Finite Element Method for Sustainable Structural Integrity of Multi-bolted Flanges: A Review of Optimized Design and Green Maintenance Strategies

Multi-bolted flange (MBF) connections are essential components of piping systems, pressure vessels, offshore structures, renewable energy infrastructure, and process plants. However, their long-term reliability is often affected by complex mechanical loading, thermal cycling, gasket degradation, corrosion, bolt preload loss, and uneven force distributions. These technical challenges can lead to leakage, fatigue failure, unplanned shutdowns, repeated component replacement, and increased material waste. This review examines the role of the Finite Element Method (FEM) in improving the sustainable structural integrity of MBF systems through optimised design and green maintenance strategies. Recent studies have been synthesised to show how FEM supports stress distribution analysis, bolt preload evaluation, gasket contact-pressure prediction, fatigue life assessment, leakage prevention, corrosion risk evaluation, and structural health monitoring. Particular attention is given to how FEM-driven modelling can reduce overdesign, improve sealing performance, extend service life, and support predictive maintenance by identifying critical failure mechanisms before field failure. This review also highlights the importance of bolt modelling conditions, including preload definition, contact interaction, gasket compressibility, frictional behaviour, mesh refinement, and service-induced load combinations. Although FEM has significantly advanced the understanding of MBF performance, important research gaps remain in the integration of FEM with self-healing materials, real-time adaptive control, sensor-based monitoring, machine learning validation, and digital twin maintenance frameworks. Overall, this review demonstrates that FEM provides a practical pathway for achieving safer, more reliable, and more resource-efficient MBF systems while supporting sustainable engineering and environmental protection.