Robust fiber optic sensors for vibration diagnostics

We present a development study of a robust inter-ferometric transducer for elastic deformations excited by mechanical vibrations. In contrast to known methods using piezoelectric, fiber Bragg grating and Fabry-Perot interferometer sensors, we deal with pronounced spatially distributed transduction based on arbitrary shaped fiber segments like fiber optic coils. This approach allows, e.g., an omnidirectional sensitivity characteristic in case of circular shaped fiber segments, and offers a high immunity against electromagnetic interferences. Omnidirectional transducer characteristics are beneficial for vibration detection on complex shaped bodies. A finite element model simulation (FEM) is used to demonstrate the detection capacity for Lamb waves propagating in a carbon fiber reinforced polymer (CFRP) matrix.