Piezoelectric sensor, system and method for monitoring the integrity of structures
AssigneeAlma Mater Studiorum - Università di Bologna
InventorsLuca De Marchi, Nicola Testoni, Paolo Francia, Guido Masetti, Alessandro Marzani
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Abstract
The present invention relates to a piezoelectric sensor (1,100) comprising a piezoelectric material (10) interposed between a first (11) and a second (12) electric contact element. The first electric contact element (11) comprises at least two sensing areas (110, 111) spatially separated along a sensing direction. It also describes a sensor node that includes the piezoelectric sensor, a system and a method for monitoring the integrity of a structure using said piezoelectric sensor.
Claims23
Piezoelectric sensor comprising a piezoelectric material interposed between a first and a second electric contact element, where the first electric contact element comprises at least two sensing areas spatially separated along a sensing direction wherein the first of the said at least two sensing areas has the shape of a segment of an Archimedean spiral or of a logarithmic spiral, such that their distance of said separation varies according to the sensing direction considered.
Method for distinguishing the direction of origin of a wavefront affecting a piezoelectric sensor for monitoring the integrity of a structure upon which the sensor is applied, within which a wave guided is detected by the piezoelectric sensor along a sensing direction comprising:
- detecting the time interval between the time instant when the wavefront impacts point (P111) of a first sensing area (111) of a first electric contact element (11) of the piezoelectric sensor spatially separated from a second sensing area (110) of the first electric contact element (11) of the piezoelectric sensor, said first sensing area (111) having the shape of a segment of an Archimedean spiral or of a logarithmic spiral, and the time instant when the wavefront impacts a point (P110) in the second sensing area (110) of the first electric contact element (11) of the piezoelectric sensor along the sensing direction of the wavefront, said second sensing area (110) having a circular shape,
- determine the sensing direction of the wavefront affecting the piezoelectric sensor on the basis of the said time interval and the distance between the two impact points (P111, P110) being known the wave velocity and the geometrical shape of the spiral of the first sensing area (111).
Dependencies are inferred from the claim text.