Application of fibre optic sensing systems to measure rotor blade structural dynamics
| Autor: | Thomas Kissinger, Ralph P. Tatam, James H. Barrington, Simone Weber, E. Chehura, Mohammad M. Lone, Stephen W. James, Ivan Petrunin, Kevin Mullaney, Stephen E. Staines, Luca Zanotti Fragonara |
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| Rok vydání: | 2021 |
| Předmět: |
0209 industrial biotechnology
Optical fiber Materials science Acoustics Aerospace Engineering 02 engineering and technology bearingless main rotor blade 01 natural sciences law.invention shape measurement 020901 industrial engineering & automation Fiber Bragg grating law Normal mode 0103 physical sciences 010301 acoustics Strain gauge Civil and Structural Engineering Rotor (electric) Mechanical Engineering Computer Science Applications Vibration Interferometry bre Bragg gratings Control and Systems Engineering Signal Processing Neutral axis |
| Zdroj: | Mechanical Systems and Signal Processing. 158:107758 |
| ISSN: | 0888-3270 |
| Popis: | This paper compares two fibre optic sensing techniques for vibration characterisation: (a) optical fibre Bragg grating (FBG) strain gauges and (b) a novel direct fibre optic shape sensing (DFOSS) approach based on differential interferometric strain measurements between multiple fibres within the same fibre arrangement. Operational mode shapes and frequency measurements of an Airbus Helicopters H135 bearingless main rotor blade (5.1 m radius) were acquired during a series of ground vibration tests undertaken in a controlled laboratory environment. Data recorded by the fibre optic instrumentation systems were validated using commercially available accelerometers and compared against a baseline finite element model. Both fibre optic sensing systems proved capable of identifying the natural frequencies of the blade in the frequency range of interest (0–100 Hz). The data from the FBG sensors exhibited a dependency on their position relative to the neutral axes of the blade, which meant that full characterisation of the flapping and lagging modes required careful consideration of sensor location in the chordwise direction. The DFOSS system was able to identify all structural dynamics, despite being located on the neutral axis in the lagging direction, due to its sensitivity to angle changes, rather than strain, and its biaxial measurement capability. The DFOSS system also allowed the operational mode shapes of the blade to be determined directly, without the requirement for strain transfer from the blade to the sensor and without the requirement for a model of the underlying structure. The accuracy of obtained natural frequencies and operational mode shapes is assessed, demonstrating the potential of the use of both fibre optic sensing systems for determining blade structural dynamics. |
| Databáze: | OpenAIRE |
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