PSI - Issue 80

Sherif Ezzeldin et al. / Procedia Structural Integrity 80 (2026) 195–202 S. Ezzeldin / Structural Integrity Procedia 00 (2023) 000–000

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2. Finite Element Model

The HDPE flange connection was modeled in Abaqus / Standard Abaqus (2014) with a steel blind flange, backing ring, and HDPE pipe stub-end fastened by eight bolts (Fig. 1). Surface-to-surface contact with a friction coe ffi cient of 0.2 was used Shahin et al. (2021), and all components were meshed with C3D20R elements, refined at contact zones. A mesh convergence study confirmed that 140,215 elements ensured solution accuracy Ezzeldin et al. (2025). Unlike previous work—which focused on validating TAM and EICM without internal pressure—this study evaluates the tightening procedure under operational conditions, applying P = 0 . 9 MPa to determine required bolt loads and assess leakage via average contact stress. Based on TN-38 Plastic Pipe Institute (2019), a seating stress of 4 MPa yields a final bolt load F fb = 19 . 88kN; thus, F d = 20 kN is adopted, consistent with Ezzeldin et al. (2025). To ensure tightness, an average contact stress of 2.85 MPa—slightly above the calculated 2.83 MPa (3.14 × P) Plastic Pipe Institute (2019); Shahin et al. (2021)—is set as the leakage threshold.

Fig. 1: FEA model of the HDPE flange connection with ISO 9624:2019 ISO 9624 (2019); Ezzeldin et al. (2025) (dimensions in mm).