Development of Surface Acoustic Wave pressure sensors for monitoring concrete structures
Résumé
For many years surface acoustic waves (SAW) have been used in manufacturing electronic components for industrial and sensing applications. Due to the absence of an embedded electronic system and the possibility of wireless communication this technology can offer a great solution for sensing in harsh environments such as high pressure, temperature and humidity. In the case of refractory concretes, the optimization of the drying cycles has indeed a significant economic impact (reduction of the downtime of the manufacturing lines, energy cost) while making them more efficient and limiting the risks of structural damage. The current sensors on the market are too restrictive on the conditions of use (temperature range, pressure, environment) and therefore do not meet the needs of manufacturers in the refractory concrete sector. Therefore, the objective of the European project named CUBISM, is to fill these gaps by proposing SAW-based pressure sensors capable of operating at much higher temperatures (about 500°C), in wider measurement ranges and in an environment compatible with that of refractory concretes. Developing these types of sensors SAW (Surface Acoustic Wave) consists on choosing the right piezoelectric materials, the optimal IDT (Inter Digital Transducer) configuration and the proper geometry that can withstand these hard conditions. Several prototypes, based on resonators and delay lines have been tested at various temperatures and many pressure levels and the first results show a quite good pressure sensitivity. The results obtained so far will be the subject of this presentation.
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