True Unidirectional Piezoelectric Transducer

Context

Piezoelectric sensors are of great importance for non-destructive material testing, strain measurement and quality control. Errors or defaults can be detected quickly and their exact position and size determined. However, when sensing or actuation in a unidirectional direction is required, the presence of a non-negligible transversal effect decreases either the sensing sensitivity of the piezoelectric sensor or the accuracy and/or efficiency of the piezoelectric actuator. The Luxembourg Institute of Science and Technology (LIST) offers a unique unidirectional piezoelectric transducer able to largely improve these measurements.

Overview

The unidirectional piezoelectric transducer developed by LIST measures strain and/or vibration in one direction without suffering from the Poisson effect of the transversal direction. This patented technology provides an original arrangement of comb-like electrodes comprising a pair of planar electrodes and at least one pair of interdigitated electrodes in two neighbouring (distinct) proportions of the piezoelectric material. This particular structure decreases or may even cancel the undesirable transversal piezoelectric effect. This makes it possible to obtain measuring systems with greater sensitivity to electromechanical coupling.

Benefits

• Measurements avoid Poisson effect of transversal direction
• Response depends on only one strain component
• More precisely locate the source of strain
• Increased accuracy of unidirectional measurement

Potential Applications

Piezoelectric transducers cover a large range of applications, the most efficient ones for this unidirectional transducer being:

• Structural testing/verification for structural monitoring
• Material or structural testing for the mechanical domain
• Strain measurement
• Vibration measurement (low frequency: 0-10kHz)
• Sensor/actuator for acoustic propagation (high frequency - >100kHz)
• Active noise and vibration suppression

Possible fields of application include automotive, aerospace, or applied research.