Damage Tolerance Assessment of Aging Nene X Turbine Discs

Abstract : ABSTRACT - The paper describes the application of the damage tolerance methodology to predict a safe inspection interval (SII) for the Nene-X engine turbine disc. The fracture critical location was established on the basis of stress analyses performed using 2D and 3D finite' element models. To establish the stress intensity factor dependence on crack size in the fracture critical location of the disc, finite element based fracture mechanics analyses were conducted for both through-thickness and thumbnail cracks with different surface-length to depth ratios. Fatigue crack growth rate data were generated on compact tension (CT) specimens machined from a high time disc. Deterministic fracture mechanics (DFM) and probabilistic fracture mechanics (PFM) calculations were performed to compute a safe inspection interval for the disc.