Acoustic emission sensor using liquid-on-beam structure

This paper reports on a new approach for Acoustic Emission (AE) sensor, using the multi-layer structure of dimethylpolysiloxane (PDMS)-cover / polyparaxylylene (or Parylene)/ liquid/ beam/ air to conduct vibration propagating medium to the piezo-resistive sensing beam. As the liquid droplet is placed in the middle of the solid sensor cover and the beam, it flattens the Eigen-resonant effect of the beam on vibration sensing process. Therefore, the proposed sensor demonstrated an extra-wide range of measurable frequency of interest up to 10MHz. The pencil lead breaking test demonstrates the ability of this sensor in measuring AE signals on a wide frequency band.