Bordering the footprint of AE sensor using a bank of sharply-defined frequency domain capacitive micromachined ultrasonic transducers

International audienceThe Acoustic Emission (AE) technique is widely used in Structural Health Monitoring (SHM) in order to detect, in real-time, small-scale damages and to evaluate their kinetics. The piezoelectric transduction is generally favored for detecting the subnanometric displacements of the surface of a material induced by the propagation of the elastic waves generated by the sudden release of energy during damage. Yet highly sensitive, this type of sensor has a great impact on the signals collected introducing interpretation biases when assigning damage families to AE signals. In this paper, new Capacitive Micromachined Ultrasonic Transducers (CMUT) have been designed and tested with the objective to decrease the footprint of AE sensors compared to conventional piezoelectric sensor. CMUT allow getting AE sensors with wide-band and flat response making them of great interest for the collection of AE signals in SHM solutions