The Rise and Fall of the Rotor Blade Strain Gauge

In any gas turbine the understanding of the way in which the rotor blades vibrate is essential for both the development and production phases. For many years the standard method of obtaining such data has been with the use of strain gauges in conjunction with radio telemetry units or slip rings. With the complexity of the machine increasing and as the operating environment becomes more and more hostile for such systems, new methods are being investigated that will ultimately lead to a non-intrusive technology being developed. Here we review the progress and pioneers of strain gauge measurement dating back to the 1930s and look at a number of technologies that have tried to displace them from their positions as the mainstay of rotor blade vibration measurement.