The effects of the winding angle and stacking sequence were analysed as the torsional load component gradually increases, simulating the transition from static installation to dynamic operational conditions.

Fig. 3. Failure coefficients across the pipe thickness The first part of this study examined the performance of pipes with three strategically selected winding angle configurations: low-angle layup ( [+15°/−15°] 2 ), medium-angle layup ( [+45°/−45°] 2 ), and high-angle layup ( [+75°/−75°] 2 ). The research produced comprehensive diagrams clearly demonstrating the relationship between the maximum failure coefficient and applied torsional load for each configuration (see Fig. 3). Due to the effect of bending moment loads creating tensile and compressive stress fields on opposite sides of the pipe, the failure coefficient depends on the hoop coordinate; therefore, failure coefficients at critical positions ( 90° and 270° ) were analysed. At a baseline torque of 10 kN·m, the [+75°/−75°] 2 layup demonstrated optimal performance with the lowest failure coefficient of 0.35. This superiority stems from the near-circumferential fibre orientation that most effectively resists the hoop stress generated by the dominant internal pressure load. However, as the torque increases to 30 kN·m,