Adaptive structures for noise and vibration guidance, monitoring, and control

In this paper an overview is given on some relevant activities performed by CIRA within the field of noise and vibration, guidance, monitoring and control. Conventional microphones, piezoelectric materials and fiber optics are the sensing strategies used for the proposed applications. High level of integrability, wide operational frequency range are just some features that make them particularly suited for noise and vibration, structural monitoring and sensing, micro actuation and harvesting. The first study regards an active headrest system developed for aircraft cabin seats based on the filtered- X LMS algorithm. Experiments carried out on a mock-up of active headrest are described along with noise attenuation results in a representative acoustic field. After that, a structural monitoring application is presented via strain gauges, piezoceramic sensors, and fiber optics. A series of drop tests are executed on a representative model of a flexible fuel tank, that is dropped from a certain height on an instrumented steel plate and equipped with such deformation sensors. Finally, guided elastic waves generated by piezoelectric transducers are investigated for de-icing purposes. The development of such a specific technology has required the assessment of a dedicated approach that is addressed in this paper, along with its level of maturation and possible future developments.