Abstract: A rotor assembly (30) comprising a rotor (32) having an annular array of rotor blades (34), the rotor mounted to a shaft (38). A phonic wheel (40) coupled to the shaft. A speed sensor (44) axially aligned with the phonic wheel and configured to measure voltage (V), amplitude of the voltage being proportional to clearance (46) between the sensor and phonic wheel. A processor (48) configured to: receive the voltage measurement; derive shaft speed (?) from the voltage measurement; identify modulation of the voltage amplitude at a frequency which is an integer multiple of the shaft speed; compare voltage amplitude to a threshold; and output a rotor damage signal based on the comparison.

Abstract: A rotor assembly (30) comprising a rotor (32) having an annular array of rotor blades (34), the rotor mounted to a shaft (38). A phonic wheel (40) coupled to the shaft. A speed sensor (44) axially aligned with the phonic wheel and configured to measure voltage (V), amplitude of the voltage being proportional to clearance (46) between the sensor and phonic wheel. A processor (48) configured to: receive the voltage measurement; derive shaft speed (?) from the voltage measurement; identify modulation of the voltage amplitude at a frequency which is an integer multiple of the shaft speed; compare voltage amplitude to a threshold; and output a rotor damage signal based on the comparison.

Abstract: A method of simulating life of a rotor blade mounting feature mounted in a complementary rotor disc mounting feature comprises the steps of providing two specimen mounting features (37) each having portions defining pressure faces matching in profile respective faces of the rotor blade mounting feature; providing a fixture (38) having two opposed mounting features (39) each having portions defining pressure faces (78) matching in profile respective faces of the rotor disc mounting feature; mounting the specimen mounting features (37) in the fixture mounting features (39); applying a first load to the specimen mounting features (37); measuring a strain in a region (86) of the fixture (38) between the fixture mounting features (39); applying a second load to the fixture (38), the second load being substantially perpendicular to the first load; and controlling the second load in response to the measured strain. A high cycle load may simultaneously be applied to the specimen mounting features (37).