Abstract: The present disclosure discloses a method for detecting a natural frequency of a blade by a single blade tip timing sensor. In the method, two segments of displacement data vectors are subjected to dot product to obtain a product data vector after multiplication of corresponding serial numbers, the product data vector is subjected to low-frequency filtering, the filtered product vector is subjected to Hilbert transform to obtain an instantaneous phase, the instantaneous phase is subjected to discrete Fourier transform, an absolute value of a natural frequency difference between blades is extracted from amplitude frequency data, blades on a bladed disk are subjected to permutation and combination to obtain absolute values of the natural frequency differences between all the blades, a sum of the absolute values of the natural frequency differences between each blade and other blades is calculated.

Abstract: The present disclosure discloses a method for extracting a natural frequency difference between blades by a single blade tip timing sensor or uniformly distributed blade tip timing sensors. The method includes the following steps: acquiring actual arrival time of a rotating blade by using a single blade tip timing sensor or uniformly distributed blade tip timing sensors, and converting a difference between theoretical arrival time and the actual arrival time into displacement data of a blade tip according to a rotational speed and a blade length of the rotating blade; selecting displacement data of blade tips of two rotating blades with the same blade length at the same rotational speed; intercepting the displacement data, performing discrete Fourier transform respectively, and making a sampling frequency approximate to an average rotational speed to obtain spectrum data.