Fatigue Crack Growth and Stress‐Based Assessment of a Wind Turbine Main‐Bearing Model Under Simulated and Monitoring‐Based Inputs

ABSTRACT Wind turbine main‐bearing crack assessment requires consistent treatment of material crack growth and operating‐load uncertainty. Fatigue crack‐growth tests were performed on GCr15 0.5‐T CT specimens at , 0.10, and 0.50, and Paris parameters were identified. Finite element simulation at agreed with experiments within 15%. A laboratory‐scale NU205E surrogate was then used for static contact analyses with prescribed semielliptical raceway cracks. Increasing surface‐crack length caused a nonlinear rise in maximum von Mises stress, whereas increasing crack depth reduced the local maximum because of stress redistribution. A normalized Basquin‐based fatigue‐life index was used only for comparative assessment. The monitoring response–based equivalent input produced higher local stresses than the simulated input, increasing inner‐ and outer‐raceway peaks by 16.7% and 26.4%, respectively. The framework distinguishes local stress response from fracture mechanics–based remaining life.