New Trends in Multifunctional Sensors for Rotating Systems

This paper reports on the design and testing of two novel classes of transducers for structural health monitoring and strain sensing particularly suited for harsh environments operations, as in the case of rotating systems. The design methodology takes advantage of the Fourier representation of the transducer and allows for smart patterning of the transducer inner shape, resulting in enhanced performance and reduced complexity of such devices. The first class of transducers leverages guided waves. For this, continuous beam steering and directional sensing are achieved either through proper selection of the excitation frequency (actuation mode), or through the detection of the dominant harmonic component in a recorded signal (sensing mode). The second class of transducers makes use of surface acoustic waves. The resulting device is an acoustic wave rosette, which enables simultaneous detection of three components of strain with a single device. The intrinsic different nature of the waves employed in the proposed classes suggests a potential combination of the two concepts, resulting in an enhanced device tailored for health and usage monitoring of structural components