Fatigue Life Prediction and Reliability Assessment of Cracked CFRP Laminates in WTBs Application: A Combined Approach Using Paris-XFEM and ALK Techniques

Wind turbine blades (WTBs) are crucial load-bearing components that ensure the safe and efficient operation of wind power systems. Carbon fiber–reinforced polymer (CFRP) composites, known for their low density and high strength-to-weight ratio, hold great promise for constructing larger and lighter blades. However, inherent manufacturing defects may cause crack propagation under fluctuating loads, thereby compromising the structural integrity of these components. Additionally, the complex fabrication processes and heterogeneous nature of CFRP composites result in variability in material properties, ultimately impacting their mechanical performance. This study examines the fatigue behavior of CFRP laminated plates with preexisting cracks, presenting a novel methodology to evaluate fatigue life and model reliability under conditions of uncertain material properties and loading scenarios. Static and fatigue tests were performed to quantify the effects of varying load levels and crack lengths on fatigue life. A simulation-based analysis, applying Paris’ law combined with the extended finite element method, offered a comprehensive evaluation of the fatigue crack propagation process. Fatigue life data were initially generated using finite element simulations, and an active learning Kriging surrogate model was developed, achieving an exceptional predictive accuracy of 99.96%. This model was subsequently employed to evaluate the fatigue reliability and conduct a sensitivity analysis of cracked CFRP laminates, laying the groundwork for the safety assessments and quality evaluations of wind turbine blades.