Speed spectrum development method for engine fan disk

The fan disk is a critical fracture-prone component in aero-engines. To ensure its operational safety and reliability, it is essential to develop load spectra that accurately reflect operating conditions, which are crucial for fatigue life assessment. This study conducts statistical analysis of single-parameter loading on fan disks based on operational data from two mission types of a specific aero-engine, and develops a median speed spectrum through mission segment analysis methodology. The load spectrum damage was calculated using the SWT (Smith-Watson-Topper) equation and linear cumulative damage theory. Load spectrum similarity analysis was conducted with the DTW (Dynamic Time Warping) method. Based on group tests of TC17 titanium alloy simulated specimens, a damage analysis method based on load spectrum similarity was proposed. The damage of the fleet fan disk rotational speed spectrum was calculated to obtain a set of load spectrum damage samples. Goodness-of-fit tests indicate that the fan disk rotational speed spectrum damage follows a lognormal distribution. The damage corresponding to the median rotational speed spectrum closely approximates the median damage of the fleet rotational speed spectrum, validating the rationality of the spectrum development methodology. This provides critical support for accurately assessing the safe service life of fan disks.