Failure analysis of tidal turbine blades: understanding erosion mechanisms and their impact on structural integrity

• First comprehensive review of erosion mechanisms in tidal turbine blades • Integrates structural and hydrodynamic perspectives on blade erosion impacts. • Examines synergistic effects of erosion with fatigue, corrosion, and biofouling. • Identifies research gaps and future directions for erosion-resistant blade design. Tidal energy presents a promising renewable resource; however, the reliability of turbine systems remains a critical challenge. Erosion of turbine blades, driven by mechanisms such as cavitation, abrasion, and suspended sediment impact, compromises both structural integrity and hydrodynamic performance over extended operational periods. Horizontal-axis tidal turbines equipped with composite blades have emerged as a leading technology that demands long-term durability in marine environments. Polymer composites offer favourable strength-to-weight characteristics, yet their susceptibility to moisture, dynamic loading, and surface degradation must be carefully managed. Predicting and mitigating erosion remains complex due to the diverse range of contributing factors, including flow friction, cavitation-induced microjets, and abrasive particles. The severity and localisation of erosion are strongly influenced by site-specific operational and environmental conditions, progressing from micro-scale pitting to material loss and surface roughening. Accurate metrology techniques and controlled experimental studies, when coupled with multiphysics simulations, can support the design of erosion-resistant materials and blade geometries. Leading-edge erosion is of particular concern, as it disrupts flow separation and stall characteristics, resulting in reduced lift and long-term power loss. Validated numerical models enable insight into these effects beyond the scope of physical testing. This review promotes an integrated framework that links materials research, erosion monitoring, and predictive modelling to inform the development of durable turbine blades. Advancements in these areas are essential for extending maintenance intervals, improving operational efficiency, and unlocking the full potential of tidal energy conversion technologies in challenging offshore environments.