Wideband fiber optic vibration measurement system prototype evaluation

Measurement performance comparisons are examined between a point-and-shoot Robust Laser Interferometer (RLI) and an RLI fiber optic prototype system design successfully demonstrated during seeded fault testing at Pratt and Whitney in support of technology investigations conducted for the Joint Strike Fighter (JSF) Program. The baseline point-and-shoot RLI system measurement capability is reviewed, including observation of the existence and character of time shock pulses, the measurement of envelope detection fault frequencies, and changes in the amplitude and character of spectra. The system designs and experimental approaches for developing the comparison measurements are outlined. The functional areas selected for comparison include background noise, large vibration and dynamic range measurements, large amplitude complex vibration measurements, and high frequency performance. While additional work is required for the RLI, it has been demonstrated that wideband vibration measurements, including measurement of acoustic emissions, can be provided by both baseline point-and-shoot and fiber optic RLI designs.