Field calibration for torsional vibration sensor

A method for calibrating an output of a torsional vibration transducer, comprising:

• receiving, by one or more processors, a first plurality of zero-stress measurements of a shaft acquired by a torsional vibration transducer while the shaft is static across a plurality of gaps between the torsional vibration transducer and the shaft;
• receiving, by the torsional vibration transducer, a second plurality of zero-stress measurements of the shaft acquired by the torsional vibration transducer during rotation of the shaft about an axis of rotation and at a single gap between the torsional vibration transducer and the shaft;
• calculating, by the one or more processors, at least one calibration coefficient using the first and second plurality of zero-stress measurements;
• and
• calibrating, by the one or more processors, the output of the torsional vibration transducer according to the at least one calibration coefficient to reduce a sensitivity of the torsional vibration transducer to changes in gap between the torsional vibration transducer and the shaft when a torsional vibration of the shaft is measured.