NEW PERSPECTIVE IN THE VIBRATION BASED NDT RESEARCH FIELD

摘要

During last years aim of the authors has been the development of a NOT strictly responding to most of the mandatory requirements for effective health monitoring systems, while contemporary reducing the complexity of the data analysis algorithm and of the experimental acquisition instrumentation. From the algorithm's point of view, the proposed method is based on the acquisition and comparison of Frequency Response Functions (FRFs) of the monitored structure before and after a damage occurred. From an architectural point of view, many different system have been, during the last years, tested; they mainly differed for the actuators and sensors peculiarities and for the FRF's acquisition technique. On the actuators and sensor field, both piezoceramic and or PVDF patches and magnetostrictive actuators were tested referring to lightweight and/or heavy structures as well as to frequencies range of investigation. Also different vibration's measurement techniques have been tested and compared. This difference mainly refer to the excitation/acquisition structural point whose distinction or coincidence conduce to a cross-talking or self-sensing technique. A large number of structures and typological damages have been during these years deeply investigated, both by an experimental and numerical point of view, to assess and compare the approaches. In the different section of the paper an overview of all these topics will be presented manly as an opportunity to discuss peculiarities, advantages and drawbacks relative to the different approaches.