Method for monitoring the torsion of a rotary shaft on a turbomachine of an aircraft

1. A method for monitoring a torsion of a rotary shaft on an aircraft turbomachine based on the measurements from at least three sensor, wherein the at least three sensors include a first sensor, a second sensor, and a third sensor distributed along the rotary shaft to divide the shaft into at least two shaft segments, the method comprising:

a step of measuring, for each sensor, a parameter dependent on the rotation of the shaft,

a step of calculating, for each achievable pair of sensors, a parameter related to the torsion of the shaft, wherein the achievable pair of sensors include the first sensor and the second sensor, the first sensor and the third sensor, and the second sensor and the third sensor,

a step of comparing the different calculated parameters related to the torsion of the shaft with references,

a step of detecting damage on a shaft segment at the end of the comparison step, and

a step of indicating the localization of the damage on the shaft from the shaft segment for which damage has been detected.

2. The method for monitoring the torsion of a rotary shaft according to claim 1 , wherein at least one of the sensors used to localize the damage is a sensor permanently mounted on the turbomachine.

3. The method for monitoring the torsion of a rotary shaft according to claim 1 , comprising a preliminary step of installing at least one removable autonomous modular sensor, at least one of the sensors used to localize the damage being a modular, autonomous and removable sensor.

4. An assembly for monitoring a torsion of a rotary shaft on an aircraft turbomachine, the assembly comprising:

at least three sensors, wherein the at least three sensors include a first sensor, a second sensor, and a third sensor for measuring a parameter dependent on the rotation of the shaft, said sensors being distributed along the rotary shaft to divide the shaft into at least two shaft segments,

calculation means configured to calculate a parameter related to the torsion of the shaft for each achievable pair of sensors, wherein the achievable pair of sensors include the first sensor and the second sensor, the first sensor and the third sensor, and the second sensor and the third sensor,

comparison means configured to compare the different calculated parameters related to the torsion of the shaft with references,

means for detecting damage on a shaft segment from the information transmitted by the comparison means, and

means for indicating the localization of the damage on the shaft configured to indicate the damaged segment from the indication of the shaft segment for which damage has been detected by the detection means.

5. The assembly for monitoring the torsion of a rotary shaft according to claim 4 , wherein one of the at least three sensors used to localize the damage is a modular, autonomous and removable sensor.

6. The assembly for monitoring the torsion of a rotary shaft according to claim 4 , wherein each sensor is chosen among magnetic sensors, acoustic sensors, capacitive sensors and optical sensors.

7. A turbomachine configured to receive an assembly for monitoring the torsion of a rotary shaft according to claim 4 , the turbomachine comprising a housing and a hatch for accessing said housing for each sensor.

8. The turbomachine according to claim 7 , wherein at least one of the sensors is a sensor permanently mounted on the turbomachine.

9. An aircraft comprising at least one turbomachine according to claim 7 .